The spindle oscillations in the thalamic reticular nucleus, auditory thalamus, and cortex

Abstract

In the present study, we investigated the spindle oscillation in the thalamic reticular nucleus (TRN), the auditory thalamus, and the cortex. Neuronal activities in above regions were simultaneously recorded with extracellular and intracellular electrodes. Spindle-like oscillation was recorded in the TRN, medial geniculate body (MGB) and auditory cortex (AC). With cerveau isolé preparation, a rhythmic and synchronized activity was recorded from the TRN, MGB and AC, where a spindle frequency could be found. The MGB showed inhibitory postsynaptic potentials (IPSP) with spindle frequency. The IPSP oscillation was not accompanied with low-threshold calcium spikes (LTS) in spindle frequency. In the anesthetized guinea pigs with intact brain, spindle oscillations consisted of excitatory postsynaptic potentials (EPSP) with spikes were recorded in the MGB. Spindle oscillation in the MGB, TRN and AC could be triggered and synchronized by repeated acoustic stimuli and repeated electrical stimulation of the AC. The occurrence of the EPSP spindles in the MGB was accompanied with spindle waves in the AC. The spindle oscillations among the TRN, MGB, and AC were further analyzed using cross-correlation, and explored after ablation of the AC, ablation of the MGB, inactivation of the TRN. Our results proposed that the spindle oscillation could be also initiated in the MGB and cortex, other than the TRN.