NEURAL BASIS OF BEHAVIORAL PLASTICITY IN A SIMPLE SYSTEM

我们研究的长期目标是表征细胞和 分子机制赋予生物体 适应外部环境的变化。 我们尤其 建议确定海洋软体动物加州滨螺 在两种相关的，但截然不同的， 有节奏的行为 我们建立了一个假设模型， 假设，当这种开关是有变化的， 两个单位CPG的活动。 机械传入神经元产生 一个“单位CPG”的必要变化;本体感受神经元 产生第二~单位CPG ~的变化。 我们的工作是， 因此，与任何节奏行为的可塑性研究相关， 必须适应外部环境的变化 协调的方式。 此外，实验提出， 将描述特定的机制，确保感官诱导 （a）不改变供电电路的点火模式; 与正在进行的运动模式相冲突，以及（B）以a 与刺激的具体特征相关的方式 诱导行为改变。 例如，在初步 我们已经描述了一个有趣的机制， 可能在确保感官诱导的变化中发挥作用， 运动程序是阶段特异性的。 我们的数据表明， 神经元在运动程序中有节奏地去极化， 这种去极化促进了突触接触处的信息传递 运动神经元。 我们提出了一个新的假设， 假设CPG诱导的去极化影响感觉神经元 主要有两种方式：（1）主要神经递质的释放， 增强，和（2）肽共递质的释放增强，或 唤起的 因此，我们建议，描述一个新的角色， 肽共传递的神经回路经历 从一种节奏输出到另一种节奏输出的转换。 这些数据将有助于指导未来的研究， 神经调制在电路选择，并可能提供见解， 神经系统的功能障碍，当认知 行为的适当选择所必需的过程被扰乱， 就像强迫症一样

The long term goal of our research is to characterize the cellular and molecular mechanisms that endow an organism with its ability to adapt to changes in the external environment. In particular, we propose to determine how the marine mollusc Aplysia californica makes a switch between two types of related, but distinctly different, rhythmic behaviors. We have developed a hypothetical model that postulates that when this switch is made there are changes in the activity of two unit CPGs'. Mechanoafferent neurons produce the necessary changes in one of the 'unit CPGs'; proprioceptive neurons produce the change in the second ~unit CPGs~. Our work is, therefore, relevant to studies of plasticity in any rhythmic behavior that must accommodate changes in the external environment in a coordinated fashion. Additionally, experiments are proposed that will characterize specific mechanisms that insure that sensory-induced changes in the firing patterns of the feeding circuitry; (a) do not conflict with the ongoing motor pattern, and (b) are exerted in a manner that is related to the specific characteristics of the stimulus inducing the behavioral change. For example, in preliminary experiments we have described an interesting mechanism that is likely to play a role in insuring that sensory-induced changes in motor programs are phase specific. Our data suggest that sensory neurons are rhythmically depolarized during motor programs, and that this depolarization facilitates transmission at synaptic contacts with motor neurons. We propose to test a novel hypothesis that postulates that CPG-induced depolarizations impact sensory neurons in two ways; (1) the release of the primary neurotransmitter is enhanced, and (2) the release of peptide cotransmitters is enhanced or evoked. We propose, therefore, to characterize a novel role for peptide cotransmission in a neural circuit undergoing a transformation from one rhythmic output to another. This data will help guide future studies of the role of neuromodulation in circuit selection, and may provide insights into dysfunctions of the nervous system that occur when cognitive processes necessary for the proper choice of behavior are perturbed, as may be the case with obsessions and compulsions.