Functions of the Thalamus in Perception and Cognition

描述(由申请人提供)：在使用脑功能图谱技术了解人类选择性注意、记忆或决策的认知功能的神经基础方面取得了很大进展，并利用单细胞生理学和其他侵入性技术在猕猴作为人脑功能的原型动物模型方面取得了很大进展。这些研究几乎完全集中在大脑皮层的感觉和高级处理区域。相比之下，对丘脑外侧膝状核(LGN)等丘脑核团在感知和认知中的作用知之甚少。传统上，LGN被认为是通往初级视觉皮质的门户，它将视觉信息忠实地从视网膜传递到皮质，而不需要太多的调节。这项研究的目的是通过研究LGN在与视觉意识相关的知觉功能和与选择性注意相关的认知功能中的功能作用来挑战这一传统观点。这项研究的中心假设是，LGN在视觉注意和意识中扮演着比中继核更重要的角色，充当着守门人的角色。在非受损者和阅读障碍受试者中进行fMRI和行为学研究是为了解决以下问题：1)能否早在LGN的小细胞或大细胞部分识别意识知觉的神经关联？2)选择性注意控制在人类LGN获得的神经机制是什么，这种获得控制是否仅限于大细胞LGN？3)阅读障碍受试者的视觉加工异常和注意缺陷是否与大细胞LGN的功能紊乱有关？在人脑中，由于空间分辨率和脑图技术的信噪比限制，研究皮质下核团已被证明是困难的。这项拟议的研究将使用创新的高分辨率和超分辨率人体成像技术来克服其中的一些问题。大脑皮层在很大程度上依赖于它从丘脑接收到的信息，因为它接收的其他信息很少。了解皮质功能依赖于了解丘脑输入，而丘脑输入是皮质处理的必要第一步。

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.