Figure 2.

Similar temporal activity patterns initiated by presentation of tones and natural sounds. (A) Raster plots showing spike times for two representative neurons to repeated presentations of a pure tone stimulus. (B) Average activity of 90 simultaneously recorded neurons to tone stimuli. Grey bars show pseudocolor representations of each neuron’s perievent time histogram (PETH), red dots denote each neuron’s mean spike latency in the 100ms after tone onset. Neurons are ordered vertically by the mean latency over all stimuli, to illustrate sequential spread of activity. (C) Response of the same two neurons as in (A) to a natural sound (insect vocalization; sound spectrogram shown below rasters), illustrating similar temporal response profiles as to the tone. (D) Response of the same population as (B), displayed in the same vertical order, indicating that the sequential order of firing is preserved. The dots on the right indicate at which shank neurons were recorded. (E) Scatter plot showing each neuron’s mean spike latency for tones and natural sounds with putative interneurons marked in blue. The distribution of points along the diagonal indicates preservation of sequential structure across conditions. (F) Histogram of rank correlations between mean spike times for individual tone presentations and mean response profile across all tones (see Supplementary Figure 4A). (G) Histogram of rank correlations between mean spike times for single natural sound presentation and average across all tones. The prevalence of positive correlations indicates that for the majority of trials, the sequence of neuronal activation was preserved.