大脑视知觉调控的神经机制

摘要： 大脑的知觉加工并非单纯由外部刺激驱动，而是存在自上而下的知觉调控。尽管这一现象被大量实验研究证实，但其神经机制仍然是认知神经科学研究的重要问题。本研究系统介绍了知觉调控的神经基础、实现形式、研究范式，及其理论模型，分析指出了当前研究面临的主要问题，并对未来的研究进行了展望，以期促进该问题研究的进一步开展。
Abstract: Abstract：Human brain is a black-box dealing with a lot of stimulation in our everyday life. However, it is not a purely receiving machine in which the perception system is of plasticity and self-directed. Indeed, the visual areas in the brain are interconnected in a complex pattern of feedforward, lateral, and feedback pathways. The top-down system can send feed-back information to primary visual cortex which will affect what we perceived. For a long time, the magnitude of cortical influences on this processing in early sensory cortex is mostly underestimated. Human brain is not a purely receiving machine in which the perception system is of plasticity and self-directed. Indeed, the visual areas in the brain are interconnected in a complex pattern of feedforward, lateral, and feedback pathways. The top-down system can send feed-back information to primary visual cortex which will affect what we perceived. For a long time, the magnitude of cortical influences on this processing in early sensory cortex is mostly underestimated. In this review, we firstly conceptualized the processing of top-down modulation. Then we introduced the neural basic of top-down modulation in visual perception. Perception process has been showed to work in a spatially distributed cortical network including the subcortical structures and primary visual cortex. Early visual areas do more than encoding raw sensory signals, but they also participate in processing activities corresponding to a visual perception. Researches indicate that neural activation of top-down modulation is modulated by expertise, selective attention, mental imagery and even emotion. Methods which were usually used in past researches are also included in this review. Both of the figure-ground segregation paradigm and degraded paradigms are applied to realize the functional dissociation. And it is essential that feedforward and feedback modulation components are independently stimulated or inactivated. To provide more detailed insights, we highlighted the models interpretative of perception modulation function. (1)Attention modulation model posit that feedback to primary visual cortex modulates, tunes, or anticipates the bottom-up response to visual stimuli through selective attention. Top-down attention modulation is crucial for elucidating the mechanisms by which we can filter sensory information by paying attentions to the most