Functional synaptic organization of primary visual cortex neurones in the cat.

摘要: The spontaneous and light evoked post-synaptic activity of cells the primary visual cortex was investigated with intracellular quasi-intracellular records. resting membrane potential fluctuated mostly between 3–10 mV below firing threshold owing to EPSP- IPSP-activity. Discharge therefore low. Forms amplitudes visible EPSP's showed a large variability, frequency 150–300/sec. Discrete IPSP's were 0.5–3 less frequent than (about 1∶10). Their duration only slightly longer that EPSP's. could be elicited at on or off by appropriately positioned small stimuli. During initial reaction following stimulus, single PSP's distinguished. Geniculate on-center- as well off-center-afferents lead excitation inhibition in different neurones. receptive fields cortical monocular stimulation analysed averaged In each neurone 2–4 overlapping areas on- off-activation -inhibition Each these activation zones had functional properties geniculo-cortical onor off-center fibre their field centers separated 1–3°. variety organizations neurones explained variable combinations converging geniculate fibres either excitatory inhibitory action overlap fields. This tested simple computer model. — Most pronounced reactions movement direction specific sensitivity half investigated) an contact fibre, which seemed mainly responsible for reaction.- findings suggest from eye 5 afferent have major effect one cell. Inhibitory afferents may indirect relayed through another pyramidal