Jacob Michael S, Roach Brian J, Mathalon Daniel H, Ford Judith M
San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA, 94121, United States.
University of California, San Francisco, 505 Parnassus Ave, San Francisco, CA, 94143, United States.
medRxiv. 2025 Jan 15:2025.01.14.25320216. doi: 10.1101/2025.01.14.25320216.
Neuroimaging methods rely on models of neurovascular coupling that assume hemodynamic responses evolve seconds after changes in neural activity. However, emerging evidence reveals noncanonical BOLD (blood oxygen level dependent) responses that are delayed under stress and aberrant in neuropsychiatric conditions. To investigate BOLD coupling to resting-state fluctuations in neural activity, we simultaneously recorded EEG and fMRI in people with schizophrenia and psychiatrically unaffected participants. We focus on alpha band power to examine voxelwise, time-lagged BOLD correlations. Principally, we find diversity in the temporal profile of alpha-BOLD coupling within regions of the default mode network (DMN). This includes early coupling (0-2 seconds BOLD lag) for more posterior regions, thalamus and brainstem. Anterior regions of the DMN show coupling at canonical lags (4-6 seconds), with greater lag scores associated with self-reported measures of stress and greater lag scores in participants with schizophrenia. Overall, noncanonical alpha-BOLD coupling is widespread across the DMN and other non-cortical regions, and is delayed in people with schizophrenia. These findings are consistent with a "hemo-neural" hypothesis, that blood flow and/or metabolism can regulate ongoing neural activity, and further, that the hemo-neural lag may be associated with subjective arousal or stress. Our work highlights the need for more studies of neurovascular coupling in psychiatric conditions.
神经成像方法依赖于神经血管耦合模型，该模型假定血液动力学反应在神经活动变化数秒后才会出现。然而，新出现的证据揭示了非典型的血氧水平依赖（BOLD）反应，这种反应在压力下会延迟，在神经精神疾病中也会异常。为了研究BOLD与神经活动静息态波动的耦合关系，我们同时记录了精神分裂症患者和精神状态正常的参与者的脑电图（EEG）和功能磁共振成像（fMRI）。我们聚焦于阿尔法波段功率，以检查体素层面的、有时间延迟的BOLD相关性。主要地，我们发现在默认模式网络（DMN）区域内，阿尔法-BOLD耦合的时间特征存在多样性。这包括更靠后的区域、丘脑和脑干的早期耦合（BOLD延迟0 - 2秒）。DMN的前部区域在典型延迟（4 - 6秒）时出现耦合，更高的延迟分数与自我报告的压力测量值相关，且在精神分裂症患者中延迟分数更高。总体而言，非典型的阿尔法-BOLD耦合在DMN和其他非皮质区域广泛存在，并且在精神分裂症患者中延迟。这些发现与“血液-神经”假说一致，即血流和/或代谢可以调节正在进行的神经活动，而且，血液-神经延迟可能与主观唤醒或压力有关。我们的工作强调了在精神疾病中对神经血管耦合进行更多研究的必要性。
