CORTICAL PLASTICITY AND PROCESSING OF COMPLEX STIMULI

来自神经科学研究的皮层可塑性的见解已经不可或缺的治疗策略的发展，包括阅读障碍，耳鸣和中风的神经系统疾病。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（如语音）的皮层表征的可塑性原理的理解仍然是初步的。拟议的实验文件如何经验依赖的可塑性提高了听觉皮层表示的频谱时间复杂的刺激，并通过推进我们的理解大脑机制参与语言的学习，将有助于治疗沟通障碍。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，平行于自然学习。所提出的实验将通过将NB刺激与复杂的spectrotemporal刺激配对来扩展该系列。两种不同的编码策略，这表明刺激胆碱能核基础（NB）产生强大的皮质可塑性，平行于自然学习。所提出的实验将通过将NB刺激与复杂的spectrotemporal刺激配对来扩展该系列。两种不同的策略，这已被提出来代表记忆的神经基础，出现与行为重要的复杂刺激的自然学习。在第一种情况下，复杂特征由神经元的分布式活动表示（粗编码）;而在第二种情况下，复杂刺激由调整到特定谱时转换的专门滤波器表示（稀疏编码）。我们的初步证据表明，NB刺激导致表征可塑性，结合两种编码策略。除了锐化频谱和时间响应一般，NB激活配对spectrotemporal序列创建组合选择性神经反应，不存在于幼稚皮层。这些结果表明，组合的选择性并不限于物种/特定的发声，和表示的声学环境。我们将继续研究其他几种声音刺激，以准确地确定在我们的初步结果中观察到的产生表征可塑性的每个元素所需的刺激特征。

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.