摘要
突触输入刺激神经元产生的电活动,在神经编码中发挥着重要作用.通常认为,兴奋性输入增强电活动,抑制性输入压制电活动.本文选取可调节电流衰减速度的突触模型,研究了兴奋性自突触在亚临界Hopf分岔附近压制神经元电活动的反常作用,与抑制性自突触的压制作用进行了比较,并采用相位响应曲线和相平面分析解释了压制作用的机制.对于单稳的峰放电,快速和中速衰减的兴奋性自突触分别可以诱发频率降低的峰放电和混合振荡(峰放电与阈下振荡的交替),而中速和慢速衰减的抑制性自突触也可以分别诱发频率降低的峰放电和混合振荡.对于与静息共存的峰放电,除上述两种行为外,中速衰减的兴奋性和慢速衰减的抑制性自突触还可以诱发静息.兴奋性和抑制性自突触电流在不同的衰减速度下,分别作用在峰放电的不同相位,才能诱发同类压制行为.结果丰富了兴奋性突触压制电活动反常作用的实例,获得了兴奋性和抑制性自突触压制作用机制的不同,给出了调控神经放电的新手段.
Neural activities driven by synaptic inputs are important for neural coding.In general,excitatory synaptic inputs facilitate the firing activities of neurons,and inhibitory synaptic inputs suppress the firing activities.In the present work,the autapse model with adjustable current decay speed is considered,and the suppression effects of excitatory autapse on neuronal firing responses are simulated near subcritical Hopf bifurcation in the Morris-Lecar(ML)neuron model,which are compared with the suppression effects of the inhibitory autapse.Furthermore,the dynamical mechanisms of the suppression effects are acquired with the help of the phase response curve and phase trajectories perturbed by excitatory autaptic current.Near the subcritical Hopf bifurcation,the ML neuron exhibits monostable periodic spiking and coexistence of periodic spiking and resting state.For monostable periodic spiking,excitatory autaptic current with fast and middle decay speeds can induce the periodic spiking with reduced firing frequency and the mixed-mode oscillations(MMOs)that are alternations between subthreshold oscillations and a spike,respectively,and inhibitory autaptic current with middle and slow decay speeds can also induce these two behaviors,respectively.For the periodic spiking in the coexistence region,besides the above two behaviors,excitatory autaptic current with middle decay speed and inhibitory autaptic current with slow decay speed can induce the change from spiking to resting state.The results enrich the paradoxical cases that excitatory inputs suppress the neuronal firing responses,and present the different nonlinear mechanisms in the suppression effects of excitatory and inhibitory self-feedbacks on the neuronal spiking,which provide novel measures to modulate neuronal firing activity.
作者
黎丽
赵志国
古华光
Li Li;Zhao Zhi-Guo;Gu Hua-Guang(Guangdong Key Laboratory of Modern Control Technology,Institute of Intelligent Manufacturing,Guangdong Academy of Sciences,Guangzhou 510070,China;Department of Science,Henan Institute of Technology,Xinxiang 453003,China;School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai 200092,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第5期73-87,共15页
Acta Physica Sinica
基金
国家自然科学基金(批准号:11802085,11872276,12072236)
广州市科技计划项目(批准号:202102021167)
广东省科学院建设国内一流研究机构行动专项(批准号:2021GDASYL-20210103088)
河南省科技攻关计划(批准号:212102310827)
河南省高等学校重点科研项目(批准号:21A110008)资助的课题.
