From habits to compulsions: the role of glutamate and serotonin in obsessive compulsive disorder

This proposal aims to understand why and how humans lose control over behaviour. Two distinct neural systems are thought to interact to control behaviour: the goal-directed system, supporting intentional behaviours, and the habitual system that underlies  automatic actions. These two systems should be in appropriate dynamic balance. Compulsivity is thought to arise from an imbalance in this interaction, causing patients to rely more on habit. 

I will characterise how and where the brain decides between intentional and automatic actions  after habits are established. The aim is to describe how a healthy brain breaks habits and a compulsive brain shifts from habits to compulsions. I will use different experimental conditions to examine how distinct motivational signals affect these choices, investigating whether fear prevents or enables participants to break habits in optimal ways. I will also investigate whether the abnormal imbalance towards the habit system observed in compulsive disorders is caused by a loss of control in frontal brain areas and whether this relates to abnormalities in the concentrations of three major brain chemical neurotransmitters: glutamate, GABA and serotonin.

The findings of the study can be used to develop new therapies to help patients resist compulsions.