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。动物能够在积极的增强剂、它们之前的感觉环境和导致它们的运动行为之间建立新的联系。这项拟议的研究将使用多个微电极植入技术，在动物获得新联系的整个时期内，同时记录听觉皮质中的大量神经元。具体的目的将是观察学习如何改变感觉背景的听觉皮质表征。这些猴子将接受训练，以辨别短音。当他们开始执行接受奖励的任务时，他们的大脑学习机器就会投入使用，并导致声音的表现方式不可避免地发生变化。数据将被并行收集，根据动物的感知能力和行为任务内外听觉领域神经元的反应特性。植入物在神经系统中的应用在过去十年中有了很大的进步；这项研究将把这项技术应用到学习研究中。在训练的第一阶段，动物将对短音做出反应，这些短音的频率只是高于固定的比较音。初步研究表明，如果目标刺激来自一个固定的范围，那么该频率范围的表示就会增长和强化。在这个初始阶段之后，动物将执行相同的频率辨别任务，使用随机频率进行比较和目标音调点数。对照实验将在幼稚的动物身上重复第一阶段训练的试验，这些动物只是被动的听者。这些研究应该有助于将皮层区域的可塑性属性定义为动态学习神经网络。这类网络最容易理解的是它们的初始连接集和学习规则。这项研究将分离和测试学习规则的不同假说，并将有助于更好地理解大脑皮层在工具性学习和经典条件反射中的适应作用。

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.