[Amygdaloid innervation of the frontal cortex in cats]

The amygdaloid complex has been reported to innervate the frontal cortex (prefrontal, premotor and motor cortex) in a variety of mammal species. We have investigated the topographic and laminar distribution of such projections in the cat by using anterograde and retrograde axonal transport of HRP and WGA-HRP. Premotor and medial prefrontal cortices, receive abundant projections from the basal magnocellular amygdaloid nucleus, while rostrolateral prefrontal or caudodorsal motor cortices are almost spared by amygdaloid projections. Striking differences are observed in the laminar patterns of distribution of amygdaloid axons in the various frontal areas. This selective areal and laminar distribution may entail noticeable functional dissimilarities. Possible roles of these neural networks and the concept of "limbic cortex" are discussed in view of these findings.