Neuroscience Training Program, University of Wisconsin-Madison, 1202 W. Johnson Street, Madison, WI 53706, USA.
Brain Connect. 2012;2(6):311-9. doi: 10.1089/brain.2012.0100. Epub 2012 Nov 14.
Schizophrenia is a severe mental illness with neurobiological bases that remain elusive. One hypothesis emphasizes disordered thalamic function. We previously used concurrent single pulse transcranial magnetic stimulation (spTMS) and functional magnetic resonance imaging (fMRI) to show that individuals with schizophrenia have a decreased spTMS-evoked response in the thalamus, and decreased effective connectivity between thalamus and insula and thalamus and superior frontal gyrus. To better understand the factors that may accompany or account for these findings, we investigated, in the same participants, resting state functional connectivity, white matter structural connectivity, and grey matter integrity. Patients with schizophrenia did not differ from healthy control subjects in resting state functional- or white matter structural connectivity, although they did show decreased measures of grey matter integrity in the insula. However, in this region, the spTMS-evoked response did not differ between groups. In a region of the thalamus that also had grey matter intensity abnormalities, although not at a level that survived correction for multiple comparisons, the spTMS-evoked response in patients was deficient. These results suggest that measures of structure and function are not necessarily complementary. Further, given its sensitivity for identifying deficits not evident with traditional imaging methods, these results highlight the utility of spTMS-fMRI, a method that directly and causally probes effective connectivity, as a tool for studying brain-based disorders.
精神分裂症是一种严重的精神疾病，其神经生物学基础仍难以捉摸。一种假设强调了丘脑功能障碍。我们之前使用同时进行的单次脉冲经颅磁刺激（spTMS）和功能磁共振成像（fMRI）表明，精神分裂症患者的丘脑 spTMS 诱发反应降低，丘脑与岛叶和丘脑与额上回之间的有效连接减少。为了更好地理解可能伴随或解释这些发现的因素，我们在相同的参与者中研究了静息状态功能连接、白质结构连接和灰质完整性。精神分裂症患者在静息状态功能连接或白质结构连接方面与健康对照组无差异，尽管他们在岛叶中确实显示出灰质完整性的测量值降低。然而，在该区域，两组之间的 spTMS 诱发反应没有差异。在丘脑的另一个区域也存在灰质强度异常，尽管在经过多次比较校正后未达到水平，但患者的 spTMS 诱发反应存在缺陷。这些结果表明，结构和功能的测量不一定是互补的。此外，鉴于其对识别传统成像方法无法显示的缺陷的敏感性，这些结果突出了 spTMS-fMRI 的实用性，该方法直接且因果地探测有效连接，是研究基于大脑的疾病的工具。
