Development of multisensory processing in cortico-subcortical networks

虽然感觉处理是神经科学中一个恒定的研究课题，但它的研究主要是通过一次考虑单一的感觉模态来实现的。然而，现实世界对环境的感知依赖于多种感官信息的整合。传统上，这种多感觉处理被专门分配到大脑的高级汇聚区域，如上丘或前额皮质，神经元在那里接收来自不同感觉的输入并将它们组合起来。这一概念最近受到了跨模态处理在假定的感觉新皮层区域的挑战。我们最近证明了神经网络振荡和初级感觉皮层之间的直接连接以及皮层下前馈相互作用在视觉-体感处理中的关键作用。然而，跨模态加工的潜在机制和这些相互作用的个体发生在很大程度上仍然未知。本研究的目的是阐明这些问题，重点关注在大鼠脑内的视觉和触觉信息的收敛。在第一步，将同时进行来自初级感觉皮层和丘脑核的细胞外记录，以表征皮层下前馈相互作用在跨模态处理中的作用。其次，我们将确定多感官体验对于皮层和皮层下视觉-触觉相互作用的成熟是否是必要的。第三，我们将确定在定义的发育阶段（关键时期）的无感觉经验是否对多感觉知觉基础的皮层和皮层下视觉-触觉相互作用的成熟是必要的。

While sensory processing represents a constant research topic in neuroscience, its investigation has been mainly achieved by considering a single sensory modality at a time. However, real-world perception of the environment relies on the integration of information from multiple senses. Traditionally, this multisensory processing has been exclusively assigned to higher convergence areas in the brain, such as the superior colliculus or prefrontal cortex, where neurons receive inputs from different senses and combine them. This concept has been recently challenged by the identification of cross-modal processing in putatively unisensory neocortical regions. We recently demonstrated the critical role of neural network oscillations and direct connectivity between primary sensory cortices as well as of subcortical feedforward interactions in visual-somatosensory processing. However, the underlying mechanisms of cross-modal processing and the ontogeny of these interactions remain largely unknown. The present proposal aims at elucidating these issues by focusing on the sparsely investigated convergence of visual and tactile information in the rat brain in vivo. In a first step, simultaneous extracellular recordings from primary sensory cortices and thalamic nuclei will be conducted to characterize the role of subcortical feedforward interactions in cross-modal processing. Second, we will decide whether multisensory experience is necessary for the maturation of cortical and subcortical visual-tactile interactions. Third, we will decide whether unisensory experience during defined developmental stages (critical periods) is mandatory for the maturation of cortical and subcortical visual-tactile interactions underlying multisensory perception.