The thalamus is the major gateway for the flow of sensory information to the cerebral cortex. In early stages of sleep, when sensory perception drops, this structure is the source of robust network synchronized oscillations in the 6 to 14 Hz frequency range (spindle waves). We examine the role of these thalamic oscillations in the gating of synaptic inputs. We show that feedback inhibition from cells of the thalamic reticular nucleus controls spike transfer in thalamocortical cells in a state-dependant manner.
Neurons in the cerebral cortex are under a constant state of bombardment by synaptic potentials. We have used a computational model (Destexhe et al., 2001, Neurosci. 107:13) that mimics the synaptic bombardment of thousand of cells. This 'noise' injected in pyramidal cells reproduces the spontaneous activity recorded in the biological network in vivo or in vitro. Using the hybrid system, we can the test the impact of background synaptic activity on the probability of spike response to individual synaptic inputs.