Weber Sarah, Hjelmervik Helene, Craven Alexander R, Johnsen Erik, Kroken Rune A, Løberg Else-Marie, Ersland Lars, Kompus Kristiina, Hugdahl Kenneth
Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway.
Division of Psychiatry and NORMENT Centre of Excellence, Haukeland University Hospital, Bergen, Norway.
Front Psychiatry. 2021 Feb 17;12:643564. doi: 10.3389/fpsyt.2021.643564. eCollection 2021.
Auditory verbal hallucinations (AVH) have been linked to aberrant interhemispheric connectivity between the left and the right superior temporal gyrus (STG), labeled the interhemispheric miscommunication theory. The present study investigated if interhemispheric miscommunication is modulated at the neurochemical level by glutamate (Glu) and gamma-aminobutyric acid (GABA) concentrations in temporal and prefrontal lobe areas, as proposed by the theory. We combined resting-state fMRI connectivity with MR spectroscopy (MRS) in a sample of 81 psychosis patients, comparing patients with high hallucination severity (high-AVH) and low hallucination severity (low-AVH) groups. Glu and GABA concentrations were acquired from the left STG and the anterior cingulate cortex (ACC), an area of cognitive control that has been proposed to modulate STG functioning in AVH. Functional connectivity showed significant interaction effects between AVH Group and ACC-recorded Glu and GABA metabolites. Follow-up tests showed that there was a significant positive association for Glu concentration and interhemispheric STG connectivity in the high-AVH group, while there was a significant negative association for GABA concentration and interhemispheric STG connectivity in the low-AVH group. The results show neurochemical modulation of STG interhemispheric connectivity, as predicted by the interhemispheric miscommunication hypothesis. Furthermore, the findings are in line with an excitatory/inhibitory imbalance model for AVH. By combining different neuroimaging modalities, the current results provide a more comprehensive insight into the neural correlates of AVH.
听觉言语幻觉（AVH）与左右颞上回（STG）之间异常的半球间连接有关，这一理论被称为半球间沟通障碍理论。本研究探讨了如该理论所提出的，半球间沟通障碍是否在神经化学水平上受颞叶和前额叶区域谷氨酸（Glu）和γ-氨基丁酸（GABA）浓度的调节。我们在81名精神病患者样本中，将静息态功能磁共振成像（fMRI）连接性与磁共振波谱（MRS）相结合，比较了幻觉严重程度高（高AVH）和幻觉严重程度低（低AVH）的两组患者。从左侧STG和前扣带回皮质（ACC）获取Glu和GABA浓度，ACC是一个认知控制区域，被认为可调节AVH中STG的功能。功能连接性显示，AVH组与ACC记录的Glu和GABA代谢物之间存在显著的交互作用。后续测试表明，高AVH组中Glu浓度与半球间STG连接性呈显著正相关，而低AVH组中GABA浓度与半球间STG连接性呈显著负相关。结果表明，如半球间沟通障碍假说所预测的，STG半球间连接存在神经化学调节。此外，这些发现与AVH的兴奋/抑制失衡模型一致。通过结合不同的神经成像方式，目前的结果为AVH的神经相关性提供了更全面的见解。
