Light deprivation produces accelerated behavioral recovery of function from neglect produced by unilateral medial agranular prefrontal cortex lesions in rats.

Environmental manipulations involving 48 h of light deprivation have been found to produce sparing of function from neglect produced by unilateral destruction of the medial agranular prefrontal cortex (AGm) in rats. The present study is an extension of these findings and examined whether light deprivation would produce recovery in subjects with demonstrated severe neglect produced by unilateral AGm destruction. The orientation behavior of the subjects, 25 left and 16 right AGm operates, was tested at 4 h post injection and if severe neglect was demonstrated, the subjects were placed into one of three environmental conditions: (1) 48 h of total light deprivation, (2) 48 h of continuous light, or (3) 48 h of a 12:12 light/dark cycle. The left vs. right hemisphere comparisons indicated that the left hemisphere operates were significantly more responsive by 4 h postsurgery than the right hemisphere operates, and only five of the right hemisphere operates demonstrated severe neglect. Therefore, the effects of environment on behavioral recovery of function were only examined in left AGm operates with severe neglect. The results indicated that 48 h of light deprivation could produce dramatic behavioral recovery in left AGm operates with demonstrated severe neglect, and that these effects were not produced by disruption of the light/dark cycle.