Crossmodal recruitment of visual and auditory cortex for tactile perception

描述（由申请人提供）： 该申请要求3年的资金，以支持在行为，脑刺激和神经成像技术的个人博士后培训。拟议的工作将采用最先进的方法，如并发TMS功能磁共振成像和非侵入性神经调节，以调查健康人类感觉脑区的跨模态招聘。对盲人和聋人的研究表明，视觉皮层（VC）和听觉皮层（AC）可以单独对触觉刺激做出反应。这种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，跨模态募集unisensory区域的证据相当少-在某些情况下，触觉刺激可以引起VC和AC的神经活动，但这种活动的行为意义尚不清楚。在典型发育中的大脑中，单一感觉区域的跨模态招募挑战了皮层组织的流行的分层模型。正确解释跨模态募集对于更完整地理解感觉处理至关重要，并可能为治疗感觉缺陷提供新的康复干预措施。该建议的主要目标是描述触觉刺激感知过程中体感皮层（SC）与VC和AC之间的相互作用。阳极tDCS将用于解决具体目标1：VC和AC的触觉形状和频率感知的贡献将在心理物理实验中揭示。在用阳极tDCS增强VC和AC兴奋性之前、期间和之后，将评估受试者的触觉空间敏锐度和频率敏感度。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。同步TMS-fMRI将用于解决特定目标2：在受试者区分触觉刺激特征的同时，同时进行全脑成像和SC的局灶性刺激，将直接揭示SC与涉及触觉定向和频率感知的皮质网络之间的注意力调制连接。刺激SC将引起BOLD激活VC和AC，如果这些领域的招聘和功能联系在感知触觉刺激方向和时间频率，分别。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。成功完成本培训计划还将巩固申请人在各种单独和组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.