Grant: Discovery Grants Program - Individual

As early as Pavlov's original conditioning experiments in which dogs began to salivate to the sound of a buzzer that had been associated with the imminent arrival of food researchers noticed that some animals attempted to ring the buzzer in order to obtain food. The same behaviour can be observed in other species. In rats, a non-functional lever presented to the animal before receiving food will cause some animals to press the lever, a behaviour known as "sign tracking". Other animals go for the food distributor (goal tracking), or alternate between these two behaviors. These individual approach styles correlate with other phenotypesthe sign tracker animals have poor attention control, a propensity to addiction and a greater probability of drug relapse. These individual styles of behaviour are observed in other species, including humans, in which sign tracking is linked to obesity. Animals who engage in sign tracking have several neurological differences, in particular to their dopaminergic reward system (D2 and D3 receptors, DAT). Although acetylcholine is a neurotransmitter whose function is related to attention, this neurotransmitter exerts some control on the dopaminergic system and may be involved in sign-tracking behaviour. Only a few studies have examined the role of acetylcholine in the individual style behaviour. Since sign tracker rats are known to show attentional deficits that are acetylcholine dependent, we suspect a weaker control by the acetylcholine system. Acetylcholine is largely overlooked; its study is a fundamental interest since it is known to control factors of reward. My innovative research program aims at better understanding the role of acetylcholine in reward valuation and individual differences in approach style. To define the acetylcholine role in the individual approach style, three specific objectives are proposed. 1- We will identify the role of the differents parts of the cholinergic system on the individual approach style by lesioning 3 different acetylcholine areas of the brain (top-down attention, bottom-up attention and reward system). 2- We will evaluate the electrophysiological (ERP) differences according to the individual approach style. 3- We will quantify the neuroanatomical differences from the sign tracker and goal tracker animals, in the three regions aforementioned in objective 1. Overall, these findings will provide new knowledge about the origins of the individual approach style and are especially important since these animals also show deficits in attention, vulnerability to drug dependence and greater susceptibility to relapse. The role of acetylcholine in the individual approach style is a great new vista leading to a better understanding of addiction, attention control and their comorbidity.