Ying Rose, Stolzberg Daniel J, Caras Melissa L
Neuroscience and Cognitive Science Program, University of Maryland, College Park, Maryland 20742
Department of Biology, University of Maryland, College Park, Maryland 20742.
J Neurosci. 2025 Mar 5;45(10):e0691242024. doi: 10.1523/JNEUROSCI.0691-24.2024.
Hearing is an active process in which listeners must detect and identify sounds, segregate and discriminate stimulus features, and extract their behavioral relevance. Adaptive changes in sound detection can emerge rapidly, during sudden shifts in acoustic or environmental context, or more slowly as a result of practice. Although we know that context- and learning-dependent changes in the sensitivity of auditory cortical (ACX) neurons support many aspects of perceptual plasticity, the contribution of subcortical auditory regions to this process is less understood. Here, we recorded single- and multiunit activity from the central nucleus of the inferior colliculus (ICC) and the ventral subdivision of the medial geniculate nucleus (MGV) of male and female Mongolian gerbils under two different behavioral contexts: as animals performed an amplitude modulation (AM) detection task and as they were passively exposed to AM sounds. Using a signal detection framework to estimate neurometric sensitivity, we found that neural thresholds in both regions improve during task performance, and this improvement is largely driven by changes in the firing rate rather than phase locking. We also found that ICC and MGV neurometric thresholds improve as animals learn to detect small AM depths during a multiday perceptual training paradigm. Finally, we revealed that in the MGV, but not the ICC, context-dependent enhancements in AM sensitivity grow stronger during perceptual training, mirroring prior observations in the ACX. Together, our results suggest that the auditory midbrain and thalamus contribute to changes in sound processing and perception over rapid and slow timescales.
听觉是一个主动过程，在此过程中，聆听者必须检测和识别声音，分离并辨别刺激特征，并提取其行为相关性。声音检测中的适应性变化可在声学或环境背景突然变化时迅速出现，或因练习而更缓慢地出现。尽管我们知道听觉皮层（ACX）神经元敏感性的上下文和学习依赖性变化支持感知可塑性的许多方面，但人们对皮层下听觉区域在此过程中的贡献了解较少。在这里，我们在两种不同的行为背景下记录了雄性和雌性蒙古沙鼠下丘中央核（ICC）和内侧膝状核腹侧亚区（MGV）的单神经元和多神经元活动：动物执行调幅（AM）检测任务时以及被动暴露于AM声音时。使用信号检测框架来估计神经测量敏感性，我们发现两个区域的神经阈值在任务执行期间都会提高，并且这种提高很大程度上是由放电率的变化而非锁相驱动的。我们还发现，在多天的感知训练范式中，随着动物学会检测小的调幅深度，ICC和MGV的神经测量阈值会提高。最后，我们发现，在MGV而非ICC中，AM敏感性的上下文依赖性增强在感知训练期间变得更强，这与之前在ACX中的观察结果一致。总之，我们的结果表明，听觉中脑和丘脑在快速和缓慢的时间尺度上对声音处理和感知的变化有贡献。
