Doctoral Dissertation Research: Hippocampal Modulation of Auditory Representations

在美国国家科学基金会的支持下，奥杜纳和他的顾问格鲁克博士将进行为期一年的调查，研究听觉辨别训练如何影响大脑皮质对复杂声音的表征。自然环境充满了复杂的声音，其中包含各种与行为相关的信息。对声音或图像的学习可以导致感知敏感度的变化，从而促进对行为相关事件的处理。尽管这些变化背后的神经机制还不是很清楚，但它们被认为依赖于大脑自适应地修改其大脑皮层感觉表征的能力。奥杜纳和格鲁克将测量老鼠和人类在训练受试者辨别复杂声音之前和之后对这些声音的电生理反应。大脑皮层和海马体处理的计算模型表明，海马体修改皮质表征以促进学习。研究人员将通过比较正常大鼠和海马区受损大鼠的听觉皮质中学习诱发的代表性变化(以诱发反应的变化来衡量)，来评估海马体在听觉学习中的作用。行为和电生理技术的联合使用，结合毁损技术，将有助于比较人类和其他哺乳动物听觉学习的神经机制。这个项目将展示一种新的方法来评估目前关于大脑皮质和海马体在学习和记忆过程中如何相互作用的理论。这些科学结果应该会为学习和记忆的大脑基础提供新的知识。

With National Science Foundation support, Mr. Orduna and his advisor Dr. Gluck will conduct a year long investigation of how auditory discrimination training affects cortical representations of complex sounds. The natural environment is full of complex sounds containing a variety of information relevant to behavior. Learning about sounds or images can lead to changes in perceptual sensitivities that facilitate the processing of behaviorally relevant events. Although the neural mechanisms underlying these changes are not well understood, they are thought to depend on the brain's capacity to adaptively modify its cortical representations of sensations. Orduna and Gluck will measure electrophysiological responses of rats and humans to complex sounds before and after subjects have been trained to discriminate these sounds. Computational models of cortical and hippocampal processing suggest that the hippocampus modifies cortical representations to facilitate learning. The investigators will evaluate the role of the hippocampus in auditory learning by comparing learning-induced representational changes (measured as changes in evoked responses) in the auditory cortices of normal and hippocampal-lesioned rats. The joint use of behavioral and electrophysiological techniques, in combination with lesion techniques, will facilitate comparisons between the neural mechanisms underlying auditory learning in humans and other mammals. This project will illustrate a new way of evaluating current theories of how the cortex and the hippocampus interact during learning and memory processes. These scientific results should provide new knowledge about the brain basis of learning and memory.