It has long been known (since my dissertation – ahem) that repetitions of a visual stimulus result in reduced spiking activity of individual neurons. This is curious because repetition does not weaken the perception of the stimulus. If spiking of individual neurons alone is responsible for perception, why doesn’t the perception weaken? Brunet et al showed that stimulus repetition produces increases in gamma band synchrony (40-90 Hz) within and between higher and lower order visual cortical areas. The increased synchrony can maintain efficacy of signalling of the stimulus despite the decrease of neuron spiking. Gamma-band synchrony of the spikes increases in general but decreases for weakly driven neurons. Thus, stimulus repetition may prune the neural representation of a stimulus while increased gamma synchronization increases neuron signalling, resulting in a leaner and meaner stimulus representation. This lends further support for the role in gamma-band synchrony in bottom-up sensory processing (e.g., Buschman and Miller, 2007).
Further reading:
Buschman, T.J. and Miller, E.K. (2007) Top-down versus bottom-up control of attention in the prefrontal and posterior parietal cortices. Science. 315: 1860-1862 View PDF »
Incidentally, the effect of stimulus repetition on spiking activity was my first first-author publication:
Miller, E.K., Gochin, P.M., and Gross, C.G. (1991) A habituation-like decrease in the responses of neurons in inferior temporal cortex of the macaque. Visual Neuroscience 7:357-362.
Wutz et al used a visual forward-masking paradigm (mask then target) to study the neural basis of visual perception. The mask sometimes interfered with perception of the target. Higher beta power before the mask was associated with incorrect perception of the target. Evoked alpha phase reset was associated with correct target perception. This shows how oscillatory dynamics may play a role in carving successive visual inputs into separate perceptions.