Recurrent synaptic input and the timing of gamma-frequency-modulated firing of pyramidal cells during neocortical "UP" states.

Gamma (gamma) oscillation, a hallmark of cortical activity during sensory processing and cognition, occurs during persistent, self-sustained activity or "UP" states, which are thought to be maintained by recurrent synaptic inputs to pyramidal cells. During neocortical "UP" states, excitatory regular spiking (RS) (pyramidal) cells and inhibitory fast spiking (FS) (basket) cells fire with distinct phase distributions relative to the gamma oscillation in the local field potential. Evidence suggests that gamma-modulated RS --> FS input serves to synchronize the interneurons and hence to generate gamma-modulated FS --> RS drive.

Generalized synchronization of spatiotemporal chaos in a liquid crystal spatial light modulator.

We demonstrate generalized synchronization in a spatiotemporal chaotic system, a liquid crystal spatial light modulator with optoelectronic feedback.