We have shown previously that the NMDAR antagonists ketamine and MK-801 enhance high-frequency oscillations (140– 180 Hz, HFO) in the rat nucleus accumbens (NAc). However, it is not known whether NMDAR antagonists can modify HFO recorded in structures outside the NAc. Thus we have examined the effect of a single subanesthetic dose of ketamine (25 mg/kg) on oscillatory activity in local fi eld potentials recorded in the neuroanatomically related dorsal striatum and in the hippocampus, where spontaneous high-frequency oscillations (ripples) have been well described. We used both monopolar and bipolar recordings to evaluate oscillatory activity recorded at baseline and after injection of ketamine. In monopolar recordings ketamine-induced increases in the power of HFO were present in all structures, although the power was always substantially larger in the NAc. Bipolar recordings, known to remove common-mode input, were used in an attempt to more precisely localise the source of HFO. In all cases ketamine-induced HFO were still present in the signals recorded from the NAc, but not from the dorsal striatum or hippocampus. Notably, spontaneous sharp-wave ripples also remained in the bipolar signal from the hippocampus. In a separate study of the depth-profi le analysis of oscillatory activity we found the power of HFO was substantially larger in areas closest to the NAc. These fi ndings suggest that ketamine may produce some regionally specifi c changes in HFO.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.