Figure 3: Chronic effects of the NMDAR inhibitor ketamine on the theta state power spectrum.
From: Experience enhances gamma oscillations and interhemispheric asymmetry in the hippocampus
(a) Experimental design and CA1 s.r. theta LFP recordings. After weaning at postnatal day 21, rats were reared in ENR for 3 days to learn to drink from water bottles. Thereafter, the water was supplemented with ketamine (0.1% w/v) until the day of the recording (upper panel). Typical recording of bilateral theta-associated gamma oscillations from the CA1 s.r. of an ENR+ketamine (ENR+ket) rat. Left (L) and right (R) paired traces are wideband and slow gamma-filtered recordings, respectively (lower panel). (b) PSDs of the left and right CA1 s.r. theta state LFPs in ENR and ENR+ket conditions. The averaged PSDs were plotted as in Fig. 2b. (c) Mean R/L power ratios of theta (left panel), slow gamma (middle panel) and fast gamma (right panel) in CA1 s.r. of ENR and ENR+ket rats. The slow and fast gamma power ratios of ENR+ket were significantly lower than 1 (*P<0.05 and **P<0.01, respectively, t-test, NENR=10, NENR+ket=8). The ENR and ENR+ket power ratios were significantly different (***P<0.001, t-test, NENR=10, NENR+ket=8). Acute effect (within 90 min) of intramuscular ketamine administration (3.0 mg kg−1, ENR+a-ket, NENR+a-ket=4) on slow and fast gamma power is also shown in black in the middle and the right panel. ENR+a-ket did not show the inhibitory effects seen in ENR+ket. Error bars represent s.e.m.
