Over the last decade, the hypothesis has arisen that synchronization of cortical activity may represent a possible solution to the binding problem. The hypothesis remains controversial, with theoretical and experimental evidence in support and opposition. Despite several exciting recent findings, the definitive experiment remains to be done. This research project attempts to address the criticisms of past experimental findings by recording from multiple, spatially separated, single units in V1 of awake, behaving macaque monkeys, while the animals perform a two-alternative forced choice figure-ground segmentation task. The experiments will directly test the hypothesis that 1) increases and decreases in the salience of the figures are correlated to changes in the incidence and magnitude of neuronal synchronization, and 2) differences in the magnitude of neuronal synchronization may be observed between correct and incorrect trials. The stimuli will contain either one or two contours made up of aligned Gabor patches embedded in a background of randomly oriented and positioned Gabor patches. The behavioral task for the animals will be to signal the presence of one or two contours by directing their eye movements to the proper match stimulus presented on the screen after the stimulus is extinguished. The flexible nature of this stimulus allows the contours to be dynamically generated such that any cell isolated by the recording methods may be included in the analysis. The results of the experiments will provide definitive evidence to either confirm or reject the functional significance of neuronal synchronization, and provide insights into the neural architecture and circuitry that allows the brain to effectively solve the binding problem.
