Data from: Dopaminergic lesions of the dorsolateral striatum in rats increase delay discounting in an impulsive choice task

Dysregulated dopamine transmission in striatal circuitry is associated
with impulsivity. The current study evaluated the influence of
dopaminergic inputs to the dorsolateral striatum on impulsive choice, one
aspect of impulsive behavior. We implemented an operant task that measures
impulsive choice in rats via delay discounting wherein intracranial
self-stimulation (ICSS) was used as the positive reinforcer. To do so,
rats were anesthetized to allow implanting of a stimulating electrode
within the lateral hypothalamus of one hemisphere and bilateral dorsal
striatal injections of the dopaminergic toxin, 6-OHDA (lesioned) or its
vehicle (sham). Following recovery, rats were trained in a delay
discounting task wherein they selected between a small ICSS current
presented immediately after lever pressing, and a large ICSS current
presented following a 0 to 15s delay upon pressing the alternate lever.
Task acquisition and reinforcer discrimination were similar for lesioned
and sham rats. All rats exhibited an initial preference for the large
reinforcer, and as the delay was increased, preference for the large
reinforcer was decreased indicating that the subjective value of the large
reinforcer was discounted as a function of delay time. However, this
discounting effect was significantly enhanced in lesioned rats for the
longer delays. These data reveal a contribution of dopaminergic inputs to
the dorsolateral striatum on impulsive choice behavior, and provide new
insights into neural substrates underlying discounting behaviors.