Dynamic Regulation of Tuning in Adult Auditory Cortex

成人听觉皮层调谐的动态调节

• 批准号: 6541653
• 负责人: NORMAN M WEINBERGER
• 金额: $ 31.94万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6541653
• 关键词: acetylcholine; association learning; auditory cortex; auditory discrimination; auditory pathways; auditory stimulus; basal ganglia; behavioral /social science research tag; discrimination learning; laboratory rat; memory; neural information processing; neural plasticity; psychoacoustics; reinforcer; sound frequency

DESCRIPTION (provided by applicant): The goal of this research project is to determine the involvement of the primary auditory cortex (Al) in auditory associative memory (AAM) and to identify the mechanisms of AAM. In contrast to traditional views that Al is a static acoustic processor, research during the past decade has established that learning modifies information processing to specifically emphasize the frequency of a behaviorally acquired important stimulus. Notably, neuronal tuning shifts toward/to the frequency of a tone that signals reinforcement. This plasticity, like memory, is associative, highly specific, rapidly acquired, retained indefinitely and consolidates over time. These tuning shifts increase the cortical area that represents behaviorally important frequencies. Thus, the auditory cortex may use a memory code that connotes behavioral importance by increasing the number of cells tuned to that stimulus. We will evaluate this hypothesis by differentially training groups of rats in simple and complex acoustic tasks, so that a tone gains different levels of behavioral importance, as indexed by levels of correct performance. Subsequent mapping of Al will determine the relationship between the area of frequency representation, other cellular response properties, and learned stimulus importance. The nucleus basalis (NB) and its cholinergic (ACh) projections to the auditory cortex have been deeply implicated as mechanisms of learning-induced plasticity because pairing a tone with NB stimulation produces the same types of plasticity as does behavioral training and atropine applied to the cortex blocks the plasticity. Recent work from our laboratory has revealed that pairing a tone with stimulation of the NB actually induces predicted behavioral AAM. Therefore, we will fully characterize NB-induced AAM in simple and complex tasks, including its ability to facilitate new discrimination learning, and determine its correlated Al plasticity. We will also compare Al plasticity from these two approaches to seek general rules relating behavioral auditory associative memory to representational plasticity in primary auditory cortex. The findings will elucidate cortical mnemonic function and provide a foundation for therapeutic treatments, including recovery of higher auditory function following insult and learning to perceive speech using cochlear implants.

描述（由申请人提供）：该研究项目的目标是确定初级听觉皮层（Al）在听觉联想记忆（AAM）中的参与情况并确定 AAM 的机制。与人工智能是静态声学处理器的传统观点相反，过去十年的研究已经证实，学习会修改信息处理，以特别强调行为获得的重要刺激的频率。值得注意的是，神经元调谐会转向表示强化的音调频率。这种可塑性就像记忆一样，具有联想性、高度特异性、快速获得、无限期保留并随着时间的推移而巩固。这些调谐变化增加了代表行为重要频率的皮质区域。因此，听觉皮层可以通过增加适应该刺激的细胞数量来使用表示行为重要性的记忆代码。我们将通过对不同的老鼠组进行简单和复杂的声学任务进行差异化训练来评估这一假设，以便音调获得不同水平的行为重要性，如正确表现水平所指示的。 Al 的后续映射将确定频率表示区域、其他细胞响应特性和学习刺激重要性之间的关系。基底核 (NB) 及其对听觉皮层的胆碱能 (ACh) 投射与学习诱发的可塑性机制密切相关，因为将音调与 NB 刺激配对会产生与行为训练和阿托品应用于听觉皮层相同类型的可塑性。皮质阻碍可塑性。我们实验室最近的工作表明，将音调与 NB 刺激配对实际上会诱导预测的行为 AAM。因此，我们将在简单和复杂的任务中充分表征 NB 诱导的 AAM，包括其促进新辨别学习的能力，并确定其相关的 Al 可塑性。我们还将比较这两种方法的人工智能可塑性，以寻求将行为听觉联想记忆与初级听觉皮层的表征可塑性相关的一般规则。这些发现将阐明皮质记忆功能，并为治疗提供基础，包括在损伤后恢复较高的听觉功能以及学习使用人工耳蜗感知语音。