Abstract
Abstract: :
Purpose: Spike-timing-dependent synaptic plasticity has been characterized at various central synapses in vitro. In this work we study the importance of timing of visual stimuli in modification of the functional connectivity between cortical neurons in vivo. Methods: Asynchronous visual stimuli were applied to two adjacent retinal regions of adult cats with intervals between 8.3 and 66.7 ms. The responses of pairs of neurons (n=589) in V1 were recorded extracellularly with a 4x4 tetrode array (U of Michigan) and shuffle-corrected crosscorrelograms were computed between each pair. Results: During conditioning, the cells exhibited precise time-locking of their spikes to the flashed stimuli. The conditioning also induced a change in synaptic connectivity between cortical cells whose receptive fields fell in the two retinal regions, as reflected in the crosscorrelograms, as either a lateral shift or a change in the amplitude of the peak (n=26...138). These changes depended on the order and interval between stimuli in the two regions, in a manner consistent with spike-timing-dependent synaptic plasticity observed in vitro. The effects decayed within 10 minutes in absence of further conditioning (n=30...89). Conclusion: Timing of visual stimuli can play a critical role in experience-dependent cortical plasticity, probably through spike-timing-dependent synaptic plasticity.
Keywords: 520 plasticity • 394 electrophysiology: non-clinical • 621 visual cortex