Expanded domain of learning-induced primary auditory cortical plasticity

描述（申请人提供）：听觉学习伴随着初级听觉皮层（A1）特定的生理可塑性。通常强调通过学习获得行为重要性的声学频率和其他声学参数的处理和表示，例如，通过选择性地降低阈值或调谐转移到强化刺激的频率。学习诱发听觉可塑性的研究主要集中在确定哪些声学参数会受到影响（如频率、电平、调频调制）。最近的研究表明，有必要考虑到非听觉因素。本研究项目的目标是确定影响联想学习诱发的皮质可塑性的一些因素，并研究这种特定可塑性的发展对功能行为的影响。最初的研究表明，A1特定可塑性的发展不是由学习的大小或绝对频率的学习量决定的，而是由用于解决明显简单的问题的学习策略类型决定的，这取决于音调的存在。我将研究可能在听觉联想记忆中控制初级听觉皮层频率特异性可塑性中发挥重要作用的因素：学习策略和训练量。我还将探讨学习诱导的皮质可塑性可能的行为功能影响：提高知觉可探测性和更强的记忆。用工具条件反射大鼠按bar-press获得基于音调呈现的水奖励，用于研究学习、行为特异性和联想记忆的强度和特异性。在初级听觉皮层的整个大鼠听觉频率范围内的完整电生理记录将用于将调谐变化与行为联系起来。这些发现将有助于阐明学习对特定听觉皮质可塑性（学习策略、训练时间）的一些影响，并建立其与感知行为（条件刺激可探测性）和记忆行为（联想记忆强度）的关系。本研究结果可用于人工耳蜗植入后听觉学习疗法的发展，以帮助获得更高水平的听觉功能。这些实验的结果也可能导致理想的非侵入性治疗的发展，使用学习任务来诱导大脑皮层可塑性，以在中风或其他皮层破坏后恢复功能。

DESCRIPTION (provided by applicant): Auditory learning is accompanied by specific physiological plasticity in the primary auditory cortex (A1). The processing and representation of acoustic frequencies and other acoustic parameters that gain behavioral importance through learning are generally emphasized, e.g., by selective decreased threshold or tuning shifts to the frequency of a reinforced stimulus. Research in learning-induced auditory plasticity has mainly focused on determinations of which acoustic parameters are affected (e.g., frequency, level, FM modulation). Recent studies indicate that there is a need to take into account non-auditory factors. The goals of this research project are to determine some of the factors that influence the induction of associative learning-induced cortical plasticity and to investigate the functional behavioral effects of the development of such specific plasticity. The proposed experiments were designed after initial research showed that the development of specific plasticity in A1 was determined not by the magnitude of learning or the amount of learning about absolute frequency, but rather by the type of learning strategy used to solve the apparently simple problem of bar-pressing for water, contingent on the presence of a tone. I will investigate factors that are likely to play important roles in governing frequency-specific plasticity in the primary auditory cortex in auditory associative memory: learning strategy and amount of training. I will also explore possible behavioral functional effects of learning-induced cortical plasticity: improved perceptual detectability and stronger memory. Instrumental conditioning of rats to bar-press for water rewards contingent upon tone presentations will be used to study learning, specificity of behavior and the strength and specificity of associative memory. Complete electrophysiological recordings across the entire rat hearing frequency range in primary auditory cortex will be used to correlate tuning changes with behavior. The findings will help to illuminate some of the learning influences on specific auditory cortical plasticity (learning strategy, length of training) and establish its relationship to behavior both perceptually (conditioned stimulus detectability) and mnemonically (strength of associative memory). Findings from the proposed studies could be used towards the development of auditory learning therapies for use after artificial cochlear implantation in humans to help acquire higher-level auditory function. The results from the proposed experiments could also lead to the development of ideal non-invasive therapies using learning tasks that induce cortical plasticity for regain of function after stroke, or other cortical destruction.