Figure 2: Self-initiation bidirectionally modulates evoked responses in the auditory cortex.

(a) Example recordings from an isolated neuron in the auditory cortex. Left inset, spike waveform average and s.e.m. (grey shadow); horizontal scale bar, 0.4 ms and vertical scale bar, ∼40 μV. Raster plots (top) and z-score PSTHs (bottom) of recordings performed during uncued and self-initiated trials, aligned either to target tone onset (red bar) or to non-target tone (gray bar). For this example cell, responses to target and non-target tones were suppressed during self-initiated trials. (b) Example recordings from a cortical neuron for which responses to target tones were enhanced during self-initiated trials. (c) Example recordings from an isolated neuron in the auditory cortex for which responses to non-target tones were enhanced during self-initiated trials. (d) The distribution of the modulation index calculated for all 117 recorded neurons during target or non-target presentation, ordered in an ascending manner from left to right. Compared with responses during uncued trials, target-evoked responses were suppressed in 74/117 (63.2%) neurons and enhanced in 43/117 neurons. Non-target evoked responses were suppressed in 73/117 (62.4%) and enhanced in 44/117 neurons. (e) The z-score difference shows similar trends, where 68.7% of neurons had smaller target response z-score during self-initiated trials and 65% of neurons had smaller non-target response z-score during self-initiated trials. (f) Example cell z-score PSTHs during self-initiated trials and during correct uncued trials as well as error uncued trials. Grey bar, non-target tone. (g) The distribution of modulation indices for target and non-target frequencies, calculated for ‘Self’ versus ‘Uncued’ trial and for ‘Self’ versus ‘Correct Uncued’ trials. Error bars are s.e.m.