TitleNeuromodulation of inhibitory feedback to pacemaker neurons and its consequent role in stabilizing the output of the neuronal network
NameZhao, Shunbing (author), Nadim, Farzan (chair), Golowasch, Jorge (internal member), Bose, Amitabha (internal member), Mouser, Christina (outside member), Rutgers University, Graduate School - Newark,
Neural networks (Neurobiology),
DescriptionStable oscillations can be important for the proper function of neuronal networks. Rhythmic movements, for example, often rely on stable input from central pattern generator (CPG) networks that generate the underlying oscillations. I used the crustacean pyloric motor network as a model oscillatory neural system. The primary goal is to characterize the effects of the neuropeptide proctolin on the LP to PD synapse and consequently to investigate functional role in shaping the network output.
First, I characterized the effects of proctolin on both the spike-mediated and graded components of the LP to PD synapse. The results showed that both components of the LP to PD synapse were enhanced by bath-applied proctolin. The results also showed that proctolin caused facilitation of the LP to PD synapse with injection of low amplitude depolarization steps. This facilitation is associated with a slow inward Ca 2+ like current.
Second, I investigated the function of the LP to PD synapse in the pyloric network. The results showed that the LP to PD synapse reduced the variability in the pyloric period. Also, analysis of the phase response curve (PRC) showed that the LP to PD synapse reduced the effect of perturbations. We used synaptic-PRC and its relationship with synaptic phase and synaptic duty cycle to explain how the LP to PD synapse counteracts the effect of perturbation.
Third, I examined the role of proctolin in shaping the neural network output. It was found that in the presence of proctolin the variability of pyloric period was reduced. Furthermore, using PRC analysis, I demonstrated that proctolin reduced the effect of extrinsic perturbations on the pacemaker neurons in the presence of LP to PD synapse. The results suggest that proctolin, through its enhancement on the LP to PD synapse, plays an active role in stabilizing the pyloric network oscillation.
Our findings suggest that modulations of the inhibitory feedback synapse can be a useful approach to regulate the stability of neuronal networks. Insights gained from this thesis could be applied to mammalian nervous system such as feedback or recurrent inhibitory circuits in cortex or oscillator-driven respiratory CPGs.
NoteIncludes bibliographical references (p. 107-114)
Noteby Shunbing Zhao
CollectionGraduate School - Newark Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.