decision-making

Consciousness – Who decides, 𝘺𝘰𝘶 or your brain?

Posted on by Iasmina Hornoiu

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.

Emotions and the brain

Posted on by Iasmina Hornoiu

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!

Posted on by Iasmina Hornoiu

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 

Why drugs are actually bad!

Posted on by Iasmina Hornoiu

We are all well aware of how serious and, unfortunately, wide-spread drug addiction is, yet we don’t actually know what makes people so dependent of a drug after they have started using it. Even more intriguing is why former addicts, who have stopped using drugs for weeks or months, revert back to drug use, knowing full well that the substance they were addicted to in the past pretty much ruined their lives.

As I am sure you expect this article to shed light on the problem, I’m not going to keep you guessing. Two weeks ago, a team of researchers at the Icahn School of Medicine in US published a greatly revealing study in The Journal of Neuroscience. They appear to have found the answer to how cocaine affects decision-making in addicts as well as why abstinent users often choose to start taking cocaine again.

Dopamine is one of the commonest neurotransmitter in our brains. It is involved in many cognitive processes, including prediction and recognition of loss. Therefore, dopamine plays a very important role is some mental and also neurodegenerative diseases, such as schizophrenia (where dopamine levels are overly increased) and Parkinson’s disease (caused by decrease in dopamine secretion in the midbrain and degradation of dopamine receptors).

This recent study shows that cocaine acts on dopamine signalling, influencing the so-called Reward prediction error (RPE). It has been recorded, fallowing neuroimaging and pre-clinical studies, that dopamine signalling is increased in response to an unpredicted reward (which is scientifically referred to as positive RPE) and decreased as a result to a negative outcome or the omission of a predicted reward (negative RPE). The team of researchers demonstrated, therefore, that cocaine reduces the response to unpredicted loss (impaired negative RPE), while leaving the positive RPE almost intact.

In order to obtain these results, the team used 75 subjects, who were divided into two groups: 25 non-cocaine users and 50 cocaine addicts. Moreover, the second group was also divided as fallows: 25 cocaine users who had taken cocaine within 72 hours of the study and 25 cocaine users who had abstained from taking cocaine within 72 hours of the study. All subjects had to play a computer game that involved prediction and guessing.

As you may expect, the non-users responded normally to both unexpected  loss and predicted reward, as well as to predicted loss and unpredicted positive outcome. On the contrary, the cocaine users responded far less to unexpected negative outcome. This means that their brains were reacting less strongly to the negative result of a prediction than the normal subjects’ brains.

Moreover, and this is the most fascinating part, the users who hadn’t taken cocaine within 72 hours, showed deficit in positive RPE, whereas the other addict group (who had consumed cocaine in the previous 72 hours), had unaffected positive RPE, but impaired negative RPE. Also dysregulation in serotonin system in drug addicts might lead to this kind of results (serotonin signalling has been registered in response to negative prediction, in normal brains).

So, to cut the story short and in a more simplified version, if you use cocaine, you are more likely to omit the bad things in your life. But if you take cocaine and then you give up, you get the opposite result: you become less able to enjoy positive aspects. This might account for the fact that people who stopped taking drugs tend to start using them again after rehab. Does this mean we have to become drug addicts? It seems like this is the solution. Well…NO! Definitely not! And I’m not saying this because I might get into trouble for promoting drug use, but there is a very important reason for that. We DO need to anticipate and recognize negative outcomes. This is how all creatures in this world survive. This is how more advances creatures (like humans) are capable of making good decisions and learn from mistakes.

Some might argue, though, that it is preferable to be happy all the time, despite how much you fail and that there is no such thing as actual failure, as it’s all about how our own brains perceive the environment. What do you think? Is this true or not? Either way, I strongly suggest you don’t start using drugs!

The study

Image modified by Isuru Priyaranga