Regulation of membrane voltage oscillation on rhythmic firing of spinal interneurons
A model involving two cat spinal interneurons is established to investigate the effects of ion channels on the rhythmic generation in spinal interneurons during the membrane voltage oscillation.In the model,the interneurons are connected with each other through reciprocal inhibition,and can produce rhythmic firing when stimulated by excitation.The established model is used to study the changes in the excitability and rhythmicity of the neurons under 3 conditions,including synapse input with white noise(WN group),channel flicker added to ion channels(CF group),and white noise plus channel flicker(WN+CF group),and to quantify the voltage threshold of interneuron rhythmic firing,step duty cycle,and instantaneous firing frequency.The simulation results show that(1)the voltage thresholds are-46.98,-46.48 and-47.00 mV in WN,CF and WN+CF groups,which are 0.47 mV lower,0.03 mV higher and 0.49 mV lower as compared with control group.(2)The instantaneous firing frequencies of extensor in WN,CF and WN+CF groups are 41.28,27.43 and 40.17 Hz,respectively,which are 15.25,1.40 and 14.14 Hz higher than control group;while the instantaneous firing frequencies of flexor are 41.01,27.45,40.20 Hz,which are 15.20,1.64 and 14.39 Hz higher than control group.(3)The frequencies of step period are 0.72,0.68 and 0.68 Hz in WN,CF and WN+CF groups,which are 0.01 Hz higher,0.03 Hz lower and 0.03 Hz lower as compared with control group.(4)The step duty cycles are 49.41%,45.02%and 50.18%in WN,CF and WN+CF groups.Compared with control group,WN group and WN+CF group increased step duty cycles by 4.27%and 5.04%,while CF group decreased it by 0.12%.These results demonstrate the regulations of ion channels on neuronal excitability and locomotor rhythmicity during the membrane oscillation,providing prediction and reference for subsequent physiological experiments.
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