Naeije G, Vaulet T, Wens V, Marty B, Goldman S, De Tiège X
Laboratoire de Cartographie fonctionnelle du Cerveau (LCFC), UNI - ULB Neuroscience Institute, Université libre de Bruxelles (ULB), Brussels, Belgium.
Laboratoire de Cartographie fonctionnelle du Cerveau (LCFC), CUB Hôpital Erasme, 808, route de Lennik, 1070, Brussels, Belgium.
Brain Topogr. 2018 Mar;31(2):242-256. doi: 10.1007/s10548-017-0591-x. Epub 2017 Sep 14.
The mismatch negativity (MMN) reflects the early detection of changes in sensory stimuli at the cortical level. The mechanisms underlying its genesis remain debated. This magnetoencephalography study investigates the spatio-temporal dynamics and the neural mechanisms of the magnetic somatosensory MMN. Somatosensory evoked magnetic fields elicited by tactile stimulation of the right fingertip (Single), tactile stimulation of the right middle phalanx and fingertip (Double) or omissions (Omitted) of tactile stimuli were studied in different paradigms: in oddballs where Double/Omitted followed a sequence of four Single, in sequences of two stimuli where Double occurred after one Single, and in random presentation of Double only. The predictability of Double occurrence in oddballs was also manipulated. Cortical sources of evoked responses were identified using equivalent current dipole modeling. Evoked responses elicited by Double were significantly different from those elicited by Single at the contralateral secondary somatosensory (cSII) cortex. Double elicited higher cSII cortex responses than Single when preceded by a sequence of four Single, compared to when they were preceded by one Single. Double elicited higher cSII cortex response when presented alone compared to when Double were preceded by one or a sequence of Single. Omitted elicited similar cSII cortex response than Single. Double in oddballs led to higher cSII cortex responses when less predictable. These data suggest that early tactile change detection involves mainly cSII cortex. The predictive coding framework probably accounts for the SII cortex response features observed in the different tactile paradigms.
失匹配负波（MMN）反映了皮质水平对感觉刺激变化的早期检测。其产生的机制仍存在争议。这项脑磁图研究调查了躯体感觉磁MMN的时空动态和神经机制。在不同范式下研究了由右指尖触觉刺激（单次）、右中指指节和指尖触觉刺激（双次）或触觉刺激缺失（遗漏）所诱发的躯体感觉诱发磁场：在异常刺激范式中，双次/遗漏刺激跟随四个单次刺激序列出现；在两个刺激的序列中，双次刺激在一个单次刺激之后出现；以及仅随机呈现双次刺激。还对异常刺激中双次刺激出现的可预测性进行了操控。使用等效电流偶极子模型确定诱发反应的皮质源。在对侧二级躯体感觉（cSII）皮质，双次刺激诱发的反应与单次刺激诱发的反应显著不同。与在一个单次刺激之后出现相比，当双次刺激在四个单次刺激序列之后出现时，双次刺激诱发的cSII皮质反应更高。与在一个单次刺激或单次刺激序列之后出现相比，双次刺激单独呈现时诱发的cSII皮质反应更高。遗漏刺激诱发的cSII皮质反应与单次刺激相似。在异常刺激中，当双次刺激的可预测性较低时，会导致更高的cSII皮质反应。这些数据表明，早期触觉变化检测主要涉及cSII皮质。预测编码框架可能解释了在不同触觉范式中观察到的SII皮质反应特征。
