A Thalamocortical Neural Mass Model of the EEG during NREM Sleep and Its Response to Auditory Stimulation
Fig 8
Stimulation disturbs refractoriness.
The upper two panels depict the membrane voltages of the pyramidal and thalamic relay populations, respectively. In the third panel the conductivity of the Ih current is shown. (A) Example time series of an unperturbed train of SOs during sleep stage N3. The first two SOs lead to an activation of Ih, that slowly declines back to baseline levels. As Ih activation is still well above baseline, the third SO is unable to trigger a spindle response. During the fourth SO Ih activation is sufficiently low so that a spindle occurs. (B) Shown is an example of closed loop stimulation during sleep stage N3, with the dashed lines indicating stimulus onset. In contrast to the endogenous case, the depolarization of the thalamic relay population induced by the stimulation leads to a rapid decrease in Ih activation, so that the following SO triggers a spindle. Parameters as in Table 2.