Figure 2.

Gamma-band LFP oscillations in the vStr form a dorsomedial to ventrolateral power gradient. A, Raw LFP traces from the recording electrodes at the dorsomedial (o), ventromedial (x), dorsolateral (*), and ventrolateral (#) points of the silicon probe for a representative low-gamma event. Gray bar spans the length of the gamma event (see Materials and Methods for details of gamma detection). B, Heat map showing gamma power (μV ²) across the recording array (64 sites, regularly spaced in an 8 × 8 grid spanning 1.4 mm²; see Fig. 1B for probe layout) during the same low-gamma event as seen in the raw traces. Gamma power is approximately five times greater in the ventrolateral site compared with the dorsomedial site. C, Average low- and high-gamma power across entire recording sessions (one each for subjects R1–R4; scale is normalized to the channel with the lowest power). Black spaces represent defective recording sites (see Materials and Methods for defective site criteria).