[Cholinergic structures in the auditory area of the cerebral cortex in the cat (zone AI)]

Histochemical reaction to AChE was used to reveal the network of cholinergic varicose fibres in the neuropile of different cortical layers. Its density was maximal in layer I and deeper, and minimal in layers II and III. Among neurons of zone AI few stellate neurons located in layers II-VI are cholinergic. Axons of some stellate neurons terminate on adjacent neurons, axons of a part of layer VI neurons travel to the subcortical layer of the associative arcuate fibres. Cholinergic terminals are located on the soma and proximal parts of dendrites of neurons most of which contain no acetylcholinesterase. Such cholinoceptive neurons of various size and shape are found in all cortical layers.