Fig. 7.

Spectral analysis of somatosensory and chemosensory responses, computed using the fast Fourier transform. For each plot, the abscissa is frequency, and theordinate is normalized power, rescaled to have a mean of 0 and SD of 1. A, The averaged spectra of all the neurons recorded during the somatosensory cortex sessions (dashed line) and of all the neurons recorded during the gustatory cortex sessions (solid line). Note the excess of power in the 5–10 Hz range, present in the somatosensory cortical recordings and absent in the gustatory cortical recordings.B, Similarly constructed average spectra taken exclusively from GC recordings. Shown are the spectrum of neurons with taste-specific responses (solid line), the spectrum derived solely from cells with early somatosensory responses (dashed line), and the spectrum derived solely from cells with late responses (dot-dash line).