Monthly Archives: January 2017

The neural mechanisms and function of consciousness

How does the collective activity of individual neurons result in a subjective conscious experience of the world? It is one of the core questions in contemporary psychology, cognitive neuroscience and philosophy. Cognitive neuroscientist Simon van Gaal received an ERC grant of 1,5 million euro to bring the answer a little bit closer.

How does something you experience, like a thought or a dream, arise from the electrochemical processes taking place in the brain? To unravel the neural foundations of consciousness, Van Gaal and his team will spend the next five years on a series of studies.

Pharmacological intervention
An important part of the ERC funded project focuses on the molecular processes underlying consciousness. Studies in other animals have shown that the NMDA-receptor might be crucial for recurrent processing, the dynamic information exchange between brain regions. Because recurrent processes are thought to give rise to consciousness, Van Gaal expects NMDA-mediated processes to be essential in becoming aware of a stimulus. To test this, he will do reversible pharmacological interventions in humans in which he temporarily blocks NMDA receptors and measures how this influences the likelihood a subject will consciously perceive a stimulus that is briefly shown.

In order to string the behavioral measures and the molecular intervention together, Van Gaal and his team will use different visualization techniques to keep track of neural activity during the experiments. Specifically, the team is interested in registering to what extent recurrent signaling between different areas in the brain is affected by NMDA blockade.

A potential function of conscious experience
Another part of the project focuses on establishing what purpose consciousness may serve in human functioning. Van Gaal: ‘Consciousness has developed in evolution, possibly because it helps us in some way. But what it is that we gain by having conscious experiences is no yet known.’

It is known that many cognitive and perceptual functions, like processing visual or auditory input or the initiation of motor actions, can operate unconsciously, so these are not the function of consciousness. Van Gaal proposes that consciousness might benefit us by extending the period that information is available in the brain. In order to find out whether this might be true, the research team will measure whether subjects can use unconscious information to base decisions on later in time or whether this retention of information only happens when a stimulus is consciously processed.

Vegetative state
Although Van Gaal is primarily driven by curiosity to understand the fundamental workings of the human brain, in a longer run, he can see these insights resulting in more practical solutions, especially when it concerns insight into the molecular processes involved. Van Gaal: ‘Knowledge of the neurotransmitter-systems implicated in consciousness might eventually help us find ways to treat people who have problems relating to consciousness, patients who are in a vegetative state for example.’

Text: Marieke Buijs

Typically, human behavior is explained as the result of a battle between deliberate efforts to achieve a certain goal and external factors that subconsciously drive our behavior away from that goal. Professor in cognitive psychology Bernhard Hommel proposes an alternative theory about the relation between goal setting and behavior and received an ERC grant of 2,5 million euro to experimentally explore this theory.

Maybe people are not merely actors who, while trying to achieve a certain goal, are distracted by external factors that secretly drive their behavior instead. What if we view people as smart planners, deliberately switching between maintaining focus on their goals and being guided by circumstances? Would that be a better model to understand human behavior?

That is the overarching question Hommel will try to answer in the next five years. He will do so in an approach that spans different levels of understanding, from the molecular processes in the brain all the way up to the interpersonal interactions that are shaped by society. Hommel: ‘It is a high risk, high gain approach. But that is exactly the goal of ERC-funded research. This grant allows me to work in a team of ten scientists to look at the same question on these conceptually distinct levels.’

Because Hommel is interested in the force organizing basic processes like perception, attention and response selection, he will study the network connecting different areas in the brain. For this he has access to a high resolution 7 Tesla fMRI scanner, in which subjects will perform tasks that require either goal- oriented or stimulus-driven behavior, like the Stroop task. Hommel is especially interested in the frontal and striatal dopaminergic networks, because they embody staying focused and flexibly switching respectively. He will also have a close look at the production of dopamine, in the substantia nigra and ventral tegmental areas, as this represents the source of this organization.

On another level, the group will study whether people have control over the brain state they are in. ‘Some people might inherently be better at staying focused on their goal, while others are more flexible in dealing with external circumstances,’ Hommel remarks. ‘But I also think people have control over how they balance intrinsic and external influence on their behavior.’ The psychologist will test this hypothesis by training subjects in two distinct types of meditation. One requires people to stay focused on one thought, fighting off intruding thoughts, the other type of meditation requires the opposite, allowing all thoughts and feelings to be present. Hommel will measure how the different types of training influence the behavior of his subjects.

Artificial mini-culture
Finally, cultural factors also influence people, think for example of how perseverance is regarded as a virtue in Calvinistic societies, whereas going with the flow is more appreciated in other cultures. Hommel will imitate the influence of a societal environment on the extent to which people’s behavior is determined by their goals. He will do so by having participants acquire an artificially created mini-culture – a coherent set of rules that expresses particular norms and values. Subsequently, he will test whether this leads to the same systematic changes in perception, attention, and decision-making that natural religions have been found to produce.

Underlying the research project is Hommel’s concern with the discourse about “free will” that currently dominates psychology. ‘We often presume external stimuli take us off course, undermine our “free will”. But I don’t see a reason to believe stimulus-driven behavior to not be intentional. It can be really smart to adapt to circumstances, both in an ancestral and the current setting. Think about someone chasing a boar and adjusting this behavior when he notices a lion that is about to chase him, or someone nowadays pursuing a career as a singer, but going along with an alternative career opportunity that presents itself instead, going with the ‘distractions’ might be for the better in both scenario’s.’

Text: Marieke Buijs