Weinberger Norman M
Center for the Neurobiology of Learning and Memory, Department of Neurobiology and Behavior, University of California, Irvine, CA 92797-3800, USA.
Hear Res. 2007 Jul;229(1-2):54-68. doi: 10.1016/j.heares.2007.01.004. Epub 2007 Jan 17.
Historically, the primary auditory cortex has been largely ignored as a substrate of auditory memory, perhaps because studies of associative learning could not reveal the plasticity of receptive fields (RFs). The use of a unified experimental design, in which RFs are obtained before and after standard training (e.g., classical and instrumental conditioning) revealed associative representational plasticity, characterized by facilitation of responses to tonal conditioned stimuli (CSs) at the expense of other frequencies, producing CS-specific tuning shifts. Associative representational plasticity (ARP) possesses the major attributes of associative memory: it is highly specific, discriminative, rapidly acquired, consolidates over hours and days and can be retained indefinitely. The nucleus basalis cholinergic system is sufficient both for the induction of ARP and for the induction of specific auditory memory, including control of the amount of remembered acoustic details. Extant controversies regarding the form, function and neural substrates of ARP appear largely to reflect different assumptions, which are explicitly discussed. The view that the forms of plasticity are task dependent is supported by ongoing studies in which auditory learning involves CS-specific decreases in threshold or bandwidth without affecting frequency tuning. Future research needs to focus on the factors that determine ARP and their functions in hearing and in auditory memory.
从历史上看，初级听觉皮层在很大程度上被忽视作为听觉记忆的基质，这可能是因为对联想学习的研究无法揭示感受野（RFs）的可塑性。使用统一的实验设计，即在标准训练（如经典条件反射和操作性条件反射）前后获取RFs，揭示了联想表征可塑性，其特征是对音调条件刺激（CSs）的反应增强，而以其他频率为代价，产生特定于CS的调谐转移。联想表征可塑性（ARP）具有联想记忆的主要属性：它具有高度特异性、辨别性、快速习得、在数小时和数天内巩固，并且可以无限期保留。基底核胆碱能系统对于ARP的诱导以及特定听觉记忆的诱导都是充分的，包括对记忆的声学细节量的控制。关于ARP的形式、功能和神经基质的现有争议似乎在很大程度上反映了不同的假设，本文对此进行了明确讨论。可塑性形式取决于任务的观点得到了正在进行的研究的支持，在这些研究中，听觉学习涉及特定于CS的阈值或带宽降低，而不影响频率调谐。未来的研究需要关注决定ARP的因素及其在听觉和听觉记忆中的功能。
