DENDRITIC CALCIUM CONDUCTANCES GENERATE HIGH-FREQUENCY OSCILLATION INTHALAMOCORTICAL NEURONS

Cortical-projecting thalamic neurons, in guinea pig brain slices, disp lay high-frequency membrane potential oscillations (20-80 Hz), when th eir somata are depolarized beyond -45 mV. These oscillations, preferen tially located at dendritic sites, are supported by the activation of P/Q type calcium channels, as opposed to the expected persistent sodiu m conductance responsible for such rhythmic behavior in other central neurons, Short hyperpolarizing pulses reset the phase and transiently increase the amplitude of these oscillations, This intrinsic thalamic electroresponsiveness may serve as a cellular-based temporal binding m echanism that sharpens the temporal coincidence of cortical-feedback s ynaptic inputs, known to distribute at remote dendritic sites on thala mic neurons.