Functional recovery and dendritic hypertrophy after posterior and complete cingulate lesions on postnatal day 10

Rats received lesions of the posterior cingulate cortex or both the anterior and posterior cingulate cortex (total cingulate), or sham procedures, on postnatal Day 10. As adults, animals were trained in the Morris water task. Both the cingulate lesion groups showed substantial functional recovery relative to our previous studies of adult operates or animals with perinatal cingulate lesions. A Golgi analyis of layer III pyramidal cells in parietal cortex showed an increase in dendritic length in the lesion animals relative to sham controls, which is similar to previous findings for rats with anterior cingulate but not motor or parietal lesions. In addition, there was a partial regeneration of the anterior tissue in the total cingulates, which in some cases extended into the posterior region. This is consistent with earlier findings that anterior cingulate lesions around Day 10 stimulate neurogenesis. It appears that there is something special about the reparative processes and subsequent functional recovery that follow midline neocortical lesions.