Crossmodal recruitment of visual and auditory cortex for tactile perception

描述(由申请人提供)： 这项申请需要3年的资金，以支持个人博士后在行为、脑刺激和神经成像技术方面的培训。这项拟议的工作将使用最先进的方法，如并行TMS-fMRI和非侵入性神经调节，来研究健康人类感觉脑区的跨模式招募。对盲人和聋人的研究表明，视觉皮质(VC)和听觉皮质(AC)可以单独对触觉刺激做出反应。这一活动被认为反映了感觉剥夺导致的大脑组织的大规模变化。在典型发育的大脑中，跨模式招募单一感觉区域的证据要少得多-在某些情况下，触觉刺激可以在VC和AC中唤起神经活动，但这一活动的行为意义尚不清楚。在典型发育的大脑中跨模式招募单一感觉区域，挑战了大脑皮层组织的主流分层模型。正确解释跨通道招募对于更完整地理解感觉加工是至关重要的，并可能为治疗感觉缺陷的新的康复干预提供信息。该方案的主要目的是描述触觉刺激知觉过程中躯体感觉皮层(SC)与VC和AC之间的相互作用。阳极tdcs将用于解决特定目标1：将在心理物理实验中揭示VC和AC对触觉形状和频率知觉的贡献。受试者的触觉空间敏锐度和频率敏感度将在阳极tdcs增强VC和AC兴奋性之前、期间和之后进行评估。VC和AC调制导致的触觉阈值的改善将表明这些区域在触觉方向和频率感知中的作用。同时TMS-fMRI将被用于解决特定目标2：同时对SC进行全脑成像和局部刺激，同时受试者辨别触觉刺激特征将直接揭示SC和涉及触觉定向和频率感知的皮质网络之间的注意调节连接。刺激SC将在VC和AC中激起大胆的激活，如果这两个区域分别在触觉刺激方向和时间频率的感知过程中被招募和功能联系在一起。这些实验的结果将进一步加深我们对感觉处理和大脑组织的理解。成功完成这项培训计划还将巩固申请人在各种独立和综合研究方法方面的专业知识，这将使他成为一名成功的独立研究人员。

DESCRIPTION (provided by applicant): This application requests 3 years of funding to support individual post-doctoral training in behavioral, brain stimulation, and neuroimaging techniques. The proposed work will employ state-of-the-art approaches like concurrent TMS-fMRI and noninvasive neuromodulation to investigate crossmodal recruitment of sensory brain areas in healthy humans. Studies with blind and deaf individuals indicate that visual cortex (VC) and auditory cortex (AC) can respond to tactile stimulation alone. This activity is thought to reflect large-scale changes in brain organization resulting from sensory deprivation. There is considerably less evidence for crossmodal recruitment of unisensory areas in typically developing brains - in some instances, tactile stimulation can evoke neural activity in VC and AC, but the behavioral significance of this activity is unclear. Crossmodal recruitment of unisensory areas in typically developing brains challenges prevailing, hierarchical models of cortical organization. Correctly interpreting crossmodal recruitment is critically important for a more complete understanding of sensory processing and may inform novel rehabilitation interventions for treating sensory deficits. This proposal's main objective is to characterize the interactions between somatosensory cortex (SC) and VC and AC during tactile stimulus perception. Anodal tDCS will be used to address Specific Aim 1: the contributions of VC and AC to tactile shape and frequency perception will be revealed in psychophysical experiments. Subjects' tactile spatial acuity and frequency sensitivity will be assessed before, during, and after enhancement of VC and AC excitability with anodal tDCS. Improved tactile thresholds resulting from VC and AC modulation will indicate these areas' roles in tactile orientation and frequency perception. Concurrent TMS- fMRI will be used to address Specific Aim 2: simultaneous whole brain imaging and focal stimulation of SC while subjects discriminate tactile stimulus features will directly reveal attention-modulated connectivity between SC and cortical networks involved in tactile orientation and frequency perception. Stimulation of SC will evoke BOLD activations in VC and AC if these areas are recruited and functionally linked during the perception of tactile stimulus orientation and temporal frequency, respectively. The results of these experiments will further our understanding of sensory processing and brain organization. Successful completion of this training plan will also solidify the Applicant's expertise in a wide variety of separate and combined research methods, which will enable him to become a successful independent researcher.