While the sequential activation of hippocampal place cells is evoked by locomotion of the animal, sequential spiking of visual neurons can be evoked by a moving stimulus sweeping across their receptive fields. Multielectrode recording VX-770 in the visual cortex of both anesthetized and awake rats showed that stimulation with a moving spot evoked sequential firing of an ensemble of neurons whose receptive fields fell along the motion path. After repeated stimulation with the moving spot, a brief light flash at the starting

point of the motion path evoked more sequential firing of these neurons similar to that evoked by the moving spot. Interestingly, in awake animals, this cue-triggered recall of spike sequence was observed during a synchronized quiet wakeful state, but not in a desynchronized active state (Xu et al., 2012), reminiscent of the hippocampal replay during quiet immobility (Diba and Buzsáki, 2007; Foster and Wilson, 2006; Karlsson and Frank, 2009). Together, these studies suggest that while the desynchronized brain state favors faithful representation of sensory inputs, the synchronized state may be more suited for either spontaneous or cue-triggered reactivation

of previous experience. Optimal control of behavior selleck chemicals llc depends on the integration of current sensory information with predictions based on prior experience. The relative weights of sensory and memory signals may be adjusted by changing the brain states through neuromodulatory inputs (Yu and Dayan, 2005). Studies over the last century have led to tremendous progress in our understanding of the neural control and functions of different states. Many key structures regulating brain states have been identified by measuring the effects of their disruption, and the firing

patterns of those neurons under different brain states have been characterized. A major new challenge is to dissect the microcircuitry within each structure and the long-range connections between them. These efforts will be greatly Astemizole facilitated by the newly developed optogenetic and circuit tracing tools. Functionally, the effects of vigilance and attention on sensory processing have been studied extensively through electrophysiological experiments in awake behaving animals. There is also accumulating evidence for the importance of synchronized brain states in learning and memory. Future studies combining the recording and selective manipulation of the reactivated memory traces should provide a definitive test of this hypothesis. We thank L. Pinto and D. Bliss for helpful discussions and comments on the manuscript. “
“The highly evolved neuronal networks of the dorsolateral prefrontal cortex (dlPFC) subserve working memory, our “mental sketch pad,” by representing information in the absence of sensory stimulation.