Neurochemistry and functional connectivity in the brain of people with Charles Bonnet syndrome.
Background: Charles Bonnet syndrome (CBS) is a condition in which people with vision loss experience complex visual hallucinations. These complex visual hallucinations may be caused by increased excitability in the visual cortex that are present in some people with vision loss but not others. Object...
| Published in: | Therapeutic Advances in Ophthalmology pp. 1 - 19 |
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| Main Authors: | , , , , , , , , |
| Format: | diagnostic images pictorial research tables/charts Journal Article |
| Published: |
Sage Publications Inc.
10/15/2024
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| Online Access: | View this record in EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=ccm&AN=180332318&site=ehost-live header: @attributes: shortDbName: ccm uiTerm: 180332318 longDbName: CINAHL Complete uiTag: AN controlInfo: bkinfo: dissinfo: jinfo: jid: 25158414 LAW0 jtl: Therapeutic Advances in Ophthalmology issn: 25158414 maglogo: Y pubinfo: dt: 10/15/2024 pid: 344 pub: Sage Publications Inc. place: Thousand Oaks, California artinfo: ui: 180332318 180332318 180332318 10.1177/25158414241280201 180332318 ppf: 1 ppct: 18 formats: fmt: – @attributes: type: T – @attributes: type: P tig: atl: Neurochemistry and functional connectivity in the brain of people with Charles Bonnet syndrome. aug: au: Bridge, Holly Wyllie, Abigail Kay, Aaron Rand, Bailey Starling, Lucy Millington-Truby, Rebecca S. Clarke, William T. Jolly, Jasleen K. Ip, I. Betina affil: Conceptualization, Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, Oxford, UK sug: subj: Charles Bonnet Syndrome Physiopathology Functional Connectivity Biochemistry Evaluation Brain Pathology Vision Disorders Physiopathology Evoked Potentials, Visual Evaluation GABA Antagonists and Inhibitors Hallucinations Physiopathology Visual Perception Evaluation Brain Mapping Methods Human Prospective Studies Cross Sectional Studies Nonexperimental Studies Case Control Studies Magnetic Resonance Spectroscopy Visual Acuity Cognition Funding Source Occipital Lobe Radiography Magnetic Resonance Imaging Methods ab: Background: Charles Bonnet syndrome (CBS) is a condition in which people with vision loss experience complex visual hallucinations. These complex visual hallucinations may be caused by increased excitability in the visual cortex that are present in some people with vision loss but not others. Objectives: We aimed to evaluate the association between γ-aminobutyric acid (GABA) in the visual cortex and CBS. We also tested the relationship among visually evoked responses, functional connectivity, and CBS. Design: This is a prospective, case-controlled, cross-sectional observational study. Methods: We applied 3-Tesla magnetic resonance spectroscopy, as well as task-based and resting state (RS) connectivity functional magnetic resonance imaging in six participants with CBS and six controls without CBS. GABA+ was measured in the early visual cortex (EVC) and in the lateral occipital cortex (LOC). Participants also completed visual acuity and cognitive tests, and the North-East Visual Hallucinations Interview. Results: The two groups were well-matched for age, gender, visual acuity and cognitive scores. There was no difference in GABA+ levels between groups in the visual cortex. Most participants showed the expected blood oxygenation level dependent (BOLD) activation to images of objects and the phase-scrambled control. Using a fixed effects analysis, we found that BOLD activation was greater in participants with CBS compared to controls. Analysis of RS connectivity with LOC and EVC showed little difference between groups. A fixed effects analysis showed a correlation between the extent of functional connectivity with LOC and hallucination strength. Conclusion: Overall, our results provide no strong evidence for an association between GABAergic inhibition in the visual cortex and CBS. We only found subtle differences in visual function and connectivity between groups. These findings suggest that the neurochemistry and visual connectivity for people with Charles Bonnet hallucinations are comparable to a sight loss population. Differences between groups may emerge when investigating subtle and transient changes that occur at the time of visual hallucinations. Plain language summary: Brain imaging in Charles Bonnet syndrome In Charles Bonnet Syndrome (CBS), people with sight loss start to see hallucinations that they know are not real but can be disturbing. In this study we used MRI scanning to measure how the chemistry in the visual brain differs in people with CBS and those who have sight loss but no hallucinations. Surprisingly we did not find any differences in chemistry between these groups, suggesting that their brains do not differ greatly. Any differences in how their visual brain works may be too small to measure, or only present when people hallucinate. pubtype: Academic Journal doctype: diagnostic images pictorial research tables/charts Journal Article ougenre: Article language: English refInfo: holdings: @attributes: islocal: N |
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