Murray Micah M, Molholm Sophie, Michel Christoph M, Heslenfeld Dirk J, Ritter Walter, Javitt Daniel C, Schroeder Charles E, Foxe John J
The Cognitive Neurophysiology Lab, Nathan S. Kline Institute for Psychiatric Research, Program in Cognitive Neuroscience and Schizophrenia, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.
Cereb Cortex. 2005 Jul;15(7):963-74. doi: 10.1093/cercor/bhh197. Epub 2004 Nov 10.
Multisensory interactions are observed in species from single-cell organisms to humans. Important early work was primarily carried out in the cat superior colliculus and a set of critical parameters for their occurrence were defined. Primary among these were temporal synchrony and spatial alignment of bisensory inputs. Here, we assessed whether spatial alignment was also a critical parameter for the temporally earliest multisensory interactions that are observed in lower-level sensory cortices of the human. While multisensory interactions in humans have been shown behaviorally for spatially disparate stimuli (e.g. the ventriloquist effect), it is not clear if such effects are due to early sensory level integration or later perceptual level processing. In the present study, we used psychophysical and electrophysiological indices to show that auditory-somatosensory interactions in humans occur via the same early sensory mechanism both when stimuli are in and out of spatial register. Subjects more rapidly detected multisensory than unisensory events. At just 50 ms post-stimulus, neural responses to the multisensory 'whole' were greater than the summed responses from the constituent unisensory 'parts'. For all spatial configurations, this effect followed from a modulation of the strength of brain responses, rather than the activation of regions specifically responsive to multisensory pairs. Using the local auto-regressive average source estimation, we localized the initial auditory-somatosensory interactions to auditory association areas contralateral to the side of somatosensory stimulation. Thus, multisensory interactions can occur across wide peripersonal spatial separations remarkably early in sensory processing and in cortical regions traditionally considered unisensory.
从单细胞生物到人类的各种物种中都观察到了多感官相互作用。早期的重要研究主要在猫的上丘进行，并定义了其发生的一组关键参数。其中最主要的是双感官输入的时间同步和空间对齐。在这里，我们评估了空间对齐是否也是人类低级感觉皮层中观察到的时间上最早的多感官相互作用的关键参数。虽然人类的多感官相互作用在行为上已被证明适用于空间上不同的刺激（例如腹语效应），但尚不清楚这种效应是由于早期的感觉水平整合还是后期的知觉水平处理。在本研究中，我们使用心理物理学和电生理指标表明，无论刺激是否在空间对齐，人类的听觉 - 体感相互作用都通过相同的早期感觉机制发生。与单感官事件相比，受试者能更快地检测到多感官事件。在刺激后仅50毫秒，对多感官“整体”的神经反应就大于来自组成单感官“部分”的反应总和。对于所有空间配置，这种效应源于大脑反应强度的调制，而不是对多感官对特异性反应的区域的激活。使用局部自回归平均源估计，我们将最初的听觉 - 体感相互作用定位到体感刺激侧对侧的听觉联合区域。因此，多感官相互作用可以在感觉处理的早期以及传统上被认为是单感官的皮层区域中，跨越广泛的个人周边空间间隔显著发生。
