State Dependency of Visual Thalamic and Cortical Activities

Abstract

This section deals with the functional modes of thalamic neurons during the EEG-desynchronized states of wakefulness and REM sleep, as opposed to the state of sleep with EEG synchronization. The rhythmic oscillations of thalamic cells’ membrane potential during EEG-synchronized sleep are accompanied by a depressed transfer function, whereas the stabilized membrane potential and tonic firing of thalamic neurons during EEG-desynchronized behavioral states are associated with secure synaptic transmission of incoming signals. The basic events in the visual thalamus are not different from those in other thalamic territories. To a large extent, the activities of neocortical neurons during various states of vigilance are dependent on fluctuations of excitability at the thalamic level.