Fig. 1.

Population responses in PPN. Left side. Population response recordings using low resistance (1–2 MΩ) electrodes in four individual slices containing the PPN shown in ERSP form. Recordings shown were collected from different slices. Briefly, exposure to CAR before (pre) TSA showed significant levels of activity in the beta/gamma range during the initial 10 min. After 10 min of TSA (not shown) it was discontinued, and CAR was superfused for another 10 min after TSA (post). In all cases, gamma frequency activity was reduced and lower frequency activity became more pronounced, at least in some cases, but not all. These results suggest that TSA reduced gamma band activity in the PPN network, despite being stimulated by CAR.