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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Network Asynchrony Underlying Increased Broadband Gamma Power

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Guyon, Nicolas [1] ; Zacharias, Leonardo Rakauskas [2] ; de Oliveira, Eliezyer Fermino [3, 4] ; Kim, Hoseok [1] ; Leite, Joao Pereira [2] ; Lopes-Aguiar, Cleito [5] ; Carlen, Marie [1, 6]
Total Authors: 7
[1] Karolinska Inst, Dept Neurosci, S-17177 Stockholm - Sweden
[2] Univ Sao Paulo, Ribeirao Preto Med Sch, Dept Neurosci & Behav Sci, BR-14049900 Ribeirao Preto - Brazil
[3] Univ Fed ABC, Ctr Math Comp & Cognit, BR-09606070 Sao Bernardo Do Campo - Brazil
[4] Albert Einstein Coll Med, Dominick P Purpura Dept Neurosci, Bronx, NY 10461 - USA
[5] Univ Fed Minas Gerais, Inst Biol Sci, Dept Physiol & Biophys, BR-31270901 Belo Horizonte, MG - Brazil
[6] Karolinska Inst, Dept Biosci & Nutr, S-14183 Huddinge - Sweden
Total Affiliations: 6
Document type: Journal article
Source: JOURNAL OF NEUROSCIENCE; v. 41, n. 13, p. 2944-2963, MAR 31 2021.
Web of Science Citations: 6

Synchronous activity of cortical inhibitory interneurons expressing parvalbumin (PV) underlies expression of cortical gamma rhythms. Paradoxically, deficient PV inhibition is associated with increased broadband gamma power in the local field potential. Increased baseline broadband gamma is also a prominent characteristic in schizophrenia and a hallmark of network alterations induced by NMDAR antagonists, such as ketamine. Whether enhanced broadband gamma is a true rhythm, and if so, whether rhythmic PV inhibition is involved or not, is debated. Asynchronous and increased firing activities are thought to contribute to broadband power increases spanning the gamma band. Using male and female mice lacking NMDAR activity specifically in PV neurons to model deficient PV inhibition, we here show that neuronal activity with decreased synchronicity is associated with increased prefrontal broadband gamma power. Specifically, reduced spike time precision and spectral leakage of spiking activity because of higher firing rates (spike ``contamination{''}) affect the broadband gamma band. Desynchronization was evident at multiple time scales, with reduced spike entrainment to the local field potential, reduced cross-frequency coupling, and fragmentation of brain states. Local application of S(+)-ketamine in (control) mice with intact NMDAR activity in PV neurons triggered network desynchronization and enhanced broadband gamma power. However, our investigations suggest that disparate mechanisms underlie increased broadband gamma power caused by genetic alteration of PV interneurons and ketamine-induced power increases in broadband gamma. Our study confirms that enhanced broadband gamma power can arise from asynchronous activities and demonstrates that long-term deficiency of PV inhibition can be a contributor. (AU)

FAPESP's process: 12/07107-2 - Episodic-like memory and oscillatory patterns in the hippocampus and medial prefrontal cortex of adult rats subjected to early-life seizures
Grantee:Cleiton Lopes Aguiar
Support type: Scholarships abroad - Research Internship - Doctorate