Figure 2From: Plumes of neuronal activity propagate in three dimensions through the nuclear avian brainPropagating slow-waves in the zebra finch forebrain. (A) This is an expanded five-second recording showing the temporal pattern of local field potential (LFP) and analogue multiunit activity (AMUA) (Bird 6, horizontal plane, and electrode site column 6, row 4 from FigureĀ 2B). (B) The same five-second example as in FigureĀ 2A as recorded across the 8āĆā8 grid of electrode sites, showing that oscillations appear to be globally distributed. (C) Detail of the LFP and AMUA peak indicated with two asterisks in FigureĀ 2B, showing that peak activity occurs at slightly different times in different sites. (D) This is the same peak event as in FigureĀ 2C, now visualized in a sequence of image plots, where each image has 8āĆā8Ā pixels corresponding to the 8āĆā8 grid of electrode sites, and where pixel color and gray levels correspond to LFP and AMUA magnitudes. The peak of the waveform plots in FigureĀ 2C now appears as a propagating plume of activity. (E) The AMUA time lag of peak activity for three sites, each relative to the other sites, expressed in an 8āĆā8 matrix of image pixels that correspond to the site positions in the electrode grid. Time lags are calculated as the lag of maximum cross-correlation, with cross-correlation lags ranging from ā50 to +50Ā ms. See text for more explanation. (F) The mean lag of an electrode site relative to the other sites (mean of nā=ā63). Each pixel is the mean of the values as shown in an 8āĆā8 matrix in FigureĀ 2E. (G) LFP plume propagation across the grid is tracked by calculating the spatial average of the plume in 1-ms intervals, based on sites with a potentialā<āā0.25Ā mV. Cross hairs indicate plume spatial average for a selection of 12 1-ms time intervals.Back to article page