Synchrony and the binding problem in macaque visual cortex

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“Synchrony and the binding problem in macaque visual cortex” by Y. Dong, R. von der Heydt, and E. Niebur. In Society for Neuroscience Annual Meeting, (Washington, DC), 2006.

Abstract

Neural synchrony has been proposed as a solution to the binding problem. To test this hypothesis, we analyzed single-unit activity recorded from 32 pairs of neurons in cortical areas V1 and V2 of two awake behaving monkeys (Macaca mulatta). We also characterized neurons in terms of border ownership properties (Zhou et al., J Neurosci 20: 6594, 2000). Animals performed a fixation task while two types of stimuli were presented in parafoveal vision. One was a quadrilateral with two of its edges in the classical receptive fields of the two neurons under study. The other stimulus consisted of two non-overlapping rectangles that were positioned such that they produced exactly the same edges in these receptive fields as the single quadrilateral. The local contrast in the receptive fields was also identical. The hypothesis to be tested was whether representation of the same visual object by two neurons, as in the first case, makes them fire more synchronously than in the second case when they represent different objects. We tested this hypothesis by analyzing the correlation structure of the spike trains generated in these two conditions. In cell pairs in which both members were modulated by border ownership we found increased synchrony between the one-object (binding) condition compared with the two-object condition. No increased synchrony was found in the other cell pairs. We attribute the synchronization in border ownership sensitive pairs to common input from "grouping cells" which have been postulated in a recent model to explain border ownership selectivity (Craft et al., J Vision 4:728, 2004). Grouping cells integrate co-circular edge signals and enhance the gain of the corresponding edge cells by feedback, thus imparting them with border ownership selectivity. The model predicts that synchronization should occur between border ownership cells, but not between other cells in visual cortex. In summary, synchronization tends to occur between border ownership selective cells. A plausible explanation is common input from neurons involved in figure-ground organization NSF-CRCNS/NIH-NEI 5R01EY016281-02 NIH R01 EY02966

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BibTeX entry:

@incollection{Dong_etal06,
   author = {Y. Dong and R. von der Heydt and E. Niebur},
   title = {Synchrony and the binding problem in macaque visual cortex},
   booktitle = {Society for Neuroscience Annual Meeting},
   pages = {734.8},
   publisher = {Society for Neuroscience},
   address = {Washington, DC},
   year = {2006}
}