DYNAMIC REGULATION OF TUNING IN ADULT AUDITORY CORTEX

描述：现在已知成人的听觉皮层是 动态调节，与传统的信念相反， 生理静态。 一个主要的调节因素是学习行为 声音的重要性。 学习改变了对频率的处理 信息，并以一种特别强调频率的方式这样做， 一种行为上获得的重要刺激。 这个结论是基于 在人类和动物中发现， 刺激，代表刺激增加的区域和 细胞对刺激的频率调节。 这种调整变化是 联想性，高频率特异性，发展迅速，持续 无限期 因此，听觉皮层的功能组织 既反映了声音的物理参数， 重要性 这种动态调节的机制实际上是 未知 两个主要的候选者是（a）前和后的协方差。 听觉皮层中神经元活动的突触后水平，和（B） 乙酰胆碱（ACh）对听觉皮层的神经调节作用。 具体来说，在成年豚鼠中，我们将（1）控制突触后 通过微细胞的纳米电流在音调呈现期间的反应 微管，（2）刺激核团的双音呈现 基底肌是ACh向听觉皮层的来源，（3）阻断胆碱能 行为学习过程中听觉皮层的活动，（4）控制 在基底核存在下的突触后反应 刺激和（5）确定对各种细胞层的影响， 听觉皮层 这些研究对健康有重要意义。 的 听觉皮层对于正常的知觉，特别是对于言语， 这是学习。 利用大脑皮层可塑性的机制 简单的刺激，即，纯净的音调，构成了一个进入更大的 大脑皮层处理复杂刺激的问题，如语音。 此外，该项目将为理解学习提供基础 在聋人中植入人工耳蜗后感知语言， 确定了基于学习的时间处理缺陷的补救措施， 阅读障碍

DESCRIPTION: The auditory cortex in the adult is now known to be dynamically regulated, in contrast to the traditional belief that it is physiologically static. A major regulatory factor is the learned behavioral importance of sound. Learning modifies the processing of frequency information and does so in a way that specifically emphasizes the frequency of a behaviorally acquired important stimulus. This conclusion is based on findings in both humans and animals of increased metabolic response to that stimulus, increased area representing that stimulus and shifts in the frequency tuning of cells to that stimulus. Such tuning changes are associative, highly frequency specific, develop rapidly and last indefinitely. Thus, the functional organization of the auditory cortex reflects both the physical parameters of sound and their acquired behavioral importance. The mechanisms of this dynamic regulation are virtually unknown. Two major candidates are (a) the covariance of pre- and post-synaptic levels of neuronal activity in the auditory cortex and (b) the neuromodulatory action of acetylcholine (ACh) on the auditory cortex. Specifically, in adult guinea pigs, we will (1) control postsynaptic response during tone presentation by nano-currents through a juxtacellular micropipette, (2) pair tone presentation with stimulation of nucleus basalis, the source of ACh to the auditory cortex, (3) block cholinergic actions of the auditory cortex during behavioral learning, (4) control postsynaptic response during tome in the presence of nucleus basalis stimulation and (5) determine the effects on various cell layers of the auditory cortex. The studies have important implications for health. The auditory cortex is essential for normal perception, particularly for speech, which is learned. Understanding the mechanisms of cortical plasticity using simple stimuli, i.e., pure tones, constitutes an entry point into the larger problem of cortical processing of complex stimuli, such as speech sounds. Additionally, this project will provide a basis for understanding learning to perceive speech following cochlear implants in the deaf and recently identified learning-based remediation of temporal processing deficits in dyslexia.