Anatomical, neural, and computational constraints on sensory cross-modal plasticity following early blindness

项目摘要/摘要 早期失明导致人脑内戏剧性的神经可塑性；解剖和功能组织 几乎在每个层面上都会发生变化，从神经递质平衡到神经功能。我计划联合起来 心理物理学，计算功能磁共振成像(FMRI)，扩散加权磁共振成像 (DMRI)和磁共振波谱(MRS)，以研究解剖、神经和计算限制 早期失明后的可塑性。这一建议是由一种假设驱动的，即大脑皮质可塑性是由 早期失明可能与神经元再循环有许多相同的潜在机制，即 新奇的皮质功能的发展(如视力正常的人阅读)依赖于大脑 最初为不同但相似的功能而进化的较老的电路。 我计划在视觉运动区HMT+内的跨模式可塑性的背景下来检验这个想法。面积 在有视力的人中，HMT+处理视觉运动，在早期盲人中对听觉运动做出选择性反应 个人。在目标1中，使用dMRI和fMRI的组合，我将检查跨模式反应是否 早期盲人HMT+内的听觉运动与先前存在的解剖连接共同定位 在HMT+和听觉运动区右颞面(RPT)之间。在目标2中，我将检验假设 EB中的听觉运动处理受到HMT+内时空调谐的影响，使用 心理物理学和功能核磁共振的结合。在目标2中，我还将研究招募HMT+用于 早期盲人的听觉运动处理导致RPT对听觉运动的敏感性丧失。 最后，在目标3中，使用心理物理学和功能磁共振的组合，我将看看HMT+的听觉运动反应 可以用被广泛用于对HMT+建模的分裂归一化经典模型来解释 视力正常个体的视觉运动反应。通过包括MRS GABA测量，我将进一步测试 与听觉运动输入而不是视觉运动输入相关的较低的信噪比导致自适应降低 在抑制中，由较低的GABA浓度介导。 培训的重点是计算功能磁共振成像、dMRI和MRS，这将增强我在 使用心理物理学和建模来表征不同的人类感知经验。我的导师们在 华盛顿大学(Ione Fine博士、Ariel Rokem博士和Scott Murray博士)将在所有 这项提案中使用的技术。这个奖项将为我提供一个重要的机会，让我在 作为一名独立研究员，我在该领域拥有强大的研究计划，调查 视觉剥夺后可塑性的神经解剖学基础。

Project Summary/Abstract Early blindness results in dramatic neuroplasticity within the human brain; anatomical and functional organization is altered at almost every level, ranging from neurotransmitter balance to neural function. I plan to combine psychophysics, computational functional magnetic resonance imaging (fMRI), diffusion-weighted MR imaging (dMRI), and MR spectroscopy (MRS) to investigate the anatomical, neural, and computational constraints of plasticity following early blindness. This proposal is driven by the hypothesis that cortical plasticity resulting from early blindness may share many of the same underlying mechanisms as ‘neuronal recycling, whereby the development of novel cortical functions (such as reading in sighted individuals) relies on the ‘recycling’ of evolutionarily older circuits that originally evolved for different, but similar, functions. I plan to examine this idea in the context of cross-modal plasticity within the visual motion area hMT+. Area hMT+, which processes visual motion in sighted individuals, responds selectively to auditory motion in early blind individuals. In Aim 1, using a combination of dMRI and fMRI, I will examine if the cross-modal responses to auditory motion within hMT+ in early blind individuals co-localizes with pre-existing anatomical connectivity between hMT+ and the auditory motion area right planum temporale (rPT). In Aim 2, I will test the hypothesis that auditory motion processing in EB is influenced by the spatiotemporal tuning within hMT+, using a combination of psychophysics and fMRI. In Aim 2, I will also examine whether the recruitment of hMT+ for auditory motion processing in early blind individuals results in a loss of sensitivity to auditory motion in rPT. Finally, in Aim 3, using a combination of psychophysics and fMRI, I will see if auditory motion responses in hMT+ can be explained by a classic model of divisive normalization that has been extensively used to model hMT+ visual motion responses in sighted individuals. By including MRS GABA measurements, I will further test whether the lower signal to noise associated with auditory rather than visual motion input results in an adaptive reduction in suppression, mediated by lower GABA concentrations. The training will focus on computational fMRI, dMRI, and MRS, which will augment my background in characterizing diverse human perceptual experiences using psychophysics and modeling. My mentors at the University of Washington (Drs. Ione Fine, Ariel Rokem, and Scott Murray) will provide excellent training in all the techniques used in this proposal. The award will provide an important opportunity for me to uniquely position myself in the field as an independent researcher with a strong research program that investigates the neuroanatomical basis of plasticity following visual deprivation.