The biology of meditation. How meditating can change your brain

Many of us are already familiar with what it means to meditate, in a broad sense, and we have often heard that meditation can improve our lives. Several books and articles have been written on the positive effects exerted by meditation on our bodies and minds. But what is the nature of meditation and how can it help us improve our mental states? More specifically, what happens at the level of neural networks, brain cells and molecules that results in all these beneficial actions upon meditating?

This being human is a guest house. Every morning a new arrival. A joy, a depression, a meanness, some momentary awareness comes as an unexpected visitor. Welcome and entertain them all! […] The dark thought, the shame, the malice. Meet them at the door laughing and invite them in. Be grateful for whatever comes. Because each has been sent as a guide from beyond.

The Guest House by Rumi. Translation by Coleman Barks

FIGURE 1 |Sigiriya rock located near the Dambulla town, in the Central Province, Sri Lanka. Own image.

An introduction to meditation ~ its styles and purposes

Meditation encompasses various emotional and attentional regulatory practices, which aim at improving an individual’s cognitive abilities. Many recent behavioral, electroencephalographic and neuroimaging studies have investigated the neuronal events related to meditation, in order to achieve an increased understanding of cognitive and affective neuroplasticity, attention and self-awareness, as well as for their possible clinical implications.

The video below shows the kind of brain changes meditation leads to, in a monk who is a long-term practitioner.

According to Raffone and Sirivasan (2010), a central feature of meditation is the regulation of attention, and as such, meditation practices can be classified into two main styles—focused attention (FA) and open monitoring (OM)—depending on how attentional processes are directed. While the FA (‘concentrative’) style is based on focusing attention on a given object in a sustained manner, the second style, OM (‘mindfulness-based’) meditation, involves the non-reactive monitoring of the content of ongoing experience. More specifically, mindfulness refers to being constantly aware of the way we perceive and monitor all mental processes, including perceptions, sensations, cognitions and affects.

FA meditation techniques imply, apart from sustaining the attention on an intended object, monitoring attentional focus, detecting distraction, disengaging attention from the source of distraction, and (re)directing attention (back) on the object. This kind of attentional stability and vividness is achieved through concentrated calmness or serene attention, denoted by the word Samatha (which literarily means quiescence) in the Buddhist contemplative tradition. Another technique which can be broadly included in the FA meditation is transcendental meditation, which centers on the repetition of a mantra.

Unlike FA meditation, OM meditation does not involve an explicit attentional focus, and therefore does not seem to be associated with brain areas that control sustained or focused attention. Instead, OM meditation engages brain regions implicated in vigilance, monitoring and detachment of attention from sources of distraction from the ongoing stream of experience. Therefore, OM meditation is based on detecting arising sensations and thoughts within an unrestricted ‘background’ of awareness, without a ‘grasping’ of these events in an explicitly selected focus. In the transition from a FA to an OM meditative state, the object as the primary focus is gradually replaced by an ‘effortless’ sustaining of an open background of awareness, without an explicit attentional selection. In the Buddhist tradition, the practice of Vipassana (insight) OM meditation requires, first of all, attentional stability and vividness (acuity), as developed in FA meditation, in order to achieve a deep and reliable introspection.

The ancient yogic practice of Yoga Nidra, which is less-known, and yet is becoming increasingly popular, can also fall into the category of OM meditation. It is said to reduce stress and improve sleep, and that it has the potential to engender a profound sense of joy and well-being.

Another type of OM meditation worth mentioning here is the loving-kindness meditation or non-referential compassion (also known as Mettā in the Pali language), which involves compassion-based mental training aimed at promoting empathy. Practicing this kind of meditation is believed to increase the capacity for forgiveness, connection to others and self-acceptance, and to boost well-being and reduce stress. For more detailed descriptions as well as a deeper and broader understanding of the neurological implications of these different meditation practices, I strongly encourage you to check out the reviews listed in the Reference section, especially Brandmeyer et al. (2019) and Raffone & Srinivasan (2010).

Of all these different kinds, mindfulness meditation, which originally stems from Buddhist meditation traditions, has received the most attention in neuroscience research over the last twenty years.

Research over the past two decades broadly supports the claim that mindfulness meditation — practiced widely for the reduction of stress and promotion of health — exerts beneficial effects on physical and mental health, and cognitive performance. 

Tang et al. (2015)

Sustained engagement with mindfulness meditative practices has been shown to have neurophysiological and psychological benefits. In healthy individuals, several months of mindfulness meditation practice correlates with improvements in self-regulation and subjective well-being. Even much shorter mindfulness meditation training, of a few days, has a positive impact on mood and executive functioning, while at the same time reducing fatigue and anxiety.

Brain structural changes following mindfulness meditation

Several recent studies have investigated the structural changes in the brain related to mindfulness meditation, and have reported alterations in cortical thickness, hippocampal volume, and grey-matter volume and/or density. However, before we dive into how meditation can change our brains, it should be mentioned that there are a few issues with the current state of meditation research. First of all, most of these studies have made cross-sectional comparisons between experienced meditators and controls. But only a few recent studies have investigated longitudinal changes in novice practitioners. These logitudinal studies are very important because they follow subjects over a long-term period of practice, and are thus able to determine whether changes induced by meditation training persist in the absence of continued practice. Therefore, more such studies would be required for a complete picture of the effects of meditation on mental health.

In addition, the studies on mindfulness meditation so far have generally included small sample sizes, of between 10 and 34 subjects per group, which leads to limitations in interpreting the results, as well as increases the chances of false-positives. Another prossible issue is that these studies use different research designs, measurements and type of mindfulness meditation. Hence, it comes as no surprise that the reported effects of meditation are diverse and cover multiple regions in the brain, including the cerebral cortex, subcortical grey and white matter, brain stem and cerebellum. That being said, these findings can also reflect the fact that the effects of meditation involve large-scale and interactive brain networks.

According to various fMRI studies, minfulness meditation exerts its effects primarily (though not exclusively) on a network of brain regions – the Default Mode Network (DMN). This network comprises structures in the medial prefrontal cortex (PFC), posterior cingulate cortex (PCC), anterior precuneus and inferior parietal lobule, which have been previously shown to have high activity during rest, mind wandering and conditions of stimulus-independent thought. These regions have been suggested to support different mechanisms by which an individual can ‘project’ themselves into another perspective.

When comparing meditators with naïve subjects, DMN regions, such as the medial PFC and PCC, have shown much less activity in meditators, across different types of meditation. This has been interpreted as indicating diminished self-referential processing. Experienced meditators also seem to exert stronger coupling between the PCC, dorsal anterior cingulate cortex (ACC) and dorsolateral PFC, both at baseline and during meditation, which indicates stronger cognitive control over the function of the DMN.

Brewer et al. (2011) investigated brain activity in experienced meditators versus meditation-naïve controls as they performed several different mindfulness meditations (Concentration, Loving-Kindness, Choiceless Awareness). They found that the main nodes of the DNM (medial PFC and PCC) were relatively deactivated in experienced meditators across all meditation types (Figure 2). Moreover, functional connectivity analysis revealed increased coupling in experienced meditators between the PCC, dorsal ACC, and dorsolateral prefrontal cortices, both at baseline and during meditation, as seen in Figure 3. This increased connectivity with medial PFC regions supports greater access of the default circuitry to information about internal states, because this region is also highly interconnected with limbic regions (such as insula and amygdala).

FIGURE 2 | Experienced meditators demonstrate decreased DMN activation during different meditation conditions: Choiceless Awareness (green bars), Loving-Kindness (red), and Concentration (blue) meditations. The decreased activation in PCC in meditators is common across different meditation types. Brain activation in meditators > controls is shown, collapsed across all meditations, relative to baseline (A and B). Activations in the left mPFC and PCC (C and D). Taken from Brewer et al. (2011)

FIGURE 3 | Experienced meditators show coactivation of mPFC, insula, and temporal lobes during meditation. Differential functional connectivity with mPFC seed region and left posterior insula is shown in meditators > controls: (A) at baseline and (B) during meditation. (C) Connectivity z-scores (±SD) are shown for left posterior insula. Choiceless Awareness (green bars), Loving-Kindness (red), and Concentration (blue) meditation conditions. Taken from Brewer et al. (2011)

Meditators also reported significantly less mind-wandering, which has been previously associated with activity in the DMN. Therefore, these results demonstrated that alterations in the DMN are related to reduction in mind-wandering. They also suggested that meditation practice may transform the resting-state experience into one that resembles a meditative state – a more present-centered default mode.

The findings from this study have several clinical implications, given that a number of pathological conditions have been associated with dysfunction within areas of the DMN, including depression. The self-referrential function of the DMN has pointed to the possibility that excessive rumination (negative inner preoccupation about the personal past, present and future) in depression involves excessive DMN activity as well as an inability to switch out of it, in response to external demands. Mindfulness meditation may prove useful in reducing distractive and ruminative thoughts and behaviors, and this ability may provide a unique mechanism by which mindfulness meditation reduces distress and improves mood.

In addition, meditation has also been shown to promote neuroplasticity, an important neuronal process that entails structural and functional brain adaptations in response to changes in environmental conditions. A key neurotrophin that promotes neuroplasticity is the brain-derived neurotrophic factor (BDNF), which is usually found in abnormally low levels in various psychiatric and neurological disorders. Meditation has been shown to increase the levels of BDNF, thus promoting neuronal development, survival and plasticity, which in turn contribute to restoring the normal functioning of brain networks.

In sum, there is emerging evidence that mindfulness meditation might trigger neuroplastic changes in brain regions involved in the regulation of emotion and cognition. Although, as mentioned earlier, these studies often suffer from low methodological quality and present with speculative post-hoc interpretations, this is quite common in a new field of research. Thus, further research needs to use longitudinal, randomized and actively controlled research designs and larger sample sizes, as well as to concentrate on the biological factors implicated in mental health, in order to advance the understanding of how mindfulness meditation interacts with the brain. If supported by rigorous research, the practice of mindfulness meditation might be a promising therapeutic approach for clinical disorders, such as depression, and might facilitate the cultivation of a healthy mind and improved well-being.

For the readers interested in the effects of meditation on depression, please visit my article The biological implications of meditation practices in the treatment of depression.

References

  • Brandmeyer, T., Delorme, A., Wahbeh, H. (2019). Chapter 1 – The neuroscience of meditation: classification, phenomenology, correlates, and mechanisms, Editor(s): Narayanan Srinivasan, Progress in Brain Research, Elsevier, 244: 1-29. doi: org/10.1016/bs.pbr.2018.10.020
  • Brewer, J.A., Worhunsky, P.D., Gray, J.R., Tang, Y.Y., Weber, J., Kober, H. (2011). Meditation experience is associated with differences in default mode network activity and connectivity. Proc Natl Acad Sci U S A, 108(50):20254-9. doi: 10.1073/pnas.1112029108
  • Kabat-Zinn, J. (2003). Mindfulness-based interventions in context: past, present, and future. Clin Psychol Sci Pract 10:144–156
  • Heuschkel, K., & Kuypers, K.P.C. (2020). Depression, Mindfulness, and Psilocybin: Possible Complementary Effects of Mindfulness Meditation and Psilocybin in the Treatment of Depression. A Review. Front. Psychiatry, 11:224. doi: 10.3389/fpsyt.2020.00224
  • Raffone, A., & Srinivasan, N. (2010). The exploration of meditation in the neuroscience of attention and consciousness. Cognitive Processing, 11:1-7. doi: 10.1007/s10339-009-0354-z.
  • Tang, Y.Y., Hölzel, B.K., Posner, M.I. (2015). The neuroscience of mindfulness meditation. Nat Rev Neurosci, 16(4):213-25. doi: 10.1038/nrn3916
  • Zeidan, F., Johnson, S., Diamond, B., David, Z., & Goolkasian, P. (2010). Mindfulness meditation improves cognition: Evidence of brief mental training. Consciousness and Cognition, 19, 597-605. doi: org/10.1016/j.concog.2010.03.014.

Volunteering in Sri Lanka

In this article, I will tell you guys about my clinical experience in an extotic and remarkable country.

In November 2018, I completed a four-week Mental Health Foundation Placement in Sri Lanka, as a volunteer for the organisation SLV.Global.

When I decided to join this placement, I was extremely interested in the culture of this small country at the bottom of India, which I had often heard being referred to as “the Pearl of the Indian Ocean”. At the same time, as a final-year undergraduate Neuroscience student, I was looking for a more clinical, psychology-based experience, and was fascinated by the idea of volunteering in mental health, in a country that seemed to be in great need of such work.


A bit about Sri Lanka

Sri Lanka has an extraordinary cultural, ethnic and natural diversity, as well as a long and distinguished history.

Sri Lanka map

Map of Sri Lanka

Religion is very important. This country is the home of one of the world’s oldest and purest forms of Buddhist traditions, approximately 70% of the population being Buddhist. 12.6% are Hindus, especially in the North and East of the country, 9.7% Muslims, and 7.4% Christians. In 2008, Sri Lanka was the third most religious country in the world according to a Gallup poll.

Ethnically, there are two main groups of population, with different languages, the Singhalese (most of them of Buddhist religion and speak Sinhala) and Tamils (mainly Hindus and speaking Tamil). Apart from these, there are also the Moor of Arabic descent, Burghers (descendants of European colonists), Malays and ethnic Chinese migrants who came to the island in the 18th and 19th centuries.

Another name of Sri Lanka is Ceylon. Many people around the world are familiar with this name, due to the Ceylon tea (green and black tea), from the vast upland plantations in Sri Lanka. But the Ceylon tea is just one of the many natural riches that make this tiny island a tropical paradise.

For tourists, Sri Lanka has it all – from very well-conserved ancient vestiges to beautiful beaches, amazing landscapes, impressive temples and incredible flora and fauna, many of which are endemic.

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Temple of Tooth

One of the entrances to the Temple of the Sacred Tooth Relic in Kandy. The interior of the temple is truly spectacular and quite intricate in its structures and decors.

Sigyiria rock (1)

Sigiriya (Lion Rock), one of the medieval Sri Lanka’s most remarkable royal palaces and an unforgettable landmark.

Kandian dance

Dancers performing the famous Kandyan dance.

But many of those who visit this small Indian Ocean country only for touristic purposes sadly overlook the struggles of its inhabitants, reflected, among others, by the issues in the educational and health care systems, widespread poverty, socio-political confusion rising from the centuries-long colonial history (until Sri Lanka’s independence in 1948), and the ethnic problems.  


Mental health problems in Sri Lanka

Sri Lanka deals with an increasing prevalence of mental illness and a high suicide rate. Suicide is the second biggest cause of morbidity and unnatural death. In 2016, Sri Lanka ranked number 31st in the world for the suicide rate. This situation is largely determined by poverty and the traumas caused by a 26-year civil war which only came to an end in 2009. In addition to these, in 2004 the country was devastated by a tsunami, which led to about 35,000 deaths and 516,000 displacements, and which has contributed to the high rate of PTSD, anxiety and depression. Schizophrenia affects around 210,000 people, based on a report by the World Health Organisation, in 1993.

By contrast, Sri Lanka has great deficit in mental health resources, funding and clinical staff.  Only 1% of the government funds is directed to the mental health sector. Currently in Sri Lanka, there are only 89 psychiatrists serving a population of 21 million, and the number of other mental health professionals (psychiatric nurses, psychologists, occupational therapists etc.) is also extremely low.

One of the main causes for the lack of personnel is the stigma attached to mental illness which is perceived as shameful.

People with depression and attempted suicide are subject to discrimination, for instance when seeking a job. The relatives of the mentally ill themselves consider them a burden and abandon them. There are cases of patients after being discharged from the hospital and upon returning home, they were rejected by their own families and left homeless, which determined them to return to the hospital, as that became their only home. In fact, a friendly family environment and a society without the above-mentioned prejudices would allow a successful recovery of the patient.

Stigma affects not only the ill, but also the mental health professionals. The latter are being looked down upon, and so, many of them choose to leave the country and work abroad. Other significant consequences of stigmatisation are the lack of proper training of the mental health staff, as well as the very little advancement of the psychiatric treatment, which in Sri Lanka is mainly reduced to medication and electroconvulsive therapy.

There is need for a change in mentality, so that mental illness stops being considered shameful, and instead it is seen as any other disease, like cardiac or liver diseases. At the same time, it would be necessary that the government, too, take the problem of mental health more seriously, and allocate more resources to it.

It is remarkable the fact that some Sri Lankan psychiatrists have already taken steps in changing the mentality, by organising workshops about mental health in schools and for their patients’ families.


Our projects

The projects run by SLV.Global, in partnership with the mental health charity Samutthana Kings College London Centre for Trauma, Displacement and Mental Health, support the very few local mental health professionals in their attempt to fight the stigma around mental illness, promote alternative therapeutic approaches, and help former patients reintegrate in their community after being discharged from the hospital.

Volunteers stayed at local Sri Lankan families at three different locations – Colombo, Kotte and a rural area called Horana and Bandaragama (I lived in Horana and Bandaragama). This was very important to us, because it helped us better understand Sri Lankan customs and mentalities.

We ran seven sessions per week. The first week was, however, dedicated entirely to the volunteers’ orientation. We participated in workshops with mental health professionals about working with service users, effective session planning, and the mental health situation in Sri Lanka. One of the workshops took place in a Buddhist Thai Temple, where a Buddhist monk gave us tips on meditation, which we were then able to include in some of the therapy sessions we ran.

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The projects took place in a number of different facilities (centres for special needs, vocational training centres, schools, temples, psychiatric hospitals etc.), with service users having a variety of different diagnoses. The sessions we organised focused on enhancing the social skills, communication skills, motor and sensory functioning, and cognitive skills (e.g. short-term and long-term memory, sustained attention, learning, imaginative play) of the service users. Activities included performing dancing routines, yoga for relaxation and mindfulness, musical activities, movement therapy sessions, games (e.g. puzzles, board games).

The main goal of the sessions was to improve the quality of life of the service users, by increasing their general well-being, and supporting them to develop skills that they could use to become more financially and socially independent.

During my volunteering in Sri Lanka, one of the things I truly valued was the fact that the people we volunteered for were referred to as service users (not “patients” or “mentally ill”). This was due to the attempt at changing the mentality around mental illness, by helping the service users feel less like patients and more like any other human being, who deserves respect, love and appreciation.

It was also interesting to see that the sessions we ran included meditation (relaxation yoga, laughing yoga) and breathing techniques, rather than being solely based on Western forms of therapy, which indicated attempts at an integrative approach to mental health.

The projects we worked on were often challenging, as the service users suffered from a variety of conditions, from communication and intellectual impairments to schizophrenia and depression, and we did not have access to any individual service user’s diagnosis or history, since we were not members of the clinical staff. Therefore, we had to figure out by ourselves what best worked for each of them.

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Aside from activities aimed at promoting mental health, volunteers also took part in English for Development projects, which took place in schools, temples, community centres and vocational training centres. These sessions focused on improving the spoken English and communication of students, which would prove very useful for studying or having a job in their home country, as well as abroad.

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Creativity was the key

All volunteers had access to the session planning sheets, materials and ideas used in the past by previous volunteers, but were encouraged to be creative and come up with their own ideas.

During this placement, I decided to use classical music, particularly Baroque pieces, in sessions aiming at improving memory and social interaction. For example, in one session my group of volunteers had the service users at that respective facility (who were suffering from communication impairments, intellectual disability and depression) listen to several classical compositions, and then associate these with drawings of faces representing various moods or feelings. Service users were also encouraged to tell us why, to them, a musical piece evoked a certain feeling. The scope of this activity was to expose the service users to classical music (known for its benefits on the mental processes) and help them form associations between auditory and visual stimuli.

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Another innovative idea, which two of my teammates had, was to use Kendama toys as a means of improving fine motor skills, coordination and forward planning, as well as a stress relieving mechanism. We soon discovered that certain service users suffering from depression and autism-spectrum disorders had become more receptive, more talkative and less aggressive after a few sessions combining Kendamas and classical music.


Ayurvedic medicine and modern medicine

Dambulla

The Golden Temple of Dambulla.

Sri Lanka relies heavily on traditional medical practices based on Ayurveda (Ayurvedic medicine), astrology and religion (mainly Buddhism).

The Ayurvedic medicine involves, among others, the use of herbs, meditation, massages and special diets, in order to prevent and cure disease, increase wellbeing, and decrease stress. The Ayurvedic belief is that health problems are due to a disharmony between mind, body and spirit, and that restoring the balance will restore and maintain health. Establishing one’s diagnosis is based on the person’s medical history, emotions, relationships with other people, and a close examination of different parts of the body. The treatment is then established according to what the practitioner decides best suits the individual.

Alongside traditional medical practices, there are of course modern Western forms of psychiatry and care. One of the largest institutions dedicated to mental health is The National Institute of Mental Health (NIMH) located at Angoda, Kandy District, founded in 1927 and having a capacity of 1,500 beds.

The two approaches, Ayurvedic medicine and Western medicine, should not be seen as opposites. It is clear that both of them have limitations, which is why mental illnesses still persist, and some are even rising. We have to admit that Western doctors are reluctant about ayurvedic medicine. Among the critiques they have provided of ayurvedic medicine are the fact that it is not very scientific, it can have severe side effects, and can interfere with conventional treatment. However, modern approaches, too, have offered neither conclusive answers to questions about the causes or triggers of mental disorders, nor definitive solutions to curing them. In my opinion, instead of rejecting ayurvedic medicine or ridiculing it, we should try to know as much about it as possible, and then decide whether it is suitable or not.

I believe that a great challenge is integrating the Occidental and Oriental views. Sri Lanka is one of the countries with a long-lasting experience in ayurvedic practices, which makes it one of the few ideal places where reconciling the two medical approaches could be successful.


Final thoughts

I left Sri Lanka with the hope that one day I can go back to work in mental health there, and that I can convince more people to do the same. While volunteering there, it soon became clear to me that, in a land where where mental illness is still a taboo topic, volunteers contribute to the wellbeing of the service users simply by their presence. If more people with experience and knowledge in Psychology, Psychiatry and Neuroscience, and who have a genuine desire to help others, volunteer in Sri Lanka, the costs involved in psychiatric treatment there would decrease, alternative forms of treatment would start to spread, and more awareness will be raised about the importance of mental health.

To me, this experience was not only an opportunity to make myself useful, but above all, it was a learning and an eye-opening experience.

When volunteering in Sri Lanka, it is very important to understand the culture, the traditions and the customs there, and try to think outside of the box. An integrative approach, where modern Western forms of medicine and Eastern, more traditional, practices are combined, would benefit not only Sri Lankans, but the volunteers themselves and their own communities.  As volunteers, we can bring back to our countries what we learn in Sri Lanka, and help improve our still-in-progress medical system.

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I would like to thank Prof. Aravinda Ravibhanu SumanarathnaSenior Research Development Scientist at Institute of Professional Studies & Skill Development Sri Lanka, CEO & Founder of Eco Astronomy Sri Lanka Research Unit, and Isuru Priyaranga Silva, BSc. Microbiology student and Eco Astronomy Researcher, as well as their lovely families, for making me feel like home when I was so far away from mine, for offering me valuable information about Sri Lanka, for showing me its beauties, and for revealing to me the well-known Sri Lankan hospitality.

I am also thankful to my homestay family, Uditha Dananjani and Sampath Dissanayake, and to all the Sri Lankan volunteers I had the great pleasure to work with, especially to Gayeshi Lakshika who helped me many times practise Sinhala.

I also thank Prof. Hugh Piggins, Head of School of Physiology, Pharmacology and Neuroscience, University of Bristol, for supporting and encouraging me to volunteer in Sri Lanka.

 

References

De Silva, D. (2002). Psychiatric service delivery in an Asian country: the experience of Sri Lanka, International Review of Psychiatry, 14:1, 66-70, DOI: 10.1080/09540260120114096

Hutter, C., Haputantri, M., Anver, G. (2016). Inside Sri Lanka’s National Mental Health Institute: A Photostory. Retrieved from: https://roar.media/english/life/reports/inside-sri-lankas-national-mental-health-institute-photostory/

Minas H., Mendis J., Hall T. (2017). Mental Health System Development in Sri Lanka. In: Minas H., Lewis M. (eds) Mental Health in Asia and the Pacific.International and Cultural Psychology. Springer, Boston, MA.

Uduman, N. (2018). Mental Health and Stigma in Sri Lanka. Retrieved from: https://groundviews.org/2018/02/19/mental-health-and-stigma-in-sri-lanka/

Oxytocin and Social Bonding

While most of us would be able to describe what being affectively close to someone feels like, we might find it harder to explain why and how such a connection forms.

Why do we love and what makes us love certain people? Why is love so different depending on the subject of our affection? Is it possible to measure love? What does the complete absence of love in an individual reveal about their health state? With so many questions having been formulated throughout centuries, no wonder love has become a universal conundrum. Traversing various disciplines, it not only represents the realm of the literary, but it has increasingly become one of the central focuses in philosophy, biology, social sciences and neuroscience.

As far as the neuroscientific approaches to love go, this concept is represented by affiliative bonds. Therefore, from now on we shall refer to love as such. For the sake of the reader’s personal interest, we shall further discuss affiliative interactions as they appear and manifest in humans. Affiliation describes the ability of an individual to form close interpersonal bonds with other individuals of the same species. Three prototypes of affiliation have been identified: parental (between children and their parents), pair (between romantic partners) and filial (between friends).

This article is intended to introduce the reader to the evolutionary significance and neurochemical mechanisms underlying social bonding/affiliation. As such, the above-mentioned types of affiliative behaviours will be only in part separately discussed. Instead, we shall focus on what these categories share in common, particularly, the hormone-neurotransmitter oxytocin and the concept of synchrony.

Synchrony refers to the process by which the members of a social group collaborate with each other, in order to achieve a social goal. This kind of collaboration involves concordance in time between members, at the level of behaviour and physiological processes (e.g. hormonal release, neural firing). Through these synchronous processes underlying social reciprocity, each member is introduced to the social milieu, becomes adapted to his/her environment and learns how to survive.

Intimate reciprocal relationships between two individuals in a social group help shape the individual’s moral, empathic and pro-social orientation, as well as social adaptation and self-regulation. The interaction between mother and infant is critical to the social maturation and well-being of the young. Human mothers, just like other mammals, exhibit specific postpartum behaviours, such as affectionate touch, high-pitched vocalisations, expressing positive affect, which lead to the notoriously strong mother-infant bond.

This type of specific attachment relationship coordinates the physiology of the infant with the behaviours of the mother. Moreover, this mother-infant synchrony enables the temporal alignment of the infant’s inner state with the responses of the social environment (via the mother). The absence of a proper interaction between mother and child, especially within the critical period (between 3 and 9 months after birth), has been shown to contribute to the development of autism spectrum disorders (for more information on autism, check out this previous article – Decoding autism).

Romantic attachment is another type of social bonding in humans, with significant implications to the normal psychological functioning of the individual. According to recent studies, both parental and romantic relationships share similar behavioural characteristics (gaze, touch, affects, vocalisations and coordination of these behaviours between the members of the pair) and rely on similar neuroendocrine mechanisms. These mechanisms mainly involve a nine amino-acid neuropeptide known as oxytocin.

Oxytocin acts as both a hormone and a neurotransmitter. It is associated with a variety of functions including the initiation of uterine contractions during parturition, homeostatic, appetitive and reward processes, and last but certainly not least, the formation of affiliative bonds. For the latter, oxytocin plays a very important role in social recognition, maternal behaviour and development of partner preferences.

Oxytocin is produced in the hypothalamus, by the magnocellular neurones clustered in two types of nuclei: the supraoptic and paraventricular. These neurones send projections to the posterior pituitary gland, thus engaging the oxytocin system with the hypothalamic-pituitary-adrenal axis, mediating the stress response, as well as parturition, lactation and milk ejection. Other projections from the paraventricular nucleus go to various forebrain limbic structures (e.g. amygdala, hippocampus), brainstem (e.g. ventral tegmental area) and spinal cord. There are also other areas, apart from the brain and spinal cord, which receive oxytocin signalling, such as the heart, gastrointestinal tract, uterus, placenta, testes etc. With such extensive projections, it comes as no surprise that oxytocin is involved in a wide variety of processes.

In romantic and parental attachment, oxytocin induces the motivation to initiate sexual behaviour, the formation of sexual preferences and the increased stimulant value of the infant for its mother, via its connectivity with the mesolimbic dopaminergic neurones. The neurotransmitter dopamine plays a major role in the reward-motivated behaviour. Therefore, the oxytocin-dopamine interaction is key to the motivation to bond between members of romantic or child-parent relationships.

If you were wondering why the parental attachment has so far been presented only from the perspective of the mother-child relationship, that is because in males a different hormone mediates parental behaviour. Vasopressin can be seen as the male equivalent of oxytocin, as it modulates affiliation, aggression, juvenile recognition, partner preference and parental behaviour in males. Having said that, there are studies which show that oxytocin also supports paternal behaviour and is linked to the father-typical affiliative behaviour.

Oxytocin is also very important in establishing close connection with our best friends (what is known as filial attachment). According to research in this area, children start showing selective attachment to a ‘best friend’ around the age of 3. This kind of interpersonal interaction represents the first attachment to non-kin members of society, therefore, a crucial step in the normal development of any human being.

Depending on the level of synchronous parenting children experienced during infancy, their interactions with best friends can vary in the degree of reciprocity, emotional involvement and concern for the friend’s needs. These behaviours are modulated by oxytocin. During the first 3 years of life, oxytocin secretion in humans depends on the parent’s postpartum behaviour (which is predicted by the parents’ own levels of oxytocin) and, in turn, determines the degree of empathy between close friends. Therefore, a reasonable assumption, which has been recently proven, is that children benefiting from high parental reciprocity during infancy develop better social adaptation, are more friendly and cooperative, and show greater empathy.

All in all, the social bonds we form with members of our social group, be they our family, romantic partners or friends, are dependent on certain hormones and behaviours occurring at critical stages of development. Close attachment bonds with our parents, during early infancy, are later translated into affiliations to non-kin members of the social groups, who we come across during childhood, evolving into intimate friendships during adolescence, which eventually shape the ability of the adult human to form and maintain romantic connections and provide nurture for the next generation.

What we have just discussed is of importance for different aspects. Focusing on oxytocin and synchrony provides better understanding of neurodevelopmental disorders such as autism. At the same time, this focus offers some answers to questions regarding the reasons and mechanisms underlying the many types of love us humans experience throughout our lives.

References

Feldman, R. (2012). Oxytocin and social affiliation in humans. Hormones and Behavior, 61(3),  380-391. 

Hammock, E. A. ., & Young, L. J. (2006) Oxytocin, vasopressin and pair bonding: implications for autism. Philosophical Transactions of the Royal Society B: Biological Sciences, 361(1476), 2187–2198. 

Fear and the amygdala

What is fear? Why are we sometimes afraid? Can fear be inhibited? What produces fear – the brain or the heart?

It is definitely the brain! More exactly, something in the brain – a tiny, almond-shaped structure, which sits anteriorly to the hippocampus, called the amygdala. This small part of our brain is to blame for  the perception of fearful stimuli and the physiological responses (increased heart rate, electrodermal responses etc.) to fearful stimuli.

As part of the FEAR system, the amygdala connects to the medial hypothalamus and the dorsal periaqueductal grey matter (in the midbrain), which is important in pain modulation in the dorsal horn of the spinal cord, as well as to sensory and association cortices. The lateral nucleus of the amygdala receives inputs from different brain regions, thus allowing the formation of associations, required for aversive conditioning. Following the processing in the lateral nucleus, information about the stimulus is, then, projected to the central nucleus of the amygdala, where an appropriate response to the stimuli is initiated, provided that the stimuli are detected as threatening or potentially dangerous.

The amygdala is involved in emotional learning and memory, modulating implicit learning, explicit memory, attention, social responses, emotion inhibition and vigilance.

You can find the article on memory here, to brush up a bit.

  • Implicit memory is a type of learning, which cannot be voluntarily reported or remembered. It includes the memories for skills and habits, for procedural knowledge, grammar and languages, priming, simple forms of associative learning and classical conditioning. The latter is particularly important for fear. It involved a conditioned stimulus (CS) and an unconditioned, painful/fearful stimulus (US), with US preceding CS and determining a fearful response to CS. This type of fear learning is adaptive and is known as sensitisation or acquisition.

There are two different pathways in the amygdala, important for fear conditioning. The “low road” pathway: sensory information projects to the thalamus, which directly communicates with the amygdala; this pathway is fast, modulating rapid responses of the amygdala to different types of fearful stimuli. The “high road” pathway is an indirect pathway: sensory information projects to the thalamus and from there, it is conveyed to the sensory cortex for a finer analysis; the sensory cortex, then, communicates the processed information to the amygdala. This pathway ensures that the sensory stimulus is the conditioned stimulus. So the responses of amygdala to threatening stimuli are both rapid and sure.

  • Explicit memory refers to the memory of facts and events; in the case of fear is means the processing and retention for a long time, of emotional events and information. For this type of fear learning, the amygdala interacts with the hippocampus. There is a distinction between the formation of memory for aversive experience (fear conditioning), which is based on previous experience, and explicit learning (in the hippocampus), which involves learning and remembering aversive properties of different threatening stimuli. The memory in the hippocampus is enhanced by arousal produced in the amygdala. The activation of the amygdala can make different cortical areas, not just the hippocampus, more receptive to stimuli that are adaptively important, thus ensuring that unattended, but important stimuli gain access to consciousness.
  • Social responses involve the ability to recognise a stimulus as good, bad, neutral or arousing. This ability, however, does not depend on the amygdala. There is one exception here, otherwise we wouldn’t be talking about it in the context of fear mediated by amygdala – fearful facial expressions. According to Darwin, social species, like humans, use facial expressions to detect internal emotional states of other members of the group. This function, mediated by the amygdala, is crucial in the emotional regulation of human social behaviour. Damage to amygdala has been demonstrated to result in impairment of the patient to identify fearful faces correctly and, therefore, react to them, accordingly. It should also be noted there is no need for the subject’s awareness of the fearful stimulus, for the amygdala to respond. In other words, when a fearful facial expression is presented subliminally, the amygdala will still show activation.
  • Inhibition of fear – it is actually very difficult to escape your own fears, as fear proves to be resistant to voluntary control. However, there is a process called extinction, a method of classical conditioning, where a CS previously associated with an aversive US in presented alone for a number of times, until the CS no longer signals the fearful stimulus. If the US is presented again, after the passage of time, it will evoke fear responses, but in different brain areas. So, the learned fear has been retained in memory, but extinction learning eliminates the response to fear. This mechanism of extinction relies on the activity of NMDA glutamate (excitatory) receptors in the amygdala. When these receptors are blocked, extinction is inhibited (so you will react to fearful stimuli) and when they are active, extinction is augmented (you no longer respond to aversive stimuli).
  • Vigilance – the amygdala is not necessary for the conscious experience of emotional states, but it plays a major role in increasing the vigilance of cortical response systems to emotional stimuli.

Memories about fearful events, just like other types of long-term memory, become permanent through a process of gene expression and novel protein synthesis, which is known as consolidation. Upon retrieval, the memories become susceptible to change and alteration, before they are reconsolidated, which involves additional protein synthesis.

The fact that humans (and probably other animals as well, I am sure, although not widely proven) have the ability to distinguish between emotional information and unemotional information is regarded as an evolutionary advantage. Emotional stimuli signal dangers and the ability to detect and appropriately react to them increases the chance of survival. However, exacerbated fear is detrimental to the individual who experiences it and is a sign of pathology. For instance, in atypical monopolar depression, which includes anxiety as one of the main symptoms, the amygdala is overactive and it determined lowering the threshold for emotional activation and abnormal reactions to stressful stimuli. A similar pattern can be seen as a result of partial chronic sleep deprivation or complete acute sleep deprivation.

References

 Beatty, 2001. The Human Brain – Essentials of Behavioural Neuroscience, Sage Publications Ltd., pg. 293-296

Bernard et al., 2007. Cognition, Brain and Consciousness – Introduction to Cognitive Neuroscience. 1st edition. Elsevier Ltd., pg. 373-383

Gazzaniga et al., 2002. Cognitive Neuroscience – The Biology of Mind. 2nd edition. W.W Norton & Company, Inc., pg. 553-572

Image by  Saya Lohovska. You can find her arts page here.

Consciousness – Who decides, 𝘺𝘰𝘶 or your brain?

If you were to answer the question “What differentiates humans from other organisms on Earth?”, you would probably list a number of things, including the ability of humans to make “free choices” dictated by their consciousness, rather than by something organic. Am I right?

What if someone told you that this is not actually the case? I mean, what if instead of making decisions out of your own will, your brain is “deciding” for you and only after the decision has been made the brain offers you the illusion of conscious act, making you believe that you were the one who made the choice in the first place. But how is it possible that such a dichotomy exists within ourselves, between us and our own brains? Aren’t we our brains? Apparently not!

Now that I (hopefully) managed to capture your attention, I’d like to bore you a bit with some brain structure names and functions, which are necessary in order to begin to understand what’s going to come next.

The frontal lobe contains a few areas, which are involved in planning our movements, decision-making, emotions (usually associated with the decisions we are about to make), repeating previously memorised motor sequences etc. These are the areas involved in voluntary motor control, more specifically, these are the areas that make the difference between reflexes/automatisms and movements or actions we want to pursue. Moreover, all these motor areas are interconnected and also linked to areas that are part of the sensory pathways, such as the parietal , visual, somatosensory and temporal regions (which store different components of visual, auditory and somatic stimuli and are associated with many diseases, such as the inability to feel your own limbs, or recognising faces/objects etc.).

  • The primary motor cortex (PMC) is mainly involved with the execution of movements. Populations of neurones in there encode for the direction and amplitude of the movements we make, prior and during the execution.
  • The 6 pre-motor cortices, the ventral, medial (supplementary) and dorsal areas are mostly involved with planning our movements. They receive inputs from the cerebellum and basal ganglia, which play very important roles in motor learning (like acquiring new skills) and motor planning. Interestingly, different neurones in the pre-motor areas fire action potentials during execution and are inactive during planning of movements and others vice-versa, while some populations of neurones are active for both planning and execution.
  • The prefrontal cortex controls reasoning and decision-making and it is crucial for emotion as well: recall Phineas Gage’s story and how the damage to his prefrontal cortex resulted in a complete change in his personality (article here) as well as how the prefrontal cortex regulates the activity in the hypothalamus and is disrupted in major depressive disorder (article here)
  • The limbic system (amygdala, anterior cingulate cortex, hippocampus) , which are located at the subcortical level and behind the frontal lobe, are involved with emotion, fear and the formation of memories, which are so important in our decision making. And these are just the main players, but there are many other areas, including sensory, which contribute to the planning of our actions and the choices we constantly make.

In a rather groundbreaking paper, Libet and colleagues showed that the neural processes leading to the initiation of voluntary movements begin several hundred milliseconds before the reported time of conscious intention to make the movements, as in before the subject is aware of the intention to move. They demonstrated using the readiness-potential (negative electrical potential recorded at the scalp) that brain activity involved in decision-making starts before our brains is conscious of the actions. This is also known as ‘preparatory set”.

Dick Swaab proposed that the unconscious brain areas are active before the conscious ones, in order to enable us to make decisions rapidly and effectively, as the conscious systems require time to process and analyse the pros and cons of every decision. And although it is good to consider the consequences of your actions, there are many other decisions about apparently insignificant things, which we make and need to be fast (like for example, running away from a car you see coming). In a dangerous situation, for example, the parts of the brain involved in consciousness might consider the state of your legs, how capable they are of moving fast at that point, your heart rate, blood pressure, levels of energy needed for that action…Well, by the time your brain finishes analysing all these, you will be most certainly dead.

Another interesting idea Swaab suggested was regarding the reason why we have consciousness of our actions and the things that happen to us in the first place. We need to be conscious of our own experiences so that we learn to avoid negative things in the future and also act upon things that require intervention, such as a wound that needs to be treated. Although the brain seems to be able to plan an action independently of our awareness of it, other brain areas are involved in the execution (as previously mentioned) and the communication between these different parts which fulfil different roles results in consciousness. Exactly why and how evolutionary biology has managed to make us more than just some purely mechanical creatures remains a mystery and still poses many challenges to this field of research, inviting philosophy to have its take on this matter, which many times has proved to be useful.

Swaab also wonders to what extent are criminals, pedophiles, murderers to blame for their bad actions, when it is in fact not them, but their unconsciousness/instincts that dictate them what to do. When considering that people with brain damage resulting in impaired or lack of consciousness (schizophrenia, dementia, multiple sclerosis etc.) sometimes hurt other and are not convicted, you might think that it is right to assume that all criminal acts should be tolerated. However, the difference here is that people not suffering from such disorders are aware of their actions and are capable of stopping them. Although pedophilia is considered a psychiatric disorder, unlike the neurodevelopmental and neurodegenerative ones, it can be controlled by the individual, so that the individual is able to refrain from acting according to his/her instincts. Libet and his team of researchers mention in their study that individuals, although only aware of the intention to make a particular action after the intention has been formed in their brains, are able to “abort the performance” of the action, meaning that they have a conscious “veto”.

They also emphasise the difference between spontaneous, rapidly performed actions, and actions in which a preplanning of the experience occurred (taking into account alternative choices, for instance). This second type of voluntary movements, involving conscious deliberation prior to the act, might actually rely on conscious initiation and control, rather than non-conscious commands. However, this hypothesis has not yet been proved experimentally, in a way the “unconsciousness before consciousness” one has.

So, as it turns out, most of the times we are aware of our brain’s decisions only after they have already been made, and free will seems to be an illusion.

References

Libet et al. paper

Antonio Damasio,1995. Decartes’ Error. Vintage Books, pp. 71-73

Dick Swaab, 2014. We are our brains – From the womb to Alzheimer’s. Penguin Books, pp.326-338

Image by Saya Lohovska. You can find her arts page here.

Why “sleep”?

In a previous article, we talked a bit about narcolepsy as one of the very intriguing sleep disorders. It was perhaps easy to understand why people suffering from narcolepsy could have a pretty hard time performing several normal tasks; however, most of us would probably relate less to narcolepsy. But something which almost everyone can agree to have experienced regularly, in one way or another, is sleep. In comparison with disorders associated with it or derived from its impairments, sleep itself might not seem so interesting. We all do it and we can’t deny how much we enjoy it and long for it after it stops. Yet, there is much more to sleep than we think.

Sleep is very important for the normal functioning of any being. For animals as well as for humans, sleep helps in energy conservation, body restoration, predator avoidance and learning aid. Different animals have different sleep-wake cycles, from nocturnal animals (like rodents), which sleep during the day and are active at night, and animals which sleep with only half of the brain (like dolphins), all the way to diurnal animals, like humans. Although humans are advised to sleep approximately 8 hours per night, some people sleep very little (around 2-3 hours/night) and still function perfectly fine. An example of such a situation is presented in the textbook of Rosenzweig et al. (pg. 389).

But what triggers sleep and how is it regulated?

Most of us are certainly able to recall a dream the next morning and the memory of that dream is usually accompanied by feelings and emotions we sometimes do not even experience in real life. We are often under the impression that our dream has lasted the whole night. In fact, there are two stages of sleep, one of which is associated with the formation of dreams. These stages, known as non-REM sleep and REM sleep, succeed each other in cycles lasting approximately 90 minutes. Just to define the terms, REM means rapid eye movement and represents the part of sleep with the most increased brain activity. Interestingly, during REM the brain seems to consume more oxygen than during arousal!

Normally, when we fall asleep we slip into the non-REM stage or the slow-wave sleep (SWL). This, in turn, is divided into four other stages: from light sleep to very deep sleep. During this phase, the brain is said to be truly resting and the body appears to repair its tissues. No dreams can be seen! The movement of the body is reduced, but not because the muscles are incapable of moving; it’s the brain which does not send signals to the body to move! One interesting feature of non-REM sleep is sleep-walking. This peculiar behaviour some people show while asleep usually takes place during the fourth (last) part of the non-REM sleep, when the person is the deepest sleep. This is the reason why it is very difficult to wake a sleepwalker up.

In turn, REM sleep (which starts after a 30-minute non-REM period) is the “active” part of our sleep. This time, the brain sends commands to the body, but the body seems to be in an almost complete state of atonia (immobility). The heart rate and breathing become irregular and the brain is not resting. In fact, our dreams happen during this time and more importantly, our long-lasting memories are thought to be integrated and consolidated.

FullSizeRender-2

When it comes to sleep regulation, many neuroendocrine systems and brain functions play a role. The circadian (or sleep-wake cycle), which is controlled primarily by the suprachiasmatic nuclei, in the hypothalamus, need special attention. For the purpose of this article, I won’t focus on the circadian clock now, but I will come back to this in a future article. The autonomic nervous system and parts of the brain such as the brainstem, the limbic system, especially the amygdala, and the forebrain modulate different aspects and stages of sleep. Amygdala, which I mentioned in a previous article about emotions and decision-making, is a brain region involved in the emotions such as fear. It also appears to be very active during REM-sleep and may account for the awful nightmares we often experience.

Many cognitive functions, such as intelligence, performance and emotions are associated with disrupted non-REM as well as REM sleep. To be more specific, REM-sleep loss appears to be associated with increased anxiety and stress and loss of emotional neutrality – this means that a person deprived of REM-sleep is more likely to react negatively to neutral emotional stimuli than in normal conditions. The explanations vary, but most of the studies agree that impaired REM sleep triggers increased release of noradrenaline, hyperactivity of amygdala and decreased function of prefrontal cortex (which tells “stop!” to the amygdala when it goes crazy). At the same time, people deprived of non-REM sleep could experience depression, due to deficiency in another neurotransmitter, this time an inhibitory one, called GABA (gamma-aminobutyric acid). Other problems linked to sleep deprivation are attention deficits, working memory impairments and usually affected divergent thinking (creative, innovative thinking).

Aging people seem to sleep less and this deprivation is also associated with conditions like Alzheimer’s. Moreover, sleep deprivation can kill you! Sustained sleep loss can cause low immune system and drop in body’s temperature, which can make bacterial infections fatal. Another consequence of sleep loss is increased metabolic rate, which leads to weight loss and eventually death. Don’t think this could be a good idea for a diet! More like for “die”!!! Having said that, most people should try their best to get enough hours of sleep.

I hope this article convinced you of the importance of sleep and as usual, any questions or comments are welcome 🙂

Further information:

Article 1 – about REM-sleep and emotional discrimination 

Article 2 – about non-REM sleep and GABA 

Article 3 – about how sleep loss affects behaviour and emotions

Article 4 – a review on many articles about the link between sleep deprivation and emotional reactivity and perception

Bear et al., 2006. Neuroscience – Exploring the Brain. s.l.:Lippincott Williams & Wilknins 

Rosenzweig et al., 2010. Biological Psychology – An Introduction to Behavioural, Cognitive and Clinical Neuroscience. 6th edition. Sinauer Associates Inc.,U.S., pg. 380-401

Both images by Gabriel Velichkova

Emotions and the brain

Once upon a time, I promised I was going to write an article about how emotions affect our decision-making and why it is actually important not to ignore the feelings we have in certain situations…For several, unexplainable reasons I kept postponing this idea, and for that I am very sorry. Having said that, there is no better way of making up for this than to finally keep my promise. So, here we go!

I think I should start off with a small mention: emotions and feelings are distinct things, according to neuroscientist Joseph LeDoux. As he well puts it: “…feelings are what happen when we become consciously aware that our brain is reacting to some significant stimulus,” while it is possible that some brain structures, such as the amygdala “respond to emotional stimuli without the organism being aware of the stimulus.”

In order to achieve a better understanding of what the process of forming emotions involves, scientists talk about emotional experience and emotional expression. The latter refers to body manifestations and behaviours in response to certain stimuli, for example changes in facial expression, heart rate, sweating, skin conductance etc. It has been a subject of debate for several decades whether emotional experience or emotional response is the one responsible for formation of the other, or that they act independently. It is now believed that different emotions depend on specific parts of the brain and are determined by different neural circuits.

But why should we care about emotions in the first place? Some of you might find it strange, but emotions are intensely interconnected with reasoning and decision-making. And no, I don’t mean that they impair the process of making the right decision, it’s actually quite the opposite: most of the times we need emotions in order to be able to do what is best for us in a certain situation.

An interesting case: Phineas Gage 

A man who has gone down in history for surviving a terrible accident at the work place, but maybe mostly because of his importance in understanding the role of emotions in decision-making, is a late 19th century foreman, Phineas Gage. He had been hired as a foreman on a railroad construction site in Vermont and one of his tasks was to sprinkle explosive powder into blasting holes. This sounds like a dangerous thing to do, but Gage was regarded as one of the best people in this field: he was said to be very efficient, energetic, balance-minded, tenacious, a smart and successful business man etc.

One moment of carelessness dramatically changed his life forever, and at the same time had a huge impact on the way scientists began to think of emotions. The powder exploded and a tamping iron entered Gage’s head under his left eye, passing through his left frontal lobe, and exited the skull, leaving a hole which measured more than 9 cm in diameter.

Gage survived, but he “was no longer Gage”, as his friends and acquaintances used to say. Apart from losing vision in his left eye, the man had no motor or sensory deficits, he could hear, touch, sense, walk and talk. It was his personality that was completely changed. He became capricious, irreverent, impatient, and behaved as if he did could not predict, nor care about any professional or personal failure. He was soon fired and found different jobs over time, most of which were related to the accident and the iron rod, which had turned him into some sort of freak.

Some explanations and brain functions

The limbic system is probably the first to come to mind if you refer to brain areas involved in emotions. It consists of structures around the thalamus or in the temporal lobe, such as the amygdala, the hypothalamus, the limbic cortex, the cingulate gyrus, the fornix, the corpus callosum etc. Each one of these structures is involved in specific types of emotion and in triggering certain behaviours or responses through the autonomic nervous system. For example, the amygdala is linked to fear and aggression. Different regions (nuclei) in the amygdala are associated certain functions, so that both emotional expression and experience require the amygdala in order to be formed. Projections from amygdala are sent to the hypothalamus, which determines the autonomic response, the brain stem for behavioural reaction and the cerebral cortex, which is involved in emotional experience. The amygdala is also thought to play a role in enhanced emotional memory.

Regulation of specific emotional behaviours depending on the limbic system is facilitated by one of the major neurotransmitters, serotonine. Neurones containing serotonin originate in the brain stem (in the Raphe nuclei) and send projections to the hypothalamus. Serotonine is associated with a decrease in aggressive behaviour, but at the same time is involved in dominance, as proven by studies in rhesus monkeys.

The Papez Circuit (named after the neurologist James Papez who came up with the idea of an “emotional system”) is composed of interconnected anatomical structures (many of which are part of the limbic system) that link emotional expression and emotional experience together. Papez proposed that the cingulate cortex determines emotional experience, while the major structure involved in emotional expression is the hypothalamus. 

Below I have inserted a diagram showing the Papez Circuit, based on information from Bear et al. Note that the hippocampus is now thought to have less importance in the process of emotion formation.

The Papez Circuit

The discussion above does not fully explain what happened in the case of Phineas Gage. There is much more to emotion than that! Given the fact that the iron rod severely affected Gage’s frontal lobe, we should definitely focus our attention on this structure, too. The frontal lobe and the prefrontal cortices are involved in planning, reasoning, social behaviour, motivation, defining our personalities etc. Damage to these regions, especially to the ventromedial prefrontal cortices, results in decision-making impairment. While the intelligence and the other body functions remain intact, the patient who has suffered the damage is no longer able to exhibit normal social behaviour. The patient becomes emotionless and this lack of emotions and self motivation makes them incapable of making the right decisions.

If instead of the ventromedial prefrontal cortices, another region of the prefrontal cortices is affected, there is a very strong possibility that the patient’s intellectual abilities are compromised, along with their ability to form emotions. This region is called the dorsolateral prefrontal cortices. The person with a damage in this brain area would encounter severe difficulties when it comes to operations on numbers, words, space etc.

Another brain structure involved in the process of emotion forming is located in the right hemisphere. If the somatosensory cortices of this area are injured, the result would be similar to what can be seen in the case of a damaged ventral prefrontal cortex, but there is something more…the processes of basic body singling are also disrupted. This can be observed in patients suffering from anosognosia, a disease in which the patient is unaware and denies their disability.

I have tried to comprise a lot of information and simplify things as much as possible. If you managed to get here with both eyes open, I couldn’t be happier. Hopefully, you can see now why we should also “think with our hearts” when we need to decide about a certain situation…because the “heart” is somewhere in the brain and it knows better than us what we need to do.

For further information:

Antonio Damasio,1995. Decartes’ Error. Vintage Books

Bear et al., 2006. Neuroscience – Exploring the Brain. s.l.:Lippincott Williams & Wilknins pp. 564-581

Article about Phineas Gage

Image by Isuru Priyaranga 

Yourself…and decision-making!

I recently came across a very interesting post on Facebook, written in Romanian. This post especially caught my attention first of all because it had been made by a group very dear to me, Yourself; secondly, the topic was exactly the one I was thinking about for my next article. It’s about the role of emotions in decision-making. To be honest, this is something I’ve been studying for a while and I’ve been struggling to synthesise the main ideas for an article. But this post had it all: it is clear, concise, easy to read and definitely not boring.

I now have a very good starting point for my article. So in the meantime, I thought, why not translate it? 🙂

“When we were small it was easy to write letters to Santa, because we knew exactly what we wanted and we made choices with no difficulty. But as we grew older, things got a bit more complicated; the further we navigate the path to maturity and complexity of life, the more it becomes a challenge to make up our minds.

Why is it sometimes so hard to make choices?; Why do we get anxious and agitated whenever we have to face the impossibility of making a decision? Perhaps it comes down to the fact that the process of decision-making involves many options, and taking the variables into consideration involves both reason and emotions.

The logical process of decision-making is based on determining the value of each option. We often try to rule out as many emotional aspects as possible, to detach from them, and to evaluate each alternative in a logical, almost mathematical, way.

On the other hand, decisions we make in particular emotional states, such as when we are angry or extremely happy, are said to be “in the heat of the moment”. So, which one of these two alternatives represents the best way of making a decision?

Antonio Damasio, a Neuroscience specialist, performed studies on people with deficits in the prefrontal cortex (which is responsible for decision-making, among other cognitive functions) and the cortical structures involved in generating emotions. These people would hardly make even the simplest decisions, such as choosing between fish or chicken as a meal, going shopping, taking a walk etc. He also noted that these individuals were able to reasonably evaluate the consequences of their choices and objectively analyse the alternatives, but could not or it was extremely difficult to make any decision, no matter how simple they were.

Going back to the idea of multiple variables in decision-making, emotions are part of these variables and it is important to acknowledge their role in this process. Life is full of choices and decisions, and we have to face them all. Moreover, if our decisions are based on strong moral values, we will find the necessary means to deal with any potential challenge, regardless the final choice (which we could be quite uncertain about).”

I hope you enjoyed it! 🙂

Drawing by James Dowinton

Yourself Facebook page 

Yourself website 

Mechanisms of schizophrenia

It took me a while to figure out whether to divide this article into two parts or to sum up everything in one long, possibly tedious reading. Honestly, I still don’t know, so I’ll just start writing and we shall see what it turns out to be.

I’m sure you’ve all heard of schizophrenia – the disease of thought disorder, or know people who suffer from it. But only a few actually understand what it is about.

No wonder scientists have been struggling to develop efficient treatments for schizophrenia; not only is it largely uncommon (1% of the world’s population is affected), but also its causes are usually unknown. Scientists generally refer to schizophrenia as a psychiatric disease involving a progressive decline in functioning, which begins in early adolescence and persist throughout the patient’s life. Due to its heterogenous symptoms and multiple possible causes, there are many hypotheses that intend to explain what triggers schizophrenia and how it develops.

In spite of the fact that is it a genetic disorder, the environment and external factors (such as viral infections during the intrauterine and infant period) may be crucial to the development of schizophrenia. The symptoms have been divided into two categories. The positive symptoms include thought disorder, hallucinations, delusions, disorganised speech etc., whereas the negative symptoms are characterised by poverty of speech, reduced expression or emotion, memory impairment, anergia, abulia etc. In addition, the brains of schizophrenics show structural macroscopic abnormalities (for instance, the enlarged ventricles and the shrinkage of the surrounding brain tissue), as well as microscopic changes, such as the dysregulation of dysbindin gene in the formation of abnormal dendritic filopodia. There are three types of schizophrenia, according to its symptoms: paranoid schizophrenia – auditory hallucinations, delusions, strong belief of being chased by powerful people; disorganized schizophrenia – reduced emotions and lack of emotional expressions, incoherent speech (mostly negative symptoms); catatonic schizophrenia – impairment of movement, usually immobility and catatonia, bizarre grimacing (this is similar some of the symptoms of hysteria, which has been described as a sexually related and later on, as a psychiatric disorder up until the beginning of the 20th century).

But enough with the boring general details! Let’s get to the fun part: The monoamine hypothesis of schizophrenia! Here we are going to talk about two very important neurotransmitters in the central nervous system: dopamine and glutamate. The second one is the main excitatory neurotransmitter in the brain. There are four main types of glutamate receptors: AMPA, NMDA, kainate and mGluRs. It has been demonstrated that reduced activity of the NMDA receptors can result in some of the negative symptoms of schizophrenia (lack of social behaviour, catatonia).

Dopamine is the metabolic precursor of another neurotransmitter, noradrenaline (norepinephrine). But there is a lot more to dopamine and its roles in the brain than this. There are four main dopaminergic pathways: the mesolimbic pathway – related to the “reward” system and significance; it has its roots in the ventral tegmental area and projects to the nucleus accumbens (in the ventral striatum) and the limbic system; the mesocortical pathway – involved in cognition and motivation; the tuberoinfundibular pathway – roles in lactation; these dopamine neurones originate in the hypothalamus; the nigrostrial pathway – involved in movement planning and connects the substantia nigra (midbrain) to the striatum.

Schizophrenia and another mental illness, a neurodegenerative one, Parkinson’s disease, are also linked to dopamine. When it comes to schizophrenia, it seems that the mesocorticolimbic pathways have more influence on its onset: the ‘positive’ symptoms appear to be triggered by dopaminergic hyperactivity in the mesocorticolimbic system. At the same time, hypoactivity of dopamine is this region is the cause of ‘negative’ symptoms. Nevertheless, it has been discovered that overexpression of the dopamine receptor D2 (DRD2) gene in the striatum also reduces motivational behaviour in mice, therefore mimicking psychotic ‘negative’ symptoms. Similar findings show that increased density of dopamine D2 receptor in the striatum, along with lower thalamic density of this receptor appear to induce divergent thinking, which is associated with schizophrenia.  

All these changes may account for the abnormalities that we see in “mad” people. It seems that we are so fragile, given that often small chemical and physical disruptions can trigger something as big and terrifying as schizophrenia. Imagine hearing, seeing, feeling, smelling things everyone says are not real (schizophrenics often have multiple hallucinations: auditory, visual, gustatory, tactile, olfactory). But to you they are so real and disturbing! Many schizophrenics even hear their own thoughts as if they are coming from the outside and therefore believe that everyone knows what’s in their heads. Imagine having the constant feeling that someone is after you (paranoia) or being certain that you are dead (the Cotard’s Syndrome) or that your husband has an affair (the Othello Syndrome).

I think this topic can never be fully covered and we would spend days talking about schizophrenia, so this article should better come to an end. As I am sure you have lots of questions and comments, don’t be shy and post anything you think it’s relevant to what has been discussed above. Hope you enjoyed this reading.

For further information: 

Bear et al., 2006. Neuroscience – Exploring the Brain. s.l.:Lippincott Williams & Wilknins, pp. 679-684

de Manzano et al., 2010. Thinking Outside a Less Intact Box; Thalamic Dopamine D2 Receptor Densities Are Negatively Related to Psychometric Creativity in Healthy Insividuals. Public Library of Science

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Image by Damaris Pop

Empathy and…mirror neurons!

As I am quite sure all of you have watched Titanic at some point in your lives or at least know the story, I’m gonna ask you one simple question? How did you feel when Jack Dawson died at the end of the movie? Did you burst out into tears, did you feel an overwhelming sadness? If the answer is Yes! (and should be, unless you are some socio-paths, heartless people – just kidding, I didn’t cry either!), this article is meant to briefly explain what actually happened in our brain at that time. 

Psychologists would call this empathy. And that’s true. For a few moments you were experiencing what Rose was feeling while she was seeing her lover freezing to death and then drowning. But why did you empathize with a movie character? What do humans empathize at all? It all comes down to neurons. In order to try to understand this complex process that lies behind our ability to put ourselves in someone else’s place, we need to figure out the neurological mechanisms that triggers all this. (This could be a good excuse when someone calls you a wet blanket, for example: ‘It’s not me, it’s my mirror-neurons and oxytocine signalling in the anterior cingulate gyrus’, as you’ll see below) 

Some special motor neurons have been discovered in the frontal lobes of monkeys, that apparently signal both when the animal is performing a particular task and when it’s seeing someone else doing the same thing.They were called mirror neurons.  It’s important to bear in mind: “the same thing”, because for another type of action, other mirror neurons would show activity. Thus, these neurons are highly specific. Evidence of mirror neurons have been recorded in humans as well, using neuroimaging, but there isn’t a 100% certainty they actually exist, as it is in macaques and apes. 

Researchers now believe that mirror neurons (if they indeed exist in humans) are also involved in the development of learning (in particular, in language formation); they also appear to account for the evolution of mankind throughout the history (from homo sapiens to homo sapiens sapiens – around 200,000 years ago – and the development of arts, modern tools, religious beliefs – later on, around 40,000 years ago). Moreover, many scientists see dysregulation in mirror neurons’ activity as a possible cause of autism – one of the primary symptoms of this disease being the incapacity of the patient to relate himself to the exterior world, hence the anti-social behaviour. 

There are many other long-known brain structures which trigger emotions and empathy, such as the anterior cingulate gyrus, the amygdala, the hippocampus, the neurotransmitter oxytocin…But mirror neurons are a quite novel discovery and may set neuroscientists on track to explain complex processes that happen in our brains. Cool, right? 🙂 

This article is not only about mirror neurons, but also about empathy. I put a link to a short video filmed in India, in which a macaque monkey is being resuscitated by another one, after having been electrocuted. Some say this is a clear sign of empathy in animals (at least in the superior ones; also elephants, dolphins have shown many signs of empathy before). Other say it is a normal altruistic behaviour, present in most animals (from insects to mammals). Ethologists and population geneticists refer to altruism as one of the instincts of putting others in your species first in order to assure species’ survival and evolution and is mostly encountered in animals that have lived in groups. 

What do you think? Do some animals empathise or what we might see as an empathic behaviour is nothing more than pure adaptive instinct?

Monkey video

Interesting article about mirror neurons

Article – Empathy brain differences