Reaction to neural signatures through excitatory synapses in central pattern generator models

2007 ◽  
Vol 70 (10-12) ◽  
pp. 1797-1801 ◽  
Author(s):  
Roberto Latorre ◽  
Francisco de Borja Rodríguez ◽  
Pablo Varona
Keyword(s):  
Central Pattern Generator ◽  
Pattern Generator ◽  
Excitatory Synapses ◽  
Neural Signatures

scholarly journals Animal-to-animal variability in the phasing of the crustacean cardiac motor pattern: an experimental and computational analysis

2013 ◽  
Vol 109 (10) ◽  
pp. 2451-2465 ◽  
Author(s):  
Alex H. Williams ◽  
Molly A. Kwiatkowski ◽  
Adam L. Mortimer ◽  
Eve Marder ◽  
Mary Lou Zeeman ◽  
...  
Keyword(s):  
Central Pattern Generator ◽  
Motor Pattern ◽  
Random Parameter ◽  
Homarus Americanus ◽  
Pattern Generator ◽  
Small Cells ◽  
Excitatory Synapses ◽  
Cycle Frequency ◽  
Duty Cycles

The cardiac ganglion (CG) of Homarus americanus is a central pattern generator that consists of two oscillatory groups of neurons: “small cells” (SCs) and “large cells” (LCs). We have shown that SCs and LCs begin their bursts nearly simultaneously but end their bursts at variable phases. This variability contrasts with many other central pattern generator systems in which phase is well maintained. To determine both the consequences of this variability and how CG phasing is controlled, we modeled the CG as a pair of Morris-Lecar oscillators coupled by electrical and excitatory synapses and constructed a database of 15,000 simulated networks using random parameter sets. These simulations, like our experimental results, displayed variable phase relationships, with the bursts beginning together but ending at variable phases. The model suggests that the variable phasing of the pattern has important implications for the functional role of the excitatory synapses. In networks in which the two oscillators had similar duty cycles, the excitatory coupling functioned to increase cycle frequency. In networks with disparate duty cycles, it functioned to decrease network frequency. Overall, we suggest that the phasing of the CG may vary without compromising appropriate motor output and that this variability may critically determine how the network behaves in response to manipulations.

Glutamate as a putative neurotransmitter in the buccal central pattern generator of Helisoma trivolvis

1991 ◽  
Vol 66 (4) ◽  
pp. 1264-1271 ◽  
Author(s):  
E. M. Quinlan ◽  
A. D. Murphy
Keyword(s):  
Central Pattern Generator ◽  
Pattern Generator ◽  
Inhibitory Synapses ◽  
Excitatory Synapses ◽  
Glutamate Receptor Antagonist ◽  
Helisoma Trivolvis ◽  
Postsynaptic Potentials ◽  
Inhibitory Postsynaptic Potentials ◽  
Buccal Ganglia ◽  
Glutamate Agonists

1. The effects of L-glutamate superfusion over identified neurons within the buccal ganglia of Helisoma trivolvis were examined. Glutamate mirrored the effect of activity of subunit 2 (S2) of the tripartite feeding central pattern generator (CPG) on S2 postsynaptic neurons. Neurons that are excited by S2 are depolarized by glutamate, whereas neurons that are inhibited by S2 are hyperpolarized by glutamate. Glutamate also stimulated rhythmic S2 activity. 2. Different glutamate agonists could mimic specific components of the effects of glutamate on buccal neurons. Kainate produced depolarizations in neurons that receive S2 excitatory postsynaptic potentials (EPSPs) and activated rhythmic S2 activity. Quisqualate produced hyperpolarizations in neurons that receive S2 inhibitory postsynaptic potentials (IPSPs). 3. The non-N-methyl-D-aspartate glutamate receptor antagonist cyano-7-nitroquinoxaline-2,3-dione (CNQX) blocked the effects of S2 EPSPs and depolarizations produced by application of glutamate and kainate, but was ineffective in blocking S2 IPSPs or hyperpolarizations produced by application of glutamate and quisqualate. 4. These data support the hypothesis that glutamate is the transmitter of S2 of the feeding CPG in Helisoma, acting at CNQX-sensitive kainate-like receptors at excitatory synapses and CNQX-insensitive quisqualate-like receptors at inhibitory synapses.

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