title: NMDA receptor antagonist-enhanced high frequency oscillations: are they generated broadly or regionally specific?
abstract: Systemic administration of NMDA receptor antagonists, used to model schizophrenia, increase the power of high-frequency oscillations (130-180Hz, HFO) in a variety of neuroanatomical and functionally distinct brain regions. However, it is unclear whether HFO are independently and locally generated or instead spread from a distant source. To address this issue, we used local infusion of tetrodotoxin (TTX) to distinct brain areas to determine how accurately HFO recorded after injection of NMDAR antagonists reflect the activity actually generated at the electrode tip. Changes in power were evaluated in local field potentials (LFPs) recorded from the nucleus accumbens (NAc), prefrontal cortex and caudate and in electrocorticograms (ECoGs) from visual and frontal areas. HFO recorded in frontal and visual cortices (ECoGs) or in the prefrontal cortex, caudate (LFPs) co-varied in power and frequency with observed changes in the NAc. TTX infusion to the NAc immediately and profoundly reduced the power of accumbal HFO which correlated with changes in HFO recorded in distant cortical sites. In contrast, TTX infusion to the prefrontal cortex did not change HFO power recorded locally, although gamma power was reduced. A very similar result was found after TTX infusion to the caudate. These findings raise the possibility that the NAc is an important neural generator. Our data also support existing studies challenging the idea that high frequencies recorded in LFPs are necessarily generated at the recording site.
authors: Laboratory of the Limbic System, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw, Poland.
authors: Maciej
authors: M
authors: Olszewski
authors: Wioleta
authors: W
authors: Dolowa
authors: Pawel
authors: P
authors: Matulewicz
authors: Stefan
authors: S
authors: Kasicki
authors: Mark J
authors: MJ
authors: Hunt
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D058256:Brain Waves / Q000187:drug effects*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004567:Electrodes, Implanted; D004569:Electroencephalography; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D005583:Fourier Analysis; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013223:Statistics as Topic; D013779:Tetrodotoxin / Q000494:pharmacology
chemical_list: D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D026941:Sodium Channel Blockers; D013779:Tetrodotoxin; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate
keywords: Cortex; High frequency oscillations; Local field potential; NMDAR antagonist; Nucleus accumbens; Rat; Tetrodotoxin