Interaction between raphe dorsalis and nucleus basalis magnocellularis in the regulation of high-voltage spindle activity in rat neocortex

In the present study we compared the effects of an ibotenic acid lesion of the nucleus basalis magnocellularis (NBM), a 5,7-dihydroxytryptamine lesion of the raphe dorsalis (RD) and a combined RD and NBM lesion on the regulation of neocortical electrical activity in freely moving rat. NBM lesions (choline acetyltransferase decrease: frontal cortex 29%, occipital cortex 23%) increased both slow wave amplitudes and waking immobility-related high-voltage spindles (HVS). Although RD lesions (serotonin decrease: frontal cortex 67%, occipital cortex 68%) alone did not affect neocortical electrical activity, the lesion aggravated the increase of HVSs induced by an NBM lesion. The present results demonstrate an interaction between the RD and NBM in regulating cortical functions.