A1 neural basis of frequency discrimination learning

描述（由申请人提供）：本申请概述了对听觉学习机制的直接研究。动物能够在积极的刺激物之间建立新的联系，在它们之前的感觉环境，以及引起它们的运动行为。拟议的研究将使用多个微电极植入技术，在动物获得新关联的整个时期内同时记录听觉皮层中大量神经元的信息。具体的目的是观察听觉皮层对感觉情境的表征是如何被学习改变的。这些猴子将被训练辨别短音。当他们开始执行任务以获得奖励时，他们的大脑学习机制被激活，导致声音表现方式不可避免地发生变化。将并行收集动物的感知能力和行为任务内外听觉场中神经元的反应特性方面的数据。在过去的十年中，神经系统中植入物的使用已经取得了很大的进展;这项研究将应用该技术来研究学习。在训练的第一阶段，动物会对频率比固定比较音调高的短音调做出反应。初步研究表明，如果目标刺激来自一个固定的范围，该频率范围的代表性增长和加强。在该初始阶段之后，动物将使用随机频率进行比较和目标音调进行相同的频率辨别任务。一个对照实验将复制第一阶段的训练试验，在幼稚的动物身上进行，这些动物只是被动的倾听者。这些研究应有助于定义皮质领域的动态学习神经网络的塑性特性。这种网络最容易理解的是它们的初始连接集和学习规则。这项研究将隔离和测试不同的假设学习规则，并将导致更好地了解大脑皮层的适应性作用，无论是在工具性学习和经典条件反射。

DESCRIPTION (provided by applicant): This application outlines a direct study of the mechanisms of auditory learning. Animals are capable of making new associations between positive reinforcers, the sensory context that preceded them, and the motor acts that cause them. The proposed studies will use multiple microelectrode implant technology to record simultaneously from a large number of neurons in auditory cortex throughout a period in which an animal acquires a new association. The specific intent will be to observe how the auditory cortex representation of the sensory context is altered by the learning. The monkeys will be trained to discriminate short sound tones. As they begin to perform the task to receive rewards, their brain learning machinery is engaged and causes unavoidable changes in how sounds are represented. Data will be collected in parallel, in terms of the animal's perceptual capabilities and the response properties of neurons in auditory fields within and outside the behavioral tasks. The use of implants in neural systems has advanced much in the last decade; this study will apply that technology to study learning. In the first phase of training, animals will respond to short tones that are just higher in frequency than fixed comparison tones. Preliminary studies have shown that if the target stimulus comes from a fixed range, the representation of that frequency range grows and intensifies. After this initial phase, the animals will perform the same frequency discrimination task using randomized frequencies for comparison and target tone pips. A control experiment will replicate the trials of the first phase of training in naive animals that are only passive listeners. These studies should contribute to defining the plastic properties of cortical fields as dynamic learning neural networks. Such networks are most easily understood in terms of their initial sets of connections and their learning rules. This study will isolate and test different hypotheses for learning rules, and will lead to a greater understanding of the adaptive role of the cerebral cortex in general, both in instrumental learning and in classical conditioning.