NEURAL SUBSTRATE OF LEARNING

大脑如何使人能够学习新的行为的问题 奖励反馈的基础是神经科学最伟大的基础之一 挑战。近几十年来的研究已经产生了相当大的 关于控制肌肉方面的神经回路的知识 有关行为和大脑结构的信息 感觉到积极的刺激，但一个部位在 奖赏电路作用于马达控制电路而改变的大脑 未来的行为仍然是个谜。这个项目的目的是 分析大脑中奖赏回路所在部分的连接 和一个相对熟悉的马达电路汇聚在一起，确定 它在学习新行为方面的作用。猴子将被教会到 执行简单的动作，即来回移动眼睛 在视频屏幕上的25个可能的点中有两个目标点。他们 将获得直接脑刺激的奖励，因为 找到正确的一对目标并交替凝视的过程 在这两者之间。研究的目标是(1)确定 大脑中刺激充分的特定区域 奖励动物学会寻找并交替凝视 新的靶点；(2)识别通过的特定神经通路 通过这些区域到达额叶皮质中神经细胞 已知在学习眼球运动时很活跃；及(3) 确定是否使用神经化学药物治疗该区域 暂时扰乱了它的功能，阻止了眼睛的学习 移动到新的目标。两只动物接受了颅骨植入 其中一只经过了充分的测试，证明它学得很快 当受到电刺激时，使眼球运动 丘脑内侧背侧核。

The question of how the brain enables one to learn new behavior on the basis of rewarding feedback is one of neuroscience's greatest challenges. Research in recent decades has produced considerable knowledge about the neurocircuitry that controls the muscular aspect of behavior and about brain structures that are involved in the perception of positive stimulation, but the location of a site in the brain where a reward circuit acts on a motor control circuit to change future behavior remains an enigma. The purpose of this project is to analyze the connections of a part of the brain where a reward circuit and a relatively well-understood motor circuit converge to determine its role in the learning of new behaviors. Monkeys will be taught to perform the simple behavior of moving the eyes back and forth between two target spots out of 25 possible spots on a video screen. They will be rewarded with direct brain stimulation for the time-consuming process of finding the correct pair of targets and gazing alternately between the two. The goals of the research are to (1) identify the specific areas in the brain where stimulation is sufficiently rewarding that the animal learns to find and alternate gaze between new targets; (2) identify the specific nerve pathways that pass through those areas to an area in frontal cortex where nerve cells are known to be active during the learning of eye movements; and (3) determine whether treatment of that area with neurochemical agents that temporarily disrupt its function prevents the learning of eye movements to new targets. Two animals have received cranial implants and one was tested sufficiently to demonstrate that it learned rapidly to make eye movements when rewarded by electrical stimulation of the medial dorsal nucleus of the thalamus.