了解由感官之輸入到行為的表現之神經行為是在神經科學上的一個主要任務，而秀麗隱桿線蟲在生物學中是一個標準之模型生物，其體內神經間之連結已被完全了解。秀麗隱桿線蟲能對外在的影響做簡單的行為反應，例如，化學趨向性以及熱趨向性，而負責反應的神經迴路包含了感覺神經元、中間神經元以及運動神經元，是當前的研究課題。在本論文中，我們藉由衍伸的Fitzhugh-Nagumo模型來研究簡單的神經迴路，並且藉由化學突觸進行耦合激發或抑制後細胞，同時藉由閘門之動力學行為來描述神經傳導物受器之動力學行為，並利用參數之調控以達到突觸之區別。在我們的神經迴路研究中，我們觀察到頻率增昇、渾沌性的動作電位、異性的神經同步以及週期性的動作電位叢集，我們更將此模型應用在秀麗隱桿線蟲的溫度感應迴路(AWC、AFD以及AIY神經元)，並觀察到對溫度之改變所產生的反應行為。Identifying the neural activity which translates a sensory input into behavioral output isone of the central tasks of neuroscience. The nematode C. elegans serves as a model organismin biology and its connectome of neural connections has been completely mapped.C. elegans are capable of some simple behavior responses to external influences such aschemotaxis and thermotaxis. The responsible neural circuits consisting of sensory neurons,interneurons and motor neurons are subject of recent studies.In this thesis we use an extended Fitzhugh-Nagumo model to study the dynamics of simpleneural circuits. The neurons are coupled via chemical synapses, which can excite andinhibit the post-synaptic neuron. The neurotransmitter-receptor dynamics are governedwith a gating dynamic, which allows for the distinction between fast and slow synapses.In our studies of the neural circuits we find frequency enhancement, chaotic spiking,synchronization of fast and slow firing neurons and periodic bursting. We apply themodel to the temperature sensing circuit of the AWC, AFD and AIY neurons of the C.elegans and reproduce the activity response to temperature change.
