Stimuli outside the classical receptive field modulate the synchronizationof action potentials between cells in visual cortex of cats

It is proposed that various attributes of an image are bound neuronally whe n responsive units fire in synchrony. Our investigations describe the influ ences of the contextual stimuli upon the occurrence of synchronization, in anaesthetized cats. Once a significant synchronization was recorded in the cross-correlogram (XCRG) between evoked action potentials of two groups of neurons in response to a drifting sine-wave grating, additional gratings we re positioned outside the compound receptive field. The synchronization str ength was then measured in relation to the difference between the orientati ons of the central and peripheral gratings. In the majority of cases result s indicate that the synchronization is facilitated with larger orientation disparities. Thus, our data support the notion that contrasting features of images facilitate synchrony of activity between neurons. NeuroReport 11:13 13-1317 (C) 2000 Lippincott Williams & Wilkins.