Influence of Lesion Size and Location on Amphetamine-Facilitated Recovery of Beam-Walking in Rats

Amphetamine treatment facilitates recovery of beam-walking in rats with unilateral sensorimotor cortex lesions. Lesion extent was studied in amphetamine- and saline-treated rats selected for rapid and slow recoveries. Lesion volume, lesion depth, and the amount of medial cortex damage were not different among the 4 groups of rats. When the data were analyzed without regard to drug treatment, both lesion depth in rostral forebrain and maximum amount of medial cortex damage negatively correlated with recovery rate. Thus, lesion extent influences the rate of recovery of beam-walking in rats but does not explain the lack of effectiveness of amphetamine in selected animals.