Figure 2.

Selection of candidate waveforms for neurometric analyses. A, Raw waveform of a neural response to AM noise (blue envelope) during task engagement. Candidate waveforms were >4 SDs above noise floor (red line). B, PCA plot in which two waveform clusters are separated (red and green), both while an animal is engaged (left) or disengaged (right). Insets show raw waveforms (gray lines) and averages (red line) for red cluster. C, Example raster for unit shown in B. Gray shaded area indicates period when stimulus was present. D, Coronal section shows an electrode track (arrow), with staining for wisteria floribunda agglutinin to reveal the primary auditory cortex.