Stochastic Nonlinear Dynamics of Sensory Nervous Systems

描述：(申请人提供)拟议研究的长期目标是更好地了解非线性和随机过程在脊椎动物感觉神经系统信息处理的神经机制中的功能作用。我们将利用白对虾的电感受器作为一个有利的实验模型来研究感觉系统的一般基本机制，特别是涉及振荡、爆发、噪声、同步和随机共振的机制。白对虾是一种新发展起来的模型系统，在感觉神经整合的研究中表现出独特的实验优势。我们最近发现，电感受器具有一种新的双周期结构：它们有两种不同类型的自维持振荡器，一种在初级传入细胞中以40-70赫兹的频率循环，另一种在电敏性上皮细胞中以25-30赫兹的频率振荡。这两种类型的振荡器通过毛细胞-传入兴奋性突触进行单向耦合。因此，电感受器提供了一个定义明确的外周振荡神经网络，用于定义非线性和随机的感觉机制。这一建议包括实验神经生理学、行为生物学和计算神经科学的组成部分，并基于随机非线性系统的物理理论。我们将在不同的水平上研究白对虾的电感觉系统，使用：(I)体外准备以获得毛细胞和传入终末振荡的结构基础和细胞机制的信息，(Ii)活体准备和从非线性动力学的方法来表征电感受器的反应动力学，它们的转移和感觉编码特性，随机共振，同步，和噪声诱导的刺激编码到突发模式的转变，(Iii)摄食行为实验来证实所提出的感觉编码规则的有效性，以及(Iv)理论和计算机建模来数值地探索神经传感器中振荡活动的功能角色。这项研究旨在更好地了解毛细胞初级传入感觉受体的基本生理特性，包括那些调节人类听力和平衡的受体，以及振荡神经网络中感觉处理的一般基本机制，包括人类的视觉、嗅觉、听觉和躯体感觉系统，以及癫痫和帕金森患者的紊乱网络。

DESCRIPTION: (provided by applicant) The long-term objective of the proposed research is to gain a better understanding of the functional roles of nonlinear and stochastic processes in neural mechanisms of information processing in the sensory nervous systems of vertebrates. We will use the electro-receptors of paddlefish as an advantageous experimental model for studying general basic mechanisms of sensory systems, especially mechanisms involving oscillations, bursting, noise, synchronization, and stochastic resonance. Paddlefish are a newly developed model system presenting unique experimental advantages for studying sensorineural integration. We discovered recently that electro-receptors have a novel bi-periodic organization: they have two distinct types of self-sustained oscillators, one cycling at 40-70 Hz in the primary afferent, together with 25-30 Hz oscillators in the electro-sensitive epithelium. The two types of oscillators are coupled uni-directionally by hair cell -to- afferent excitatory synapses. Electro-receptors therefore offer a well-defined peripheral oscillatory neural network for defining nonlinear and stochastic sensory mechanisms. This proposal includes components of experimental neurophysiology, behavioral biology, and computational neuroscience, and is based on physical theory of stochastic nonlinear systems. We will study the electro-sensory system of paddlefish on different levels, using: (i) in vitro preparations to gain information about the structural basis and cellular mechanisms of oscillations in hair cells and afferent terminals, (ii) in vivo preparations together with approaches from nonlinear dynamics to characterize the electro-receptor response dynamics, their transfer and sensory encoding properties, stochastic resonance, synchronization, and noise-induced transitions to a bursting mode of stimulus encoding, (iii) feeding behavior experiments to confirm the validity of proposed sensory encoding rules, and (iv) theoretical and computer modeling to explore numerically the functional roles of oscillatory activity in neurosensors. The proposed research is intended to lead to a better understanding of basic physiological properties of hair cell - primary afferent sensory receptors, including those mediating hearing and balance in humans, as well as general fundamental mechanisms of sensory processing in oscillatory neural networks, which include the human visual, olfactory, auditory, and somatosensory systems, as well as the disordered networks of epileptic and Parkinsonian patients.