CORTICAL PLASTICITY AND PROCESSING OF COMPLEX STIMULI

皮层可塑性的神经科学研究在许多神经系统疾病的治疗策略的发展中是不可或缺的，包括阅读障碍、耳鸣和中风。然而，由于这些研究大多集中在相对简单的感官刺激上，我们对塑造更复杂刺激（如言语）皮层表征的可塑性原理的理解仍然是初级的。我们提出的实验记录了经验依赖的可塑性如何改善听觉皮层对时间谱复杂刺激的表征，并通过推进我们对涉及语言学习的大脑机制的理解，将有助于交流障碍的治疗。使用简单的刺激，我们已经证明胆碱能基底核（NB）的电刺激产生强大的皮质可塑性，与自然学习相似。拟议的实验将通过将NB刺激与复杂的光谱时间刺激配对来扩展这一系列。两种不同的编码策略，已经证明刺激胆碱能核基础（NB）产生强大的皮质可塑性，与自然学习相似。拟议的实验将通过将NB刺激与复杂的光谱时间刺激配对来扩展这一系列。两种不同的策略，已经提出了代表记忆的神经基础，出现在行为重要的复杂刺激的自然学习。在第一种方法中，复杂特征由神经元的分布活动表示（粗编码）；而在第二种情况下，复杂的刺激是用专门的滤波器来表示的，这些滤波器调谐到特定的光谱时间转换（稀疏编码）。我们的初步证据表明，nb刺激导致结合了两种编码策略的表征可塑性。除了增强光谱和时间反应外，NB激活与光谱时间序列配对还产生了幼稚皮层中不存在的组合选择性神经反应。这些结果表明，组合选择性并不局限于物种/特定的发声，以及声环境的表征。我们将继续研究其他几种声刺激，以准确地确定需要哪些刺激特征来产生我们初步结果中观察到的表征可塑性的每个元素。

The insights derived from neuroscience studies of cortical plasticity have been indispensable in the development of treatment strategies for a number of neurological disorders, including dyslexia, tinnitus, and stroke. However, because most of these studies were focused on relatively simple sensory stimuli, our understanding of the plasticity principles that shape the cortical representation of more complex stimuli, such as speech, remains rudimentary. The proposed experiments document how experience-dependent plasticity improves the auditory cortex representation of spectro temporally complex stimuli and, by advancing our understanding of brain mechanisms involved in the learning of language, will aid in the treatment of communicative disorders. Using simple stimuli, we have demonstrated that electrical stimulation of the cholinergic nucleus basalis (NB) generates robust cortical plasticity that parallels natural learning. The proposed experiments will extend this series by pairing NB stimulation with complex spectrotemporal stimuli. Two different coding strategies, which have demonstrated stimulation of the cholinergic nucleus basis (NB) generates robust cortical plasticity that parallels natural learning. The proposed experiments will extend this series by pairing NB stimulation with complex spectrotemporal stimuli. Two different strategies, which have been proposed to represent the neural basis of memory, emerge with natural learning of behaviorally important complexes stimuli. In the first, complex features are represented by the distributed activity of neurons (coarse coding); while in the second, complex stimuli are represented with specialized filters tuned to specific spectrotemporal transitions (sparse coding). Our preliminary evidences indicates that NB-stimulation leads to representational plasticity that combines both coding strategies. In addition to sharpening spectral and temporal responses generally, NB activation paired with a spectrotemporal sequence created combination selective neural responses that do not exist in naive cortex. These results demonstrate that combination selectivity is not limited to species/specific vocalizations, and representations of the acoustic environment. Our continuing studies will examine several other acoustic stimuli to determine precisely what stimulus features are required to generate each element of representational plasticity observed in our preliminary results.