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 b een found to produce sparing of function from neglect produced by unil ateral 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 dem onstrated severe neglect produced by unilateral AGm destruction. The o rientation behavior of the subjects, 25 left and 16 right AGm operates , was tested at 4 h post injection and if severe neglect was demonstra ted, the subjects were placed into one of three environmental conditio ns: (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 hemispher e comparisons indicated that the left hemisphere operates were signifi cantly more responsive by 4 h postsurgery than the right hemisphere op erates, and only five of the right hemisphere operates demonstrated se vere neglect. Therefore, the effects of environment on behavioral reco very of function were only examined in left AGm operates with severe n eglect. The results indicated that 48 h of light deprivation could pro duce dramatic behavioral recovery in left AGm operates with demonstrat ed severe neglect, and that these effects were not produced by disrupt ion of the light/dark cycle.