Influence of reward devaluation on striatal activity

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DESCRIPTION (provided by applicant): Our long-term objective is to advance the understanding of neurobehavioral systems and in particular, how neural systems produce goal-directed action. Goal-directed action is thought to be guided by a neural representation of the goal object. For a representation to guide the animal efficiently, it should access and use information concerning the internal state of the animal. The specific aim of the application is to study how reward devaluation influences striatal activity. The aim will be completed using in vivo electrophysiological recording of single striatal neurons while animals under different states of food satiation and deprivation perform instrumental discrimination tasks for different rewards. We focus on the striatum because this brain structure originally thought to be involved in general movement initiation and execution, is now believed to be involved in higher motor processing of reward information and production of goal- directed action. We believe the striatum is critical site of convergence for information regarding both external characteristics of the outcome with updates of the current internal state (i.e. hunger) to be used for motor output selection. A key component of the protocol is that we will utilize different prefeeding regimens to examine the different degrees of influence that internal state fluctuations can have upon behavior-related activity based on the similarity the prefeeding has with the expected reward outcome, these include 1) sensory-specific satiety. Here we prefeed the animal with one of the available outcomes in the testing situation 2) general satiety. Here we prefeed the animal with the food item normally delivered in the home cage setting and 3) food restricted with no prefeeding regimen. Differences in neural activity between the three prefeeding conditions for motor-related neural responses will support our hypothesis that behavior-related activity in the striatum gains access to and is influenced by alterations in motivational systems. We expect that the closer the relationship between the internal state change and learned properties of the available outcome, the greater the influence by these internal state deviations. The results have great implications for our understanding of basic mental operations that guide daily actions and in the treatment of mental health disorders characterized by emotional and behavior dysfunction. If we can pinpoint the different interactive influences at the neurobehavioral level that produce appropriate goal-directed action, then we can develop better treatments targeting pertinent neurobehavioral systems and more specifically, the intrinsic, integrative neural operations relevant to emotional and behavioral disorders.