Figure 4. Ipc is required for gamma oscillations in the sOT.

Conventions are as in Fig 3.

A) (Left) Evoked gamma oscillations (Top) were eliminated from the sOT when connections with the Ipc were transected (Bottom). (Right) Schematic illustrating transection of Ipc connections and recording configuration in sOT.

B) Power spectra of activity in the sOT in intact slices (grey) and in transected slices (black).

C) (Left) Gamma power in sOT in intact slices (Int) is abolished in transected (Ts) slices (intact=16 dB, transected=0 dB, p<0.01, U-test, n=10). (Right) Persistence of gamma oscillations in sOT is eliminated in transected slices (intact=332 ms, transected=0 ms, p<0.01).

D) (Left) Oscillations recorded in the sOT of intact slices were reversibly eliminated following focal application of the glutamatergic blocker CNQX to the Ipc. 0.5 mM CNQX was puffed for 0.5–1s at 5 PSI from a patch pipette above the slice in the Ipc. Puffs were administered such that bath flow was moving away from the OT, to prevent synaptic blockade of OT circuitry. (Right) Schematic illustrating focal puffing of CNQX into the Ipc and recording configuration in the sOT.

E) Both gamma duration and power in the sOT of intact slices were significantly reduced relative to control following application of CNQX to the Ipc (duration: 11.5% of control, p<0.001; power: 13.5% of control, p<0.001, Friedman test, n=5,); both recovered in 60% (n=3/5) of the sites