Selective inhibitory synapse loss in chronic cortical slabs: a morphological basis for epileptic susceptibility

Abstract

Electron microscopic examination of pyramidal neurones at the edges of chronic slabs of cerebral cortex in the cat revealed a selective loss of inhibitory (symmetric axosomatic) synapses compared with pyramidal neurones in the centers of the slabs. It appears likely that the neurons at the edges, which retain excitatory input (asymmetric axodendritic synapses) in the neuropil, but totally lack the somatic inhibitory input, act as the focus for the prolonged seizure activity which occurs in chronic cortical slabs.