Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4354263 | Trends in Neurosciences | 2014 | 13 Pages |
•Complex visual scenes are converted to a temporal code: a ‘to-do list’.•The order of the temporal code is determined by bottom-up and top-down drives.•Phase-coding organized by alpha oscillations coordinates competing representations.•Gamma activity phase-coupled to alpha oscillations segments competing representations.
Sensory systems must rely on powerful mechanisms for organizing complex information. We propose a framework in which inhibitory alpha oscillations limit and prioritize neuronal processing. At oscillatory peaks, inhibition prevents neuronal firing. As the inhibition ramps down within a cycle, a set of neuronal representations will activate sequentially according to their respective excitability. Both top-down and bottom-up drives determine excitability; in particular, spatial attention is a major top-down influence. On a shorter time scale, fast recurrent inhibition segments representations in slots 10–30 ms apart, generating gamma-band activity at the population level. The proposed mechanism serves to convert spatially distributed representations in early visual regions to a temporal phase code: that is, ‘to-do lists’ that can be processed sequentially by downstream regions.