Intracortical connectivity revealed by spike-triggered averaging in slice preparations of cat visual cortex

Intracortical connectivity was studied in slice preparations of cat's visual cortex by spike-triggered averaging. The experiments documented the unitary postsynaptic potentials underlying the inhibitory and excitatory connections from layer III-IV border cells to supragranular cells, as demonstrated previously by cross-correlation studies. In addition the analysis demonstrated the existence of two excitatory connections, between supragranular and layer V cells, that were not detectable in previous cross-correlation studies.