Motor Systems Supporting Pavlovian Conditioning

支持巴甫洛夫调节的运动系统

基本信息

批准号：
6772089
负责人：
TERRY J CROW
金额：
$ 29.7万
依托单位：
UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
依托单位国家：
美国
项目类别：
财政年份：
1998
资助国家：
美国
起止时间：
1998-08-01 至 2009-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The long-term objective of this research project is to identify the neural circuit that is responsible for the generation of light-elicited ciliary locomotion and reflex-elicited foot contraction; and to understand how Pavlovian conditioning changes synaptic connections between neurons and alters intrinsic cellular excitability in the circuit. The experiments proposed in this grant will provide insights into how a neural circuit can be modified by Pavlovian conditioning to support the generation of two conditioned responses; CS-elicited foot contraction and conditioned inhibition of light-elicited locomotion. To achieve these goals, a multidisciplinary approach to the study of the cellular and synaptic basis of light-elicited ciliary locomotion and foot contraction will be carried out in the marine mollusk Hermissenda; a preparation that has proven useful in biophysical, biochemical, and molecular studies of learning. One primary goal will be to analyze conductances that contribute to the enhanced intrinsic excitability of the interneurons of conditioned animals using voltage-clamp techniques. We will also further identify neurons in the circuit that supports the generation of light-elicited ciliary locomotion and reflex-elicited contraction of the posterior foot. Using isolated nervous systems, intact animals and semi-intact preparations, we will identify the neural elements of the circuit and determine how the properties of the network contribute to the generation of light-elicited ciliary locomotion and reflex-elicited foot contraction. A second major goal is to determine how the circuit supporting locomotion and reflex-elicited foot contraction can be modified by Pavlovian conditioning. We will examine ciliary activation and statocyst-elicited foot contraction in semi-intact preparations while recording from interneurons and pedal motor neurons. Interneurons that receive sensory input from identified photoreceptors and hair cells, and project to cilia-activating and foot contraction pedal motor neurons will be identified and characterized. We will examine synaptic input to polysensory type I interneurons of conditioned animals to determine how Pavlovian conditioning modifies one sensory input, mediated by the conditioned stimulus (CS), without increasing the responsiveness of the type I interneurons to other sensory inputs. This experimental approach will expand our understanding of conditioning in Hermissenda by identifying within the neural circuit supporting the generation of behavior, other potential loci of plasticity produced by conditioning and provide the database for understanding how intrinsic cellular and synaptic modifications specific to one modality can be expressed in a circuit that must also support normal polysensory processing. These studies will help to elucidate general principles underlying the organization of polysensory neural systems generating behavior and their modification by learning.

描述（由申请人提供）：该研究项目的长期目标是确定负责产生光引起的纤毛运动和反射引起的足部收缩的神经回路；并了解巴甫洛夫条件反射如何改变神经元之间的突触连接并改变回路中内在的细胞兴奋性。本次资助中提出的实验将深入了解如何通过巴甫洛夫条件反射来修改神经回路，以支持两种条件反应的生成； CS 引起足部收缩并条件性抑制光引起的运动。为了实现这些目标，将在海洋软体动物 Hermissenda 中采用多学科方法来研究光引起的纤毛运动和足部收缩的细胞和突触基础；一种已被证明在学习的生物物理、生物化学和分子研究中有用的制剂。一个主要目标是使用电压钳技术分析有助于增强条件动物中间神经元内在兴奋性的电导。我们还将进一步识别回路中支持光引起的纤毛运动和反射引起的后足收缩的神经元。使用分离的神经系统、完整的动物和半完整的制剂，我们将识别回路的神经元件，并确定网络的特性如何有助于光引起的纤毛运动和反射引起的足部收缩的产生。第二个主要目标是确定如何通过巴甫洛夫调节来修改支持运动和反射引起的足部收缩的电路。我们将检查半完整制剂中的纤毛激活和静囊引起的足部收缩，同时记录中间神经元和踏板运动神经元。将识别和表征从已识别的光感受器和毛细胞接收感觉输入并投射到纤毛激活和足部收缩踏板运动神经元的中间神经元。我们将检查条件动物的多感觉 I 型中间神经元的突触输入，以确定巴甫洛夫条件如何修改由条件刺激 (CS) 介导的一种感觉输入，而不增加 I 型中间神经元对其他感觉输入的反应性。这种实验方法将通过识别支持行为生成的神经回路、条件反射产生的其他潜在可塑性位点来扩展我们对 Hermissenda 条件反射的理解，并提供数据库以了解如何表达特定于一种模式的内在细胞和突触修饰在还必须支持正常多感官处理的电路中。这些研究将有助于阐明多感觉神经系统组织产生行为及其通过学习进行修改的一般原理。