Effects of Reversible Lesions on Resting fMRI in Awake Macaques

描述（由申请人提供）：该项目研究了功能性磁共振成像（fMRI）的一个新的但鲜为人知的发现，该发现为大脑的基本结构提供了新的见解。功能成像研究表明，相似的非连续脑区在广泛的任务中被共同激活。值得注意的是，许多这些共同激活在受试者休息时被重现。因此，静息状态fMRI （rs-fMRI）被认为反映了任务相关的功能网络。我们很想知道是什么原理维持了这些内在的共激活。大多数功能连接研究都集中在皮层上。包括丘脑在内的深层大脑结构与这些网络有关，但人们对它们可能发挥的确切作用知之甚少。大脑皮层的大部分输入通过丘脑，包括许多感觉信号，小脑和基底神经节的输入。因此，丘脑处于调节或维持功能连接的理想解剖位置。局灶性病变可以揭示功能连接的结构和维持。这一领域的进展主要集中在自然发生的病变上。非人类灵长类动物的实验损伤可以精确地放置，并重复以获得对其效果的统计信心。最近,rs-fMRI

DESCRIPTION (provided by applicant): This project examines a new but poorly understood finding from functional magnetic resonance imaging (fMRI) that is providing new insights into fundamental brain architecture. Functional imaging studies show that similar sets of non-contiguous brain regions are co-activated across a wide range of tasks. Remarkably, many of these co-activations are recapitulated when subjects are at rest. Thus, resting state fMRI (rs-fMRI) is thought to reflect task-related functional networks. It is of great interest to know what principles are responsible for the maintenance of these intrinsic co-activations. Most functional connectivity studies have focused on the cortex. Deep brain structures, including the thalamus, have been implicated in these networks, but little is known regarding exactly what role they might play. Most input to the cerebral cortex passes through the thalamus, including many sensory signals, cerebelar and basal ganglia inputs. As a result, the thalamus is in an ideal anatomical position to regulate or maintain functional connectivity. Focal lesions can reveal much about the structure and maintenance of functional connectivity. Progress in this area has focused on naturally occurring lesions. Experimental lesions in non-human primates can be precisely placed, and repeated to obtain statistical confidence in their effects. Recently, rs-fMRI in non-human primates has revealed cortical networks similar to those observed in humans. Muscimol, a GABAA agonist, can be injected into tissue to inhibit local activity, and the sites of inactivation can be precisely monitored. We propose to use reversible inactivation in the macaque monkey to examine the roles of the thalamus and cortex in maintaining resting state network functional connectivity, and to characterize the effects of inactivation on the networks using novel graph theoretic approaches. This work will shed light on the neuronal underpinnings of cortical connectivity and more generally, may inform rehabilitation approaches for traumatic brain injury and other disorders.