21 février 2018
14h-16h
Louvain-la-Neuve
Salle Jean Ladrière - Collège Mercier - Place cardinal Mercier, 12
Prochaine séance de l'ARC par Gérard Derosière et Caroline Quoilin
This will consist of two short presentations by Gérard Derosière and Caroline Quoilin.
Neural bases of action-based decisions
Gérard Derosière
Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
Human modern life entails the need to make many abstract, deliberative decisions such as selecting a career or buying a house. This fact prompted the development of theories suggesting that decisions are made within a cognitive system prior to being relayed to the motor system for outputting the desired action: a serial architecture of sensing, thinking, and finally acting. However, the human brain is the product of a long evolution during which animals had to face challenges very different from our modern-life decisions. Most decisions in the animal realm must be made in real-time to cope with urgent priorities in dynamically changing environments: here, there is no time for carefully thinking before acting. A recent theoretical framework has proposed that for effective behavior in such environments, the brain uses a parallel architecture in which multiple potential actions can be specified simultaneously, and one is selected on the basis of current sensory information. This is called the affordance competition hypothesis. According to this theory, decisions emerge from a consensus arising in a distributed brain network, especially involving sensorimotor structures.
In this presentation, I will describe the work I have been conducting for the three last years as a postdoctoral researcher at the Cognition and Actions lab (headed by Pr Duque) of the Institute of Neuroscience in Brussels (UCL). My current projects aim at better understanding how the human brain computes action-based decisions. A first project focused on the contribution of the primary motor cortex to reinforcement learning and decision-making. A second project explored the cortical correlates of spatial attention and action selection during motor decisions. Finally, a third project investigated the motor cortical signatures of urgency during dynamic decision-making."
Deficient neural motor inhibition in alcohol-dependence.
Caroline Quoilin
Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
Caroline Quoilin
Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
Neural inhibition of the motor output pathway has emerged as a central aspect of healthy behavior. My talk will begin with a general overview of motor inhibitory processes in healthy subjects (as reviewed in Duque et al. Trends in Neurosciences 2017). It will then focus on a recent study in which we acquired neural inhibitory measures of motor activity in detoxified alcohol-dependent (AD) patients, using a standard transcranial magnetic stimulation (TMS) procedure whereby motor-evoked potentials (MEPs) are elicited in a choice reaction time task. Behavioral inhibitory aptitudes and trait impulsivity were also assessed in all participants. Finally, the patients were called back a year after the experiment to evaluate their relapse status and the potential relationship with motor inhibition. As expected, AD patients displayed poorer behavioral inhibition and higher trait impulsivity than controls. More importantly, the MEP data revealed a considerable shortage of motor inhibition in AD patients. Interestingly, this neural defect was strongest in the patients who ended-up relapsing during the year following the experiment. These data suggest a strong motor component in the neural correlate of altered inhibitory control in AD patients, as well as an intriguing relationship with relapse.