Fig 2. Neural recordings.

(A) MRI-based volume renderings of the skull and target brain regions. Top panel shows the arrangement of the two chambers. Two bottom rows show segmented brain regions within the cranial window of each chamber, for each monkey. Region boundaries were assigned based on [28]. Red—somatosensory cortex; blue—primary motor cortex (M1); pink—dorsal premotor cortex (PMd); green—ventral premotor cortex; white—frontal eye field. CS—central sulcus; SPCD—superior pre-central dimple; ArS—arcuate sulcus. Grey ellipses indicate regions sampled by recordings. (B) Interlaminar recordings were obtained using V- and S- probes (Plexon, Inc., Dallas, TX) with 24–32 electrodes aligned perpendicular to the cortical surface. Example waveforms were all simultaneously recorded from a single probe. (C) MRI coronal slice, monkey O. 3mm black bar is approximately equal to the distance spanned by electrodes on 32-channel probes. Same landmark labels as in (A).