Behavioral endophenotypes of chronic unpredictable stress

Abstract

Stress is the response to a perceived or real threat. Acute incidences of stress can be beneficial. However, repeated stress can cause maladaptive changes in brain and behavior leading to neuropsychiatric illnesses. Among publications on chronic stress, only recently has its effects on decision-making been identified. I have designed a competitive choice task (CCT) to measure changes in decision-making. Decision-making behaviors in this task are governed by the dorsal lateral striatum, ventral striatum and medial prefrontal cortex. These behaviors that these structures mediate are lose-shift, win-stay, and extraneous feeder sampling, respectively. I find that chronic unpredictable stress increases win-stay behavior strategies, decreases extraneous feeder sampling and increases speed but does not affect lose-shift strategies. Chronic stress, therefore, increases activity within the ventral striatum and decreases activity within the medial prefrontal cortex.