Spike timing codes for motor control

神经科学的中心目标是了解大脑中的神经活动模式是如何控制行为的。在……里面 原则上，神经元可以通过它们的放电频率、它们尖峰的准确时间或两者来编码信息。 然而，几乎所有先前对运动系统的研究都完全依赖于尖峰频率来调查 大脑控制着行为。我们最近证明，在鸣禽的发声运动皮质中，棘波的计时降至 与SPEK相比，毫秒级的脉冲模式差异更能反映即将到来的行为 费率。虽然这表明皮层棘波时序的变化可以调节行为，但它是未知的。 精确的皮层棘波计时是否在运动神经元和肌肉中驱动类似精确的下游代码 组织，或者实际上运动神经元尖峰时序的变化是否能够改变行为。这个 拟议的实验将结合创新的行为学、生理学和计算技术 为了了解神经系统如何使用精确计时的电活动模式来调节 鸣禽发声输出的声学。我们的长期目标是了解大脑中的尖峰活动 控制行为。本提案的目标是确定马达尖峰驱动变量的哪些特性 在鸣禽发声控制中的行为。我们的中心假设是大脑通过 精确(精确到几毫秒)调制尖峰计时。这一假设将在#年进行检验。 三个具体目标。在目标1中，我们将使用新开发的电极系统来研究来自 肌肉组织(即，单个运动单位的尖峰，每个尖峰由肌肉纤维组成，由 单个运动神经元)在鸣禽发声，以确定神经肌肉控制的时间尺度。在目标2中，我们 将使用创新的体内、体外和体外技术来确定尖峰时间的差异 在肌肉纤维中观察到的会影响运动输出。在目标3中，我们将研究射击模式的精确度 在多块肌肉上协调。这三个目标都将把实验研究和计算紧密地结合在一起 分析以确定对行为影响最大的特定尖峰计时模式，并生成和测试 关于精确运动控制的生物力学基础的假说。这些研究的基本原理是它们 将颠覆长期以来认为大脑皮质运动控制完全基于峰速代码的观念，并建立一个广泛的 适用的框架，用于分析电机系统内外基于定时的尖峰代码。 此外，我们的发现和技术可能会对神经假体的改进做出重大贡献。 设备，通过展示解码算法如何利用速率信息之外的尖峰定时 通常在当前方法中使用。

A central goal of neuroscience is to understand how patterns of neural activity in the brain control behavior. In principle, neurons can encode information via their firing rates, the precise timing of their spikes, or both. However, nearly all prior studies of motor systems have relied exclusively on spike rates to investigate how the brain controls behavior. We recently demonstrated that in songbird vocal motor cortex, spike timing – down to millisecond-scale differences in spike patterning – is far more informative about upcoming behavior than is spike rate. Although this suggests that variations in cortical spike timing could modulate behavior, it is unknown whether precise cortical spike timing drives a similarly precise code downstream in motor neurons and muscle tissue, or indeed whether variations in motor neuron spike timing are capable of modifying behavior. The proposed experiments will combine innovative behavioral, physiological, and computational techniques to understand how the nervous system uses precisely timed patterns of electrical activity to regulate the acoustics of vocal output in songbirds. Our long-term goal is to understand how spiking activity in the brain controls behavior. The objective of this proposal is to determine which properties of motor spiking drive variations in behavior in control of vocalizations in songbirds. Our central hypothesis is that the brain controls behavior by precisely (down to a precision of a few milliseconds) modulating spike timing. This hypothesis will be tested in three specific Aims. In Aim 1, we will use a newly developed electrode system to study spiking activity from muscle tissue (i.e., the spikes of individual motor units, each of which consists muscle fibers innervated by a single motor neuron) in vocalizing songbirds to determine the timescale of neuromuscular control. In Aim 2, we will use innovative in vivo, in vitro, and ex vivo techniques to determine whether spike-timing differences observed in muscle fibers affect motor output. In Aim 3, we will examine how precise firing patterns are coordinated across multiple muscles. All three Aims will tightly integrate experimental studies and computational analyses to identify specific spike timing patterns that most strongly influence behavior and to generate and test hypotheses about the biomechanical bases of precise motor control. The rationale for these studies is that they will upend long-held notions that cortical motor control is based solely on spike rate codes and establish a broadly applicable framework for analyzing timing-based spike codes both within and beyond the motor system. Furthermore, our findings and techniques may significantly contribute to the improvement of neural prosthetic devices by showing how decoding algorithms might make use of spike timing in addition to the rate information commonly used in current approaches.