Figure 2. Neural encoding of articulatory kinematic trajectories.

A, Magnetic resonance imaging (MRI) reconstruction of single participant brain where an example electrode is shown in the ventral sensorimotor cortex (vSMC). B, Inferred articulator movements during the production of the phrase “stimulating discussions.” Movement directions differentiated by color; positive X and Y (purple), negative X and Y (green) directions as shown in Figure 1A. C, Spatiotemporal filter resulting from fitting articulator movements to explain high gamma activity for an example electrode. Time 0 represents the alignment to the predicted sample of neural activity. Convolving the spatiotemporal filter with articulator kinematics explains high gamma activity D as shown by example electrode. High gamma from ten trials of speaking “stimulation discussions” were dynamically time warped based on the recorded acoustics and averaged together to emphasize peak high gamma activity throughout the course of a spoken phrase. E, Example electrode encoded filter weights projected onto midsagittal view of vocal tract exhibits speech-relevant articulatory kinematic trajectories (AKT). Time course of trajectories is represented by thin-to-thick lines. Larynx (pitch modulated by voicing) is one dimensional along y-axis with x-axis showing time course.