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Silverstein BH, Kolbman N, Nelson A, Liu T, Guzzo P, Gilligan J, Lee U, Mashour GA, Vanini G, Pal D. Psilocybin induces dose-dependent changes in functional network organization in rat cortex. bioRxiv 2024:2024.02.09.579718. [PMID: 38405722 PMCID: PMC10888735 DOI: 10.1101/2024.02.09.579718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Psilocybin produces an altered state of consciousness in humans and is associated with complex spatiotemporal changes in brain networks. Given the emphasis on rodent models for mechanistic studies, there is a need for characterization of the effect of psilocybin on brain-wide network dynamics. Previous rodent studies of psychedelics, using electroencephalogram, have primarily been done with sparse electrode arrays that offered limited spatial resolution precluding network level analysis, and have been restricted to lower gamma frequencies. Therefore, in the study, we used electroencephalographic recordings from 27 sites (electrodes) across rat cortex (n=6 male, 6 female) to characterize the effect of psilocybin (0.1 mg/kg, 1 mg/kg, and 10 mg/kg delivered over an hour) on network organization as inferred through changes in node degree (index of network density) and connection strength (weighted phase-lag index). The removal of aperiodic component from the electroencephalogram localized the primary oscillatory changes to theta (4-10 Hz), medium gamma (70-110 Hz), and high gamma (110-150 Hz) bands, which were used for the network analysis. Additionally, we determined the concurrent changes in theta-gamma phase-amplitude coupling. We report that psilocybin, in a dose-dependent manner, 1) disrupted theta-gamma coupling [p<0.05], 2) increased frontal high gamma connectivity [p<0.05] and posterior theta connectivity [p≤0.049], and 3) increased frontal high gamma [p<0.05] and posterior theta [p≤0.046] network density. The medium gamma frontoparietal connectivity showed a nonlinear relationship with psilocybin dose. Our results suggest that high-frequency network organization, decoupled from local theta-phase, may be an important signature of psilocybin-induced non-ordinary state of consciousness.
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Affiliation(s)
- Brian H Silverstein
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Nicholas Kolbman
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Amanda Nelson
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Tiecheng Liu
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Peter Guzzo
- Tryp Therapeutics, Kelowna, British Columbia, V1Y 7T2, Canada
| | - Jim Gilligan
- Tryp Therapeutics, Kelowna, British Columbia, V1Y 7T2, Canada
| | - UnCheol Lee
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - George A Mashour
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Giancarlo Vanini
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Dinesh Pal
- Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan 48109, USA
- Center for Consciousness Science, University of Michigan, Ann Arbor, Michigan 48109, USA
- Michigan Psychedelic Center, University of Michigan, Ann Arbor, Michigan 48109, USA
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109, USA
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Ross B, Tremblay KL, Alain C. Simultaneous EEG and MEG recordings reveal vocal pitch elicited cortical gamma oscillations in young and older adults. Neuroimage 2019; 204:116253. [PMID: 31600592 DOI: 10.1016/j.neuroimage.2019.116253] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/13/2019] [Accepted: 10/06/2019] [Indexed: 10/25/2022] Open
Abstract
The frequency-following response with origin in the auditory brainstem represents the pitch contour of voice and can be recorded with electrodes from the scalp. MEG studies also revealed a cortical contribution to the high gamma oscillations at the fundamental frequency (f0) of a vowel stimulus. Therefore, studying the cortical component of the frequency-following response could provide insights into how pitch information is encoded at the cortical level. Comparing how aging affects the different responses may help to uncover the neural mechanisms underlying speech understanding deficits in older age. We simultaneously recorded EEG and MEG responses to the syllable /ba/. MEG beamformer analysis localized sources in bilateral auditory cortices and the midbrain. Time-frequency analysis showed a faithful representation of the pitch contour between 106 Hz and 138 Hz in the cortical activity. A cross-correlation revealed a latency of 20 ms. Furthermore, stimulus onsets elicited cortical 40-Hz responses. Both the 40-Hz and the f0 response amplitudes increased in older age and were larger in the right hemisphere. The effects of aging and laterality of the f0 response were evident in the MEG only, suggesting that both effects were characteristics of the cortical response. After comparing f0 and N1 responses in EEG and MEG, we estimated that approximately one-third of the scalp-recorded f0 response could be cortical in origin. We attributed the significance of the cortical f0 response to the precise timing of cortical neurons that serve as a time-sensitive code for pitch.
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Affiliation(s)
- Bernhard Ross
- Rotman Research Institute, Baycrest Centre, Toronto, Ontario, Canada; Department for Medical Biophysics, University of Toronto, Ontario, Canada.
| | - Kelly L Tremblay
- Department of Speech and Hearing Sciences, University of Washington, Seattle, WA, USA
| | - Claude Alain
- Rotman Research Institute, Baycrest Centre, Toronto, Ontario, Canada; Department of Psychology, University of Toronto, Ontario, Canada
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