Multisensory Interactions in the Lateral Geniculate Nucleus

描述（由申请人提供）：拟议研究的目的是探索一个激进的想法，即视觉皮层从外侧膝状体核（LGN）接收的主要信息不是纯粹的视觉信息，而是已经由其他感觉方式的信息引发的视觉信息。世纪以来，神经科学家们的主流观点一直是，感觉是在一个连续的过程中形成知觉的。根据这个方案，丘脑的感觉“中继核”（如LGN）只是将每个感觉器官捕获的世界的被动图像提供给相应感觉大脑皮层的一级神经元。皮层的第一级神经元增加得更多，第二级神经元增加得更多，感受器通过皮层层级逐渐建立，然后到达多感觉联合区。在这个提议中，我们假设灵长类动物的大脑能够做出快速而准确的决策，部分原因是它能够从一开始就专注于所有感觉器官输入的相关方面，而不需要欣赏每个感觉器官呈现的所有细节。我们认为，大脑妥协的详细表示和分析的每个感官世界的整体“视图”的世界是多才多艺的，可靠的和高度信息化的指导行为。这需要对每个感觉皮层接收的主要信息进行多模式调制。我们提出了初步的证据来支持这一观点。我们认为，最近的几份报告显示，早期皮层神经元的活动的跨模态调制也支持这一假设。在这个试点工作中，我们将探讨是否存在（1）被动刺激混合（2）外源性注意驱动和（3）内源性注意驱动的跨通道的相互作用，在LGN和系统的特点。我们的具体假设是，跨通道的相互作用发生在最早的结构的感觉通路，如LGN在一个任务依赖的方式。在这个试点项目中，我们将研究这些听觉-视觉交互是否是时空精确的，眼睛相对于头部的位置如何影响这种交互，以及视觉响应的调制是否针对听觉参数进行调整。最后，我们将探讨是否可以获得内源性跨通道注意力的影响，无论是竞争，合作，或两种类型的跨通道线索。如果我们能够支持我们的初步结果，并开始确定多感觉相互作用是如何在感觉丘脑中发生的，我们就可以从根本上改变目前关于大脑最早阶段如何处理信息的观点。 当一种感官，如听觉，因疾病、事故或衰老而丧失时，我们必须科普其余的感官，但一种感官的丧失也可能影响其余的感官。这项研究将揭示大脑中的听觉神经元如何影响视觉神经元的表现，因此，听力损失如何影响视觉，或者视觉和听觉之间的不适当整合如何导致精神分裂症症状。这将导致更有效的治疗。

DESCRIPTION (provided by applicant): The aim of the proposed research is to explore the radical idea that the primary information received by the visual cortex from the lateral geniculate nucleus (LGN) is not purely visual but rather visual information that has already been primed by information from other sensory modalities. For more than a century, the predominant view among neuroscientists has been that sensations are built into perceptions in a serial progression. According to this scheme, sensory "relay nuclei" of the thalamus such as the LGN simply provide a passive image of the world as captured by each sense organ to the first order neurons of the corresponding sensory cerebral cortex. Those first order neurons of the cortex add a bit more, the second order neurons still more and the percept is gradually built up through the cortical hierarchy and thereafter reaches multisensory association areas. In this proposal we hypothesize that the primate brain achieves fast and accurate decision-making in part due its ability to focus, right from the beginning, on relevant aspects of inputs from all sense organs without appreciating all the details presented by each sense organ. We propose that the brain compromises detailed representation and analysis of each sensory world for an overall "view" of the world that is versatile, reliable and highly informative to guide behavior. This requires a multimodal modulation of the primary information received by each sensory cortex. We present preliminary evidence to support this view. We argue that several recent reports showing cross-modal modulation of the activity of early cortical neurons also support this hypothesis. In this pilot effort we will explore the existence of (1) passive stimulus mixing (2) exogenous attention driven and (3) endogenous attention driven cross-modal interactions in the LGN and systematically characterize them. Our specific hypothesis is that cross-modal interactions occur in the earliest structures of the sensory pathway such as the LGN in a task dependent manner. In this pilot project, we will investigate whether these auditory-visual interactions are spatiotemporally precise, how the position of the eye relative to the head influences this interaction, and whether the modulation of visual responses is tuned for auditory parameters. Finally, we will explore whether endogenous crossmodal attentional effects can be obtained either for competing, cooperating, or both types of cross-modal cues. If we are able to support our preliminary results and begin to determine how multisensory interactions occur in sensory thalamus we could radically change current views of how information is processed at the earliest stages in the brain. PUBLIC HEALTH RELEVANCE When one sense, such as hearing, is lost due to disease, accident, or ageing, we must cope with the remaining senses, but the loss of one sense could impact the remaining senses also. This research will reveal how auditory neurons in the brain influence the performance of visual neurons and, therefore, how hearing loss could impact vision or how inappropriate integration between vision and audition could lead to schizophrenic symptoms. This will lead to more effective therapies.