Figure 8.

Impact of lidocaine infusion in the perirhinal cortex on activity-dependent modification of neocortical responses induced by TFS applied at 1 (A) or 2 (B) neocortical stimulation sites. The schemes in the top panels illustrate the relative position of neocortical stimulating (St.) and area 36 recording electrodes (dots) located at proximity (C for close) or at a distance (D) from the stimulation site. Red asterisks mark the lidocaine infusion sites in area 36. (A1) TFS at one neocortical stimulation site. (B1) TFS at 2 neocortical stimulation sites. In this case, depending on the stimulating electrode considered, the same area 36 recording site was termed a close or distant site, hence the absence of C and D labels. After measurement of baseline response amplitudes, the same amount of lidocaine as in Figure 7C1 was infused at mid rostrocaudal perirhinal levels (red asterisks). Five minutes after concluding the infusion, TFS was applied at 1 (A) or 2 (B) neocortical stimulation sites. Panels 2 impact of neocortical TFS was then assessed after the lidocaine effect had dissipated (60-min postinfusion). Filled and empty bars show the results obtained in lidocaine and control experiments, at perirhinal recording sites close to (i.e., in rostrocaudal register) the neocortical induction sites or at distant sites (n = 8).