Participants were instructed to emphasize specific words in a sentence.

(A) Laryngeal anatomy. The vocal folds are stretched by the cricothyroid muscle, and increased tension in the vocal folds results in a higher produced pitch.

(B) Pitch-correlated neural activity at an example electrode. The speech waveform for one example sentence (emphasis on “I”) is shown at the top. Pitch contours (green lines) and single trial high gamma (HG) activation for the example electrode (black rasters) for every sentence spoken by a single participant are shown. Trials are grouped by the word of emphasis and co-aligned to the beginning of the emphasized word. On a single trial level, transient increases in neural activity are associated with pitch change.

(C) Spatial localization of electrodes that have a significant correlation with pitch, after controlling for supralaryngeal articulators. Electrodes cluster on the anterior aspect of the precentral gyrus in the dorsal laryngeal motor cortex (dLMC, located ventral to hand and dorsal to the lip cortical representations). The right hemisphere is shown, and the arrow indicates the example electrode in (B). We also observed feedback responses in parabelt auditory cortex on superior temporal gyrus (STG).

(D) Relationship between pitch and HG cortical activity across all significant electrodes in dLMC (mean and SD in gray, example electrode in black) over normalized pitch range. Activation increases monotonically with pitch values (middle 90 percentile range plotted).

(E) Correlation values for significant electrodes in the dLMC and auditory STG regions. Electrodes in dLMC were all positively correlated with the produced pitch of the emphasized word, whereas activity of STG electrodes were both positively and negatively correlated with pitch.

(F–H) dLMC activity shows both motor and auditory response properties. Temporal analyses show dLMC activity during speaking conditions precedes playback (listening) of the same utterances. (F) Pearson cross-correlation for the example electrode in (B) for speaking (green) and playback (purple). (G) Neural activation aligned to sentence onset for speaking (green) and playback (purple) conditions for the example electrode (mean ± SEM). (H) Average temporal offset of neural activation for each electrode in the dLMC with respect to sentence onset.