Department of Clinical Sciences and Bio-imaging, University of Chieti, Chieti, Italy.
Neuroimage. 2010 Oct 15;53(1):181-8. doi: 10.1016/j.neuroimage.2010.06.023. Epub 2010 Jun 18.
It is well known that primary and non-primary areas of human somatosensory cortex are involved in the processing of adequate deviant/rare stimuli and omission of frequent stimuli. However, the relative weight and interaction of these variables is poorly known. This functional magnetic resonance imaging (fMRI) study tested the hypothesis that somatosensory stimulus processing and attention especially interact in non-primary somatosensory areas including secondary somatosensory cortex (SII) and insula. To test this hypothesis, responses of somatosensory cortex were mapped during four conditions of an oddball paradigm: DELIVERED COUNT and IGNORE (count or ignore deviant/rare electrical stimuli, respectively); OMITTED COUNT and IGNORE (count or ignore the rare omission of frequent electrical stimuli, respectively). The deviant/rare and frequent electrical stimuli were delivered to median and ulnar nerve, respectively. It was observed that contralateral (left) primary somatosensory responses were not markedly modulated by the mentioned deviant/rare events. Furthermore, contralateral SII and insula responded to all but not OMITTED IGNORE (purely attentive) condition, whereas ipsilateral (right) SII responded to all conditions. Finally, ipsilateral insula responded to the COUNT (attentive) conditions, regardless of the physical presence of the deviant/rare stimuli. The results suggest that in somatosensory modality, bilateral SII and left (contralateral) insula reflect complex integrative processes of stimulus elaboration and attention, whereas right (ipsilateral) insula mainly sub-serves active attention to deviance within a sequence of somatosensory stimuli.
众所周知，人类体感皮层的初级和非初级区域参与了适当的偏差/罕见刺激的处理和频繁刺激的忽略。然而，这些变量的相对权重和相互作用知之甚少。这项功能磁共振成像（fMRI）研究检验了这样一个假设，即体感刺激处理和注意力，特别是在非初级体感区域（包括次级体感皮层（SII）和脑岛）中相互作用。为了检验这一假设，在一种偶发范式的四种条件下绘制了体感皮层的反应图：DELIVERED COUNT 和 IGNORE（分别计数或忽略偏差/罕见的电刺激）；OMITTED COUNT 和 IGNORE（分别计数或忽略频繁电刺激的罕见遗漏）。偏差/罕见和频繁的电刺激分别施加到正中神经和尺神经。观察到，对侧（左）初级体感反应没有明显受到上述偏差/罕见事件的调制。此外，对侧 SII 和脑岛对所有条件都有反应，而不是对 OMITTED IGNORE（纯粹的注意）条件有反应，而同侧（右）SII 对所有条件都有反应。最后，同侧脑岛对 COUNT（注意）条件有反应，而不管偏差/罕见刺激的实际存在与否。研究结果表明，在体感模态中，双侧 SII 和左侧（对侧）脑岛反映了刺激细化和注意力的复杂综合过程，而右侧（同侧）脑岛主要负责在体感刺激序列中对偏差进行主动注意。
