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质的特定生理可塑性(A1)。通常强调对通过学习获得行为重要性的声频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移动到增强刺激的频率。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受到影响(例如，频率、电平、FM调制)。最近的研究表明，有必要考虑非听觉因素。本研究项目的目的是确定影响联想学习诱导的皮质可塑性的一些因素，并探讨这种特定可塑性发展的功能行为效应。提出的实验是在最初的研究表明A1中特定可塑性的发展不是由学习的大小或关于绝对频率的学习量决定的，而是由用于解决明显简单的压杆取水问题的学习策略的类型决定的，取决于音调的存在。我将调查可能在控制听觉联想记忆初级听觉皮质的频率特异性可塑性方面发挥重要作用的因素：学习策略和训练量。我还将探索学习诱导的皮质可塑性可能产生的行为功能效应：提高感知能力和增强记忆力。我们将用大鼠的工具性条件反射来研究学习、行为的特异性以及联想记忆的强度和特异性。整个大鼠初级听觉皮质的听觉频率范围内的完整电生理记录将被用来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的一些影响(学习策略、训练时间)，并建立其与行为的知觉(条件刺激检测能力)和记忆力(联想记忆强度)的关系。这项拟议的研究结果可用于开发人工耳蜗术后的听觉学习疗法，以帮助获得更高水平的听觉功能。拟议的实验结果还可能导致开发理想的非侵入性治疗方法，使用诱导皮质可塑性的学习任务，以恢复中风后的功能，或其他皮质破坏。

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.