Figure 1. Thalamic spindle-burst oscillations are transmitted to visual cortex.
(A) Experimental setup. Simultaneous recordings from visual thalamus (lateral geniculate nucleus, LGN) and primary monocular visual cortex (VC) were acquired with two single shank multi-electrode arrays in awake, head-fixed rats. (B) Reconstructed electrode track in LGN. Scale bar: 100 µm (C) Representative spontaneous activity in LGN of a P10 rat. Raster plot shows multi-unit spiking (MUA) from contacts separated by 50 µm. Eye specificity of each channel is shown by box on left. Spike spectrogram shows frequency of MUA modulation for LGN channel with maximal contralateral visual response (rectangle at 0 µm). Long-duration spiking events previously shown to result from retinal waves (Colonnese and Khazipov, 2010), marked by grey shadding, are associated with elevation in beta-band frequencies in LGN and VC, referred to a spindle-burst oscillations. (D) Representative spontaneous activity in VC simultaneously recorded with (C). Raster plots show MUA at multiple depths. Local field potential (LFP) recording in L4 is plotted on LFP-derived spectrogram. Elevations in beta-band frequencies (spindle-bursts) are associated with similar activities in LGN. Scale bar is 200 µV. (E) LFP (1–150 Hz) and MUA (>300 Hz) in LGN and VC during the retinal wave shown in (C) and (D) at expanded time scale. (F) LGN MUA (>300 Hz) and VC LFP (1–150 Hz) during a retinal wave shown in (E) at expanded time scale. (G) Population mean of normalized LGN spike spectra for P9-P11 (n = 7). Grey shading is standard error of the mean. (H) Population mean of normalized VC LFP spectra for P9-P11 (n = 7).