Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada.
Magn Reson Med. 2012 Sep;68(3):923-31. doi: 10.1002/mrm.23292. Epub 2011 Dec 9.
Previous functional MRI studies of normal sensory function in the human spinal cord, including right-to-left symmetry of activity, have been influenced by order effects between repeated studies. In this study, we apply thermal sensory stimulation to four dermatomes within each functional MRI time-series acquisition. Each of the four dermatomes receives a unique stimulation paradigm, such that the four paradigms form a linearly independent set, enabling detection of each individual stimulus response. Functional MRI data are shown spanning the cervical spinal cord and brainstem in 10 healthy volunteers. Results of general linear model analysis demonstrate consistent patterns of activity within the spinal cord segments corresponding to each dermatome, and a high degree of symmetry between right-side and left-side stimulation. Connectivity analyses also demonstrate consistent areas of activity and connectivity between spinal cord and brainstem regions corresponding to known anatomy. However, right-side and left-side responses are not at precisely the same rostral-caudal positions, but are offset by several millimeters, with left-side responses consistently more caudal than right-side responses. The results confirm that distinct responses to multiple interleaved sensory stimuli can be distinguished, enabling studies of sensory responses within the spinal cord without the confounding effects of comparing sequential studies.
先前的人类脊髓正常感觉功能的功能性磁共振成像研究，包括活动的左右对称性，受到重复研究之间的顺序效应的影响。在这项研究中，我们在每个功能性磁共振成像时间序列采集的四个皮区内应用热感觉刺激。四个皮区中的每一个都接受独特的刺激范式，使得四个范式形成线性独立的集合，从而能够检测到每个单独的刺激反应。功能性磁共振成像数据显示在 10 名健康志愿者的颈脊髓和脑干范围内。一般线性模型分析的结果表明，与每个皮区相对应的脊髓节段内的活动具有一致的模式，并且右侧和左侧刺激之间具有高度的对称性。连接性分析还表明，与已知解剖结构相对应的脊髓和脑干区域之间存在一致的活动和连接性。然而，右侧和左侧的反应并不完全处于相同的颅尾位置，而是相差几毫米，左侧反应始终比右侧反应更靠尾侧。结果证实，可以区分对多个交错感觉刺激的不同反应，从而能够在没有比较顺序研究的混杂影响的情况下研究脊髓内的感觉反应。
