Psychiatry Department, School of Medicine, University of Valladolid, Av. Ramón y Cajal, 7, 47005, Valladolid, Spain.
Biomedical Research Institute of Salamanca (IBSAL), Salamanca, Spain.
Eur Arch Psychiatry Clin Neurosci. 2019 Jun;269(4):419-428. doi: 10.1007/s00406-018-0877-3. Epub 2018 Feb 2.
The study of cerebral underpinnings of schizophrenia may benefit from the high temporal resolution of electromagnetic techniques, but its spatial resolution is low. However, source imaging approaches such as low-resolution brain electromagnetic tomography (LORETA) allow for an acceptable compromise between spatial and temporal resolutions.
We combined LORETA with 32 channels and 3-Tesla diffusion magnetic resonance (Dmr) to study cerebral dysfunction in 38 schizophrenia patients (17 first episodes, FE), compared to 53 healthy controls. The EEG was acquired with subjects performing an odd-ball task. Analyses included an adaptive window of interest to take into account the interindividual variability of P300 latency. We compared source activation patters to distractor (P3a) and target (P3b) tones within- and between-groups.
Patients showed a reduced activation in anterior cingulate and lateral and medial prefrontal cortices, as well as inferior/orbital frontal regions. This was also found in the FE patients alone. The activation was directly related to IQ in the patients and controls and to working memory performance in controls. Symptoms were unrelated to source activation. Fractional anisotropy in the tracts connecting lateral prefrontal and anterior cingulate regions predicted source activation in these regions in the patients.
These results replicate the source activation deficit found in a previous study with smaller sample size and a lower number of sensors and suggest an association between structural connectivity deficits and functional alterations.
精神分裂症的大脑基础研究可以受益于电磁技术的高时间分辨率，但空间分辨率较低。然而，源成像方法，如低分辨率脑电磁断层扫描（LORETA），可以在空间和时间分辨率之间取得可接受的折衷。
我们将 LORETA 与 32 个通道和 3 特斯拉弥散磁共振（Dmr）相结合，研究了 38 名精神分裂症患者（17 名首发，FE）与 53 名健康对照组的大脑功能障碍。EEG 是在受试者执行奇数球任务时获得的。分析包括自适应感兴趣窗口，以考虑 P300 潜伏期的个体间变异性。我们比较了源激活模式与分心（P3a）和目标（P3b）音在组内和组间的差异。
患者在前扣带回和外侧及内侧前额叶皮层以及下/眶额区域表现出激活减少。在 FE 患者中也发现了这种情况。激活与患者和对照组的智商以及对照组的工作记忆表现直接相关。症状与源激活无关。连接外侧前额叶和前扣带回区域的束的各向异性分数预测了患者在这些区域的源激活。
这些结果复制了先前一项研究中发现的源激活缺陷，该研究样本量较小，传感器数量较少，并提示结构连接缺陷与功能改变之间存在关联。
