Figure 6

KX-dependent 80–130 Hz oscillations occur in the OB, but not thalamus or visual cortex of cats. (A) Example raw waveforms from one cat from three different brain regions. Raw signal is presented in top rows and 80–130 filtered signal is in bottom row. (B) Power spectrum from 10 min of recordings. We observed \(\sim\) 90 Hz distinct band in OB power spectra of all three cats (indicated on the power spectra by an arrow). In one cat with an electrode in the posterior OB the power of this rhythm was smaller (cat 1). There was no clear peak in the power spectra corresponding to this activity in the thalamus or visual cortex. There is separate y-scale for OB power (green, left) and for thalamus and visual cortex (red, right). Propofol anesthesia attenuated 80–130 Hz activity in the OB (insets, cat 2 and cat 3). (C) Modulation index score computed from single OB channels for all three cats. Color strength of the ’pixel’ represents power of the modulation for a given slow (driving frequency) and fast (modulated frequency) oscillation extracted from the raw signal. (D,E) show the rapid effect on OB oscillatory activity after supplementary infusion of KX, associated with increased power of the 80–130 Hz band with parallel decrease of the power of 30–65 Hz activity. The same phenomena were observed in rats; compare Fig. 1. (F) shows the effect of unilateral naris blockade of a cat which was associated with a reduction in 80–130 Hz power.