人类感觉通道主导效应与利手效应之间交互作用的行为和神经机制

多感觉信息加工中，某个感觉通道会更频繁地取得通达运动系统的优先权，并最终主导意识和行为，既感觉主导效应。利手效应在人类出生前已开始发展，是人类运动系统一种与生俱来的特质。那么，作为人类运动系统先天特质的利手效应是否会被感觉主导效应消除甚至反转？我们实验室近期的创新性实验结果表明，大多数人类可被划分为两类：一类人的利手优势只体现在对视觉刺激的反应上，而对听觉刺激的反应会消除甚至反转利手效应；相反，另一类人的利手优势只体现在听觉反应上，而视觉反应会消除甚至反转利手优势。我们将使用心理物理理法、功能磁共振、脑磁图和行为节律等方法，进一步回答主导/非主导感觉表征与利手/非利手感觉运动表征交互作用过程中的两个关键问题：（1）这两类人群的基本感知觉系统、运动系统和额顶系统相互联结的动态脑网络特异模式；（2）这两类人群，从早期感知觉表征到晚期感觉运动表征转化过程中，在时间进程和神经振荡特性上的动态差异。

When task-relevant multisensory information reaches the human brain, perceptual representations in the respective sensory system need to be transformed to the corresponding sensorimotor representations, and compete for preferential access to the motor system. Depending on the current task demands, one modality more frequently gains preferential processing, and eventually dominates consciousness and behavior. This phenomenon is termed as the sensory dominance effect. Hand dominance, as an innate nature of the human motor system, evolves even before birth, stabilizes during early childhood, and has been attributed to genetic factors. Independent of cultural background, 90% of humans prefer the right hand for skilled manipulation, i.e. right-handed. Although the neural pathway via which the visual and auditory perceptual information is transformed to the corresponding sensorimotor representations has been well studied, separately in their respective field, it remains unknown how the sensory dominance effect between different sensory modalities interacts with the hand dominance effect. In particular, whether hand dominance, the innate nature of the human motor system, can be eliminated or even reversed by sensory dominance. One major novel finding from our lab showed that the majority of the human population could be categorized into two types. In one type of people, the dominant hand effect manifested in responding to the visual stimuli, but was eliminated or even reversed in responding to the auditory stimuli. By contrast in the other type of people, the dominant hand effect occurred only for the auditory responses, but was eliminated or even reversed upon the visual responses. By using psychophysics, fMRI, MEG, and behavioural oscillation techniques in the present project, we aim to answer the following two critical questions: (1) by using fMRI and the corresponding connectivity analysis, we aim to investigate the specific network dynamics underlying how the auditory vs. visual sensory representations in the different sensory systems interact with the sensorimotor representations of the dominant vs. non-dominant hand in the motor system, in the two types of group; (2) by MEG and the corresponding numerous analysis in the time and frequency domains, we aim to further test the temporal progress and neural oscillation characteristics from the earlier perceptual representations to the later sensorimotor representations during the interaction between sensory dominance and hand dominance, in the two types of group.