Time-dependent changes in amphetamine self-administration following frontal cortex ablations in rats.

Conducted 2 experiments with a total of 28 operated, 25 sham-operated, and 21 normal female Sprague-Dawley albino rats. Ss were trained to intravenously self-administer dextroamphetamine (.01 mg/kg per reward infusion) during daily 1-hr testing sessions. Following removal of frontal cortex, rates of dextroamphetamine self-administration were higher at early (3-5 days) postoperative intervals but lower at later (2-4 wks) postoperative intervals. These and other results indicate that, as a function of time after surgery, frontal Ss were first hyposensitive and then became increasingly hypersensitive to the rewarding effect of dextroamphetamine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)