Figure 2.

Comparison of palatability representation in GC and EMG activity. A, Each intensity plot shows the frequency content (y-axis) of the mean EMG response as a function of time (x-axis) following delivery of one of the four taste stimuli (data averaged across 15 animals); brighter pixels indicate higher power. B, The left heat map depicts the rank correlation between taste palatability and EMG power (data averaged across 15 animals) for frequencies between 4 and 10 Hz across poststimulus time. Statistically significant correlations are plotted in blue or red (blue, negative; red, positive), with stronger color intensities indicating higher correlations. The right map shows the SE across sessions for each point in the correlation plot. C, Comparison of concurrently recorded neural and EMG responses following taste delivery. Both types of responses were smoothed with a 1 s rectangular window. Top, Each line represents the mean firing rate (y-axis) through poststimulus time (x-axis) of a representative GC neuron to one of the four taste stimuli: 300 mm, sS (dark red); 30 mm, dS (light red); 0.1 mm, dQ (light blue); and 1 mm, sQ (dark blue). The vertical dashed line indicates the earliest time at which the responses of the neuron were significantly correlated with taste palatability. Bottom, Same as above, but for the mean EMG power in the 4–6 Hz range. D, The fraction (y-axis) of GC neurons (n = 161; green line) and paired EMG (n = 20; black line) producing palatability-related responses as a function of time (x-axis) following taste delivery (error bars = SEM). The left edge of the gray box is aligned with the average onset time of the first gape following deliveries of sQ, as determined by the gape detection algorithm.