Mechanisms for Internal Models in a Cerebellum-like Circuit

项目概要/摘要 人类和其他动物学习并储存复杂的因果关系模型，这些模型支配着它们的行为。 与世界的互动。这种内部模型对于将模糊和延迟的 将感官数据转化为稳定的感知和协调的运动。例如，区分外部 来自那些自我生成的感官输入可以通过预测 动物自身运动指令的感官后果。尽管它们对双方都有潜在的重要性， 正常的大脑功能和神经系统疾病，它已被证明具有挑战性，以了解内部模型如何 都是在神经回路中实现的。这一更新建议采用了实验性和 模型系统的理论方法-弱电鱼-具有独特的优势， 这个问题我们以前的研究电鱼成功地发展了一个详细的机械模型 在第一阶段的神经元处理在电感觉叶（ELL）预测和抵消了 鱼自身的电器官放电（EOD）。然而，这些研究认为， 这是电感觉系统面临的真正问题的一个版本。在自然条件下， 根据鱼的运动（即， 尾部与皮肤上的电感受器）和由尾部发出的EOD运动命令的时间模式。 鱼.解决这个问题需要一个更复杂的内部模型，类似于那些被认为是在 哺乳动物的大脑此外，过去的模型忽略了ELL电路的关键特征，例如 抑制性突触，这可能发挥关键的功能作用（在ELL和其他脊椎动物的大脑回路）。通过 为了解决这些问题，拟议中的研究将为神经回路如何发挥作用提供一般性的见解。 区分自我产生和外部刺激。拟议的研究还将提供直接联系， 在神经表征、明确的回路、突触可塑性和行为相关系统之间， 水平函数虽然建立这样的联系是神经科学的主要目标，但在这方面的案例仍然相对较少。 它们实际上是可以制造的。

Project Summary/Abstract Humans and other animals learn and store sophisticated models of the causal relationships that govern their interactions with the world. Such internal models are likely critical for transforming ambiguous and delayed sensory data into stable perceptions and coordinated movements. For example, distinguishing external sensory input from those that are self-generated could be accomplished via an internal model that predicts the sensory consequences of an animal’s own motor commands. Despite their potential importance for both normal brain function and neurological disorders, it has proven challenging to understand how internal models are actually implemented in neural circuits. This renewal proposal applies a combination of experimental and theoretical approaches to a model system—the weakly electric fish—with unique advantages for addressing this question. Our previous studies of electric fish were successful in developing a detailed mechanistic model of how neurons at the first stage of processing in the electrosensory lobe (ELL) predict and cancel out the effects of the fish’s own electric organ discharge (EOD). However, these studies considered a highly simplified version of the true problem facing the electrosensory system. Under natural conditions, electrosensory inputs vary moment-to-moment depending both on the movements of the fish (i.e. the position of the electric organ in the tail versus electroreceptors on the skin) and the temporal pattern of EOD motor commands emitted by the fish. Solving this problem requires a more complex internal model, akin to those believed to be generated in the mammalian brain. In addition, past models ignored key features of ELL circuitry, such as plasticity of inhibitory synapses, which likely play key functional roles (both in ELL and in other vertebrate brain circuits). By addressing these issues the proposed research will provide general insights into how neural circuits contribute to distinguishing self-generated from external stimuli. The proposed studies will also provide direct links between neural representations, well-defined circuitry, synaptic plasticity, and a behaviorally relevant systems level function. Though forging such links is a primary goal of neuroscience, there are still relatively few cases in which they can actually be made.