Electrophysiological evidence that a set of interfascicular cells of the rat anterior commissure are neurons.

摘要

In mammals, the anterior commissure (AC) provides a route that interconnects homonymous areas of the basal forebrain. Recently, we reported the presence of short-axon and projection neurons among the axonal fascicles of the rat AC (i.e. interfascicular neurons; IFNs). This, coupled with the commissural inputs to these neurons, suggests that in addition to conveying nerve impulses, the AC may be a site of neural processing. To test this hypothesis, the electrophysiological activity of IFNs was recorded in adult albino rats. From extracellular recordings performed in 11 IFNs, it was found that these cells: (1), have a spontaneous discharge of a relatively low frequency (i.e. 0.04 +/- 0.1 to 5.9 +/- 3.2 spikes per second); (2), application of anodic current in the adjacent commissural fibers decreased this frequency; and (3), application of cathodic current increased the number of action potentials. Since observations made in Golgi-impregnated sections suggest that the main input to IFNs arises from their commissural collaterals, it is concluded that these cells may participate in the integration of interhemispheric nerve impulses.