High Resolution fMRI of Nociception in SII of Monkeys

描述（由申请人提供）：本提案旨在研究非人类灵长类动物中，疼痛和触觉的感觉方面在传统上定义的次级体感皮层（SII）中的皮层表征。通过使用高分辨率fMRI和图像引导电生理记录麻醉松鼠猴，我们将研究SII内的子区域在处理疼痛和触觉输入的基本特征中的功能作用。有两个具体目标。目的1建议确定在单个手指的疼痛和触觉刺激时SII皮层的哪个子区域被激活；痛觉和触觉反应是否在每个激活的子区域内共定位；对于疼痛和/或触摸是否存在细指地形和刺激强度依赖性反应；响应的时间性质是什么。FMRI对疼痛热和振动的激活图将进行比较，以评估激活的特异性。目的2提出确定fMRI显示的激活的神经元机制。FMRI激活图将被验证，并与电生理学确定的图在空间上相关。通过使用功能磁共振成像激活图作为指导，我们将在激活区域放置单个或多个电极，以表征和记录神经元对疼痛热、振动和休息条件的响应特性，并确定神经元活动的哪个方面（单个、多个神经元或局部场电位）与功能磁共振成像信号的刺激-响应功能最相关。本研究将提供关于SII皮层中存在伤害性特定区域以及神经元活动与fMRI信号之间联系的直接证据。最终，所获得的知识将对我们对疼痛处理和感知的细胞机制的理解产生深远的影响。本研究的重点是了解哪些皮质区域对疼痛刺激的位置（在哪里）、强度（有多强）和方式进行编码。如果我们能够理解这些区域在感觉处理过程中是如何组织和激活的，以及它们是如何连接起来形成一个处理网络的，我们就能够理解大脑中信息处理的流程图。这一知识将促进新的治疗理念，这将导致更合理和可靠的治疗疼痛。

DESCRIPTION (provided by applicant): This proposal aims to study the cortical representation of the sensory aspect of pain and touch within the traditionally defined secondary somatosensory cortex (SII) located along the Sylvian fissure in non-human primates. By using high resolution fMRI and image-guided electrophysiological recordings in anesthetized squirrel monkeys, we will examine functional roles of the subregions within SII in the processing of basic features of painful and tactile inputs. There are two specific aims. Aim 1 proposes to determine which subregion(s) within SII cortex is activated during painful and tactile stimulation of individual fingerpads; whether nociceptive and tactile responses colocalize within each activated subregion; whether there is a fine digit topography and stimulus intensity-dependent response for pain and/or touch; and what is the temporal property of the responses. FMRI activation maps to painful heat and vibration will be compared to evaluate the specificity of activation. Aim 2 proposes to determine the neuronal mechanism underlying the activations revealed by fMRI. FMRI activation maps will be validated and spatially correlated with the maps determined by electrophysiology. By using the fMRI activation maps as a guide, we will place single or multiple electrodes in the activated regions to characterize and record neuronal response properties in response to painful heat, vibration, and rest conditions, and to determine what aspect of neuronal activities (single, multiple neuron, or local field potential) correlates best with the stimulus-response function of the fMRI signal. This study will provide direct evidence relating the existence of nociceptive specific regions within SII cortex and the linkage between neuronal activities and fMRI signal. Ultimately, knowledge gained will have profound impact on our understanding of the cellular mechanism of pain processing and perception. 30 PUBLIC HEALTH RELEVANCE This study centers on understanding which cortical areas encode the location (where), intensity (how strong), and modality of a painful stimulus. If we can understand how these areas are organized and activated during sensory processing, and how they are connected to form a processing network, we will be able to understand the flowchart of information processing in the brain. This knowledge would promote new therapeutic ideas, which will lead to more rational and reliable treatment for pain.