Selective blockade of rat brain T-type calcium channels provides insights on neurophysiological basis of arousal dependent resting state functional magnetic resonance imaging signals

• Type of Material: Article
• Authors: Vahid Khalilzad Sharghi, Emory University; Eric A Maltbie, Emory University-Georgia Tech; Wenju Pan, Emory University; Shella Keilholz, Emory University; Kaundinya Gopinath, Emory University
• Language: English
• Date: 2022-08-08
• Publisher: FRONTIERS MEDIA SA
• Publication Version: Final Published Version
• Copyright Statement: © 2022 Khalilzad Sharghi, Maltbie, Pan, Keilholz and Gopinath.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.3389/fnins.2022.909999
• Title of Journal or Parent Work: FRONTIERS IN NEUROSCIENCE
• Volume: 16
• Start Page: 909999
• End Page: 909999
• Grant/Funding Information: Additional support was provided by Departments of Radiology and Imaging Sciences, and Biomedical Engineering, Emory University.; Research reported in this publication was supported by National Institute of Neurological Disorders and Stroke of the National Institutes of Health under award number 1R21NS122013-01A1.
• Keywords: cortical slow wave activity; T-type calcium channel blocker; Life Sciences & Biomedicine; BOLD FLUCTUATIONS; QUASI-PERIODIC PATTERNS; arousal; animal studies; resting state fMRI; NEOCORTICAL NEURONS; quasiperiodic patterns; NEURAL ACTIVITY; CA2+ CHANNELS; vigilance; GENERAL-ANESTHESIA; Neurosciences & Neurology; SLOW-WAVE SLEEP; INTERHEMISPHERIC COORDINATION; Science & Technology; SPATIOTEMPORAL DYNAMICS; THALAMIC NEURONS; Neurosciences
• Research Categories: Engineering, Biomedical

Abstract

A number of studies point to slow (0.1–2 Hz) brain rhythms as the basis for the resting-state functional magnetic resonance imaging (rsfMRI) signal. Slow waves exist in the absence of stimulation, propagate across the cortex, and are strongly modulated by vigilance similar to large portions of the rsfMRI signal. However, it is not clear if slow rhythms serve as the basis of all neural activity reflected in rsfMRI signals, or just the vigilance-dependent components. The rsfMRI data exhibit quasi-periodic patterns (QPPs) that appear to increase in strength with decreasing vigilance and propagate across the brain similar to slow rhythms. These QPPs can complicate the estimation of functional connectivity (FC) via rsfMRI, either by existing as unmodeled signal or by inducing additional wide-spread correlation between voxel-time courses of functionally connected brain regions. In this study, we examined the relationship between cortical slow rhythms and the rsfMRI signal, using a well-established pharmacological model of slow wave suppression. Suppression of cortical slow rhythms led to significant reduction in the amplitude of QPPs but increased rsfMRI measures of intrinsic FC in rats. The results suggest that cortical slow rhythms serve as the basis of only the vigilance-dependent components (e.g., QPPs) of rsfMRI signals. Further attenuation of these non-specific signals enhances delineation of brain functional networks.