Human Cognitive Neuroscience
To investigate motivational processes in humans, we
- develop computerized behavioral tasks that target the process of interest
- use neuroimaging techniques (functional MRI, EEG-MEG, local field potentials) to indentify the brain networks underlying task performance
- assess deficits in task performance when the identified networks are affected by neurological or psychiatric disease and their treatment (medication and surgery)
We are currently interested in several pathological conditions where motivation is dysfunctional
- in neurology: Parkinson disease, Huntington disease, Gilles de la Tourette syndrome, Alzheimer disease, fronto-temporal dementia, focal lesions (stroke, glioma)
- in psychiatry: major depression, obsessive-compulsive disorder, schizophrenia, attentional deficit and hyperactivity disorder
Our investigations are tightly linked with both
- primate neurophysiology, as we intend to develop similar tasks, explore homologous brain regions and assess the same treatments (pharmacological medication and electrical stimulation) in monkeys and humans
- computational modeling, as we use formal algorithms to quantify and interpret both behavioral performance and neuronal activity
Our conceptual framework is borrowed from decision theory, in which the cost/benefit arbitration that regulates the direction and intensity of behavior takes the following general form:
Expected Value = Benefit(outcome) x Proba(outcome|behavior) – Cost(behavior)
Expected value is the difference between costs and benefits, which are subjective anticipations attached to any possible action and any possible vigor. In more intuitive terms, the benefit component is made of the desirability of the outcome (or goal) scaled by the chance of success (or confidence), i.e. the probability that the envisaged behavior reaches the goal. The cost component is essentially the intensity of effort integrated over time, i.e. the amount of resources that would be consumed by the envisaged behavior.
The overall aim is to understand how the brain operates such cost/benefit arbitrages, in normal and pathological situations. Our current projects can be divided into 3 research questions:
1. How do neural representations of cost and benefit interact and determine preferences?
2. How is cost-benefit arbitrate affected by internal states such as mood and fatigue?
3. How is cost-benefit arbitrage affected by clinical conditions and treatments?