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Blanco-Hinojo L, Pujol J, Macià D, Martínez-Vilavella G, Martín-Santos R, Pérez-Sola V, Deus J. Mapping the Synchronization Effect of Gamma-Aminobutyric Acid Inhibition on the Cerebral Cortex Using Magnetic Resonance Imaging. Brain Connect 2021; 11:393-403. [PMID: 33797949 DOI: 10.1089/brain.2020.0844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background: Functional magnetic resonance imaging (fMRI) of spontaneous brain activity permits the identification of functional networks on the basis of region synchrony. The functional coupling between the elements of a neural system increases during brain activation. However, neural synchronization may also be the effect of inhibitory gamma-aminobutyric acid (GABA) neurons in states of brain inhibition such as sleep or pharmacological sedation. We investigated the effects of an oral dose of alprazolam, a classical benzodiazepine known to enhance inhibitory neurotransmission, using recently developed measures of local functional connectivity. Methods: In a randomized, double-blind, placebo-controlled, crossover design, 32 non-treatment-seeking individuals with social anxiety underwent two identical resting-state fMRI sessions on separate days after receiving 0.75 mg of alprazolam and placebo. Functional connectivity maps of the cerebral cortex were generated by using multidistance functional connectivity measures defined within iso-distant local areas. Results: Relative to placebo, increased intracortical functional connectivity was observed in the alprazolam condition in visual, auditory, and sensorimotor cortices, and in areas of sensory integration such as the posterior insula and orbitofrontal cortex (OFC). Alprazolam significantly reduced subjective arousal compared with placebo, and the change was associated with variations in multidistance functional connectivity measures in the OFC. Discussion: In conclusion, we report evidence that alprazolam significantly modifies neural activity coupling at rest in the form of functional connectivity enhancement within the cerebral cortex. The effect of alprazolam was particularly evident in the cortical sensory system, which would further suggest a differentiated effect of GABA inhibition on sensory processing.
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Affiliation(s)
- Laura Blanco-Hinojo
- MRI Research Unit, Department of Radiology, Hospital del Mar, Barcelona, Spain.,Centro Investigación Biomédica en Red de Salud Mental, CIBERSAM, Barcelona, Spain
| | - Jesus Pujol
- MRI Research Unit, Department of Radiology, Hospital del Mar, Barcelona, Spain.,Centro Investigación Biomédica en Red de Salud Mental, CIBERSAM, Barcelona, Spain
| | - Dídac Macià
- MRI Research Unit, Department of Radiology, Hospital del Mar, Barcelona, Spain
| | | | - Rocío Martín-Santos
- Department of Psychiatry and Psychology, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Department of Medicine, Faculty of Medicine, and Institute of Neuroscience, University of Barcelona (UB), Barcelona, Spain
| | - Víctor Pérez-Sola
- Centro Investigación Biomédica en Red de Salud Mental, CIBERSAM, Barcelona, Spain.,Institute of Neuropsychiatry and Addictions, Hospital del Mar-IMIM, Barcelona, Spain.,Department of Psychiatry, Autonomous University of Barcelona, Barcelona, Spain
| | - Joan Deus
- MRI Research Unit, Department of Radiology, Hospital del Mar, Barcelona, Spain.,Department of Psychobiology and Methodology in Health Sciences, Autonomous University of Barcelona, Barcelona, Spain
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Ghosn NJ, Palmer JA, Borich MR, Ting LH, Payne AM. Cortical Beta Oscillatory Activity Evoked during Reactive Balance Recovery Scales with Perturbation Difficulty and Individual Balance Ability. Brain Sci 2020; 10:E860. [PMID: 33207570 PMCID: PMC7697848 DOI: 10.3390/brainsci10110860] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 11/06/2020] [Accepted: 11/12/2020] [Indexed: 11/16/2022] Open
Abstract
Cortical beta oscillations (13-30 Hz) reflect sensorimotor processing, but are not well understood in balance recovery. We hypothesized that sensorimotor cortical activity would increase under challenging balance conditions. We predicted greater beta power when balance was challenged, either by more difficult perturbations or by lower balance ability. In 19 young adults, we measured beta power over motor cortical areas (electroencephalography, Cz electrode) during three magnitudes of backward support -surface translations. Peak beta power was measured during early (50-150 ms), late (150-250 ms), and overall (0-400 ms) time bins, and wavelet-based analyses quantified the time course of evoked beta power. An ANOVA was used to compare peak beta power across perturbation magnitudes in each time bin. We further tested the association between perturbation-evoked beta power and individual balance ability measured in a challenging beam walking task. Beta power increased ~50 ms after perturbation, and to a greater extent in larger perturbations. Lower individual balance ability was associated with greater beta power in only the late (150-250 ms) time bin. These findings demonstrate greater sensorimotor cortical engagement under more challenging balance conditions, which may provide a biomarker for reduced automaticity in balance control that could be used in populations with neurological impairments.
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Affiliation(s)
- Nina J. Ghosn
- Georgia Institute of Technology, Atlanta, GA 30332, USA;
| | | | - Michael R. Borich
- Emory University, Atlanta, GA 30332, USA; (J.A.P.); (M.R.B.); (L.H.T.)
| | - Lena H. Ting
- Emory University, Atlanta, GA 30332, USA; (J.A.P.); (M.R.B.); (L.H.T.)
| | - Aiden M. Payne
- Emory University, Atlanta, GA 30332, USA; (J.A.P.); (M.R.B.); (L.H.T.)
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