Contour integration in striate cortex. Classic cell responses or cooperative selection?

Psychophysics has established various rules of contour integration in gestalt perception. We tested the rule of good continuation by stimulating behaving monkeys with simple figures composed of Gabor patches, while recording from upper layer cells in visual cortex (V1). By decomposing these figures into their components and stimulating receptive field centers and surrounds separately with this stimulus set, we tested center-surround interaction for linearity.

Inter-cellular spike coincidences in visual detection tasks.

Synchronized spike activity is discussed as a possible representational code for object integration and as a neuronal basis of attention, perception and awareness. As a byproduct of experiments in which monkeys were trained to detect simple figures composed of single Gabor patches in a noisy background of similar elements, we found in special cases increased spike synchrony above chance level specifically related to figure detection. The long latency of this effect is difficult to interpret.