Reed Catherine L, Shoham Shy, Halgren Eric
Department of Psychology, University of Denver, Denver, Colorado 80208, USA.
Hum Brain Mapp. 2004 Apr;21(4):236-46. doi: 10.1002/hbm.10162.
A functional magnetic resonance imaging (fMRI) study was conducted during which seven subjects carried out naturalistic tactile object recognition (TOR) of real objects. Activation maps, conjunctions across subjects, were compared between tasks involving TOR of common real objects, palpation of "nonsense" objects, and rest. The tactile tasks involved similar motor and sensory stimulation, allowing higher tactile recognition processes to be isolated. Compared to nonsense object palpation, the most prominent activation evoked by TOR was in secondary somatosensory areas in the parietal operculum (SII) and insula, confirming a modality-specific path for TOR. Prominent activation was also present in medial and lateral secondary motor cortices, but not in primary motor areas, supporting the high level of sensory and motor integration characteristic of object recognition in the tactile modality. Activation in a lateral occipitotemporal area associated previously with visual object recognition may support cross-modal collateral activation. Finally, activation in medial temporal and prefrontal areas may reflect a common final pathway of modality-independent object recognition. This study suggests that TOR involves a complex network including parietal and insular somatosensory association cortices, as well as occipitotemporal visual areas, prefrontal, and medial temporal supramodal areas, and medial and lateral secondary motor cortices. It confirms the involvement of somatosensory association areas in the recognition component of TOR, and the existence of a ventrolateral somatosensory pathway for TOR in intact subjects. It challenges the results of previous studies that emphasize the role of visual cortex rather than somatosensory association cortices in higher-level somatosensory cognition.
进行了一项功能磁共振成像（fMRI）研究，期间七名受试者对真实物体进行了自然主义的触觉物体识别（TOR）。比较了涉及常见真实物体的TOR任务、“无意义”物体的触诊任务和休息状态下受试者之间的激活图及联合激活情况。触觉任务涉及相似的运动和感觉刺激，从而能够分离出更高层次的触觉识别过程。与无意义物体触诊相比，TOR引发的最显著激活出现在顶叶岛盖（SII）和脑岛的次级体感区，证实了TOR存在特定模态路径。内侧和外侧次级运动皮层也有显著激活，但初级运动区没有，这支持了触觉模态中物体识别所具有的高度感觉和运动整合特征。先前与视觉物体识别相关的外侧枕颞区的激活可能支持跨模态并行激活。最后，内侧颞叶和前额叶区域的激活可能反映了与模态无关的物体识别的共同最终路径。这项研究表明，TOR涉及一个复杂的网络，包括顶叶和岛叶体感联合皮层，以及枕颞视觉区、前额叶和内侧颞叶超模态区，还有内侧和外侧次级运动皮层。它证实了体感联合区参与了TOR的识别成分，以及在完整受试者中存在一条用于TOR的腹外侧体感通路。它对先前强调视觉皮层而非体感联合皮层在高级体感认知中作用的研究结果提出了挑战。
