Holly Bridge, Abigail Wyllie, Aaron Kay, Bailey Rand, Lucy Starling, Rebecca S Millington-Truby, William T Clarke, Jasleen K Jolly, I Betina Ip
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We also tested the relationship among visually evoked responses, functional connectivity, and CBS.</p><p><strong>Design: </strong>This is a prospective, case-controlled, cross-sectional observational study.</p><p><strong>Methods: </strong>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.</p><p><strong>Results: </strong>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.</p><p><strong>Conclusion: </strong>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.</p>","PeriodicalId":23054,"journal":{"name":"Therapeutic Advances in Ophthalmology","volume":null,"pages":null},"PeriodicalIF":2.3000,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11481065/pdf/","citationCount":"0","resultStr":"{\"title\":\"Neurochemistry and functional connectivity in the brain of people with Charles Bonnet syndrome.\",\"authors\":\"Holly Bridge, Abigail Wyllie, Aaron Kay, Bailey Rand, Lucy Starling, Rebecca S Millington-Truby, William T Clarke, Jasleen K Jolly, I Betina Ip\",\"doi\":\"10.1177/25158414241280201\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><strong>Background: </strong>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.</p><p><strong>Objectives: </strong>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.</p><p><strong>Design: </strong>This is a prospective, case-controlled, cross-sectional observational study.</p><p><strong>Methods: </strong>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). 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引用次数: 0
摘要
背景:查尔斯-博内特综合征(CBS)是一种视力丧失患者会出现复杂视幻觉的病症。这些复杂的视觉幻觉可能是由视觉皮层兴奋性增高引起的,有些视力丧失患者会出现这种幻觉,而另一些患者则不会:我们旨在评估视觉皮层中的γ-氨基丁酸(GABA)与CBS之间的关系。我们还测试了视觉诱发反应、功能连接和 CBS 之间的关系:这是一项前瞻性、病例对照、横断面观察研究:方法:我们对六名患有 CBS 的参与者和六名未患 CBS 的对照者进行了 3-Tesla 磁共振波谱分析,以及基于任务和静息状态 (RS) 连接的功能磁共振成像。对早期视觉皮层(EVC)和外侧枕叶皮层(LOC)的 GABA+ 进行了测量。参与者还完成了视力和认知测试以及东北视幻觉访谈:结果:两组患者在年龄、性别、视力和认知评分方面完全匹配。视觉皮层中的 GABA+ 水平在两组之间没有差异。大多数参与者对物体图像和相位乱码对照组表现出预期的血氧水平依赖性(BOLD)激活。通过固定效应分析,我们发现与对照组相比,CBS 患者的 BOLD 激活程度更高。对 RS 与 LOC 和 EVC 连接性的分析表明,组间差异很小。固定效应分析表明,与 LOC 的功能连接程度与幻觉强度之间存在相关性:总之,我们的研究结果没有提供强有力的证据证明视觉皮层中的 GABA 能抑制与 CBS 之间存在关联。我们只发现了不同组之间在视觉功能和连接性方面的细微差别。这些研究结果表明,查尔斯-博奈幻觉患者的神经化学和视觉连通性与失明人群相似。在研究出现视觉幻觉时发生的微妙和短暂变化时,可能会发现不同群体之间存在差异。
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.
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.