Functions of the Thalamus in Perception and Cognition

描述（由申请人提供）：在使用功能性脑映射技术理解人类中与选择性注意、记忆或决策相关的认知功能的神经基础方面，以及在使用单细胞生理学和其他侵入性技术理解作为人类脑功能的原型动物模型的猕猴中，已经取得了很大进展。这些研究几乎完全集中在大脑皮层的感觉和高阶处理区域。相比之下，对丘脑核团（如外侧膝状体核（LGN））在感知和认知中的作用知之甚少。传统上，LGN被认为是初级视皮层的门户，它忠实地将视觉信息从视网膜传递到皮层，而不需要太多的调制。拟议的研究的目标是挑战这一传统的观点，通过调查的视觉意识相关的感知功能和选择性注意相关的认知功能的LGN的功能作用。激发这项研究的中心假设是，LGN在视觉注意和意识中扮演着重要的角色，超越了中继核作为看门人的角色。建议对未受损和诵读困难受试者进行功能磁共振成像和行为研究以解决以下问题：1）是否可以早在LGN的小细胞或大细胞部分中识别意识感知的神经相关物？; 2)选择性注意控制人类LGN增益的神经机制是什么？这种增益控制是否仅限于大细胞LGN？3)阅读障碍患者的视觉处理异常和注意力缺陷是否与大细胞LGN的功能紊乱有关？在人脑中，由于空间分辨率和脑映射技术的信噪比限制，研究皮层下核团已被证明是困难的。拟议的研究将在人类中使用创新的高分辨率和超分辨率成像技术来克服其中的一些问题。大脑皮层主要依赖于从丘脑接收的信息，因为它接收的其他信息很少。理解皮层功能取决于理解丘脑的输入，这是皮层处理过程中必要的第一步。

DESCRIPTION (provided by applicant): Much progress has been made in understanding the neural bases of cognitive functions related to selective attention, memory, or decision making in humans using functional brain mapping techniques and in the macaque as the prototypical animal model for human brain function using single-cell physiology and other invasive techniques. These studies have almost exclusively focused on sensory and higher-order processing areas of the cerebral cortex. In contrast, relatively little is known about the role of thalamic nuclei such as the lateral geniculate nucleus (LGN) in perception and cognition. Traditionally, the LGN has been viewed as the gateway to primary visual cortex, which conveys the visual information faithfully from the retina to cortex without much modulation. The goal of the proposed research is to challenge this traditional view by investigating the functional role of the LGN in perceptual functions related to visual awareness and in cognitive functions related to selective attention. The central hypothesis that motivates this research is that the LGN plays an important role beyond that of a relay nucleus as a gatekeeper in visual attention and awareness. FMRI and behavioral studies in non-impaired and dyslexic subjects are proposed to address the following questions: 1) Can neural correlates of conscious perception be identified as early as in the parvocellular, or magnocellular parts of the LGN?; 2) What is the neural mechanism by which selective attention controls gain in the human LGN, and is this gain control confined to the magnocellular LGN?; 3) Are visual processing abnormalities and attentional deficits in dyslexic subjects associated with a functional disorganization of the magnocellular LGN? In the human brain, it has proven difficult to study subcortical nuclei because of spatial resolution and signal-to-noise limitations of brain mapping techniques. The proposed research will use innovative high- and super-resolution imaging techniques in humans to overcome some of these issues. The cerebral cortex depends critically on the information that it receives from the thalamus, since it receives very little else. Understanding cortical functioning depends on understanding the thalamic inputs that are the necessary first step in cortical processing.