Synaptic Interactions between Primate Precentral Cortex Neurons Revealed by Spike-Triggered Averaging of Intracellular Membrane Potentials In Vivo

摘要: To document synaptic interactions between neurons in the precentral cortex of macaque monkeys, we recorded vivo intracellular (IC) membrane potentials cortical simultaneously with extracellular (EC) action neighboring cells. The correlated EC spikes were obtained by spike-triggered averages (STA) IC for 373 cell pairs anesthetized and awake behaving monkeys. Sixty-three STAs (17%) showed excitatory postsynaptic (EPSPs), beginning after trigger spike. Pure EPSPs had onset latencies 0.9 ± 0.7 msec (mean SD) amplitudes 226 130 μV. Sixteen (4%) postspike inhibitory (IPSPs), 0.4 −274 188 most common waveform, observed 82% features, was a broad depolarization straddling spikes, reflecting synchronized input to both neurons. These average synchronous excitation (ASEPs) began 14.3 6.6 before spike 1064 867 Twenty-three (6%) an potential (ASIP): hyperpolarization IPSPs produced group local cells cell. ASIPs latency −5.5 2.7 amplitude −589 502 Combinations also observed. Successive recordings provided examples convergent divergent connections Neuron depolarizing (PSPs) STA yielded peaks cross-correlograms potentials; peak area proportional PSP. data suggest that significantly larger proportion interact through activity than simple serial interactions; moreover, affected more widely separated IPSPs, which seen often among closest