Eric Hoskins

Cognitive flexibility is the ability to learn and unlearn behaviors. This trait is rapidly gaining attention and impairment of cognitive flexibility is associated with various neuropsychiatric disorders including obsessive compulsive disorder and depression. Our lab has attempted to enhance cognitive flexibility in animal models using deep brain stimulation of the mid striatum (an area homologous to the human ventral striatum) of Long Evans rats. We found that stimulation did increase cognitive flexibility as assessed using a cognitive set-shifting task. However, it was unclear by what mechanism stimulation was improving task performance. I investigated rat behavior in the intertrial intervals within set-shift where the behavior of the rats is uncued and unrewarded. To do this, I analyzed data from our set-shift experiments in Python to identify the structure of poking in the ITI. This guided further analysis and allowed me to categorize pokes based on underlying behavioral indications. From this, I was able to isolate the effect of a subset of ITI pokes on task performance and used a generalized linear model to identify the contribution of this effect, which was enhanced by stimulation, to the overall stimulation effect on task performance. Ultimately, differences in this ITI behavior between rats receiving stimulation and sham could explain a significant portion of the overall effect of stimulation on task performance and cognitive flexibility. This is important because it indicates that part of the effect of mid striatal stimulation is to increase the tendency of rats to actively engage in precommitment to responses before a choice is offered.