中国物理B ›› 2014, Vol. 23 ›› Issue (2): 28701-028701.doi: 10.1088/1674-1056/23/2/028701

• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

Bifurcation diagram globally underpinning neuronal firing behaviors modified by SK conductance

陈梦娇a, 令恒莉a, 刘一辉a, 屈世显b, 任维a   

  1. a Key Laboratory of MOE for Modern Teaching Technology and College of Life Sciences, Shaanxi Normal University, Xi’an 710062, China;
    b Institute of Theoretical & Computational Physics, School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062, China
  • 收稿日期:2013-05-07 修回日期:2013-07-03 出版日期:2013-12-12 发布日期:2013-12-12
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 30900443) and the Fundamental Research Funds for the Central Universities, China (Grant Nos. GK201302052 and GK261001007).

Bifurcation diagram globally underpinning neuronal firing behaviors modified by SK conductance

Chen Meng-Jiao (陈梦娇)a, Ling Heng-Li (令恒莉)a, Liu Yi-Hui (刘一辉)a, Qu Shi-Xian (屈世显)b, Ren Wei (任维)a   

  1. a Key Laboratory of MOE for Modern Teaching Technology and College of Life Sciences, Shaanxi Normal University, Xi’an 710062, China;
    b Institute of Theoretical & Computational Physics, School of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062, China
  • Received:2013-05-07 Revised:2013-07-03 Online:2013-12-12 Published:2013-12-12
  • Contact: Qu Shi-Xian, Ren Wei E-mail:sxqu@snnu.edu.cn;renwei@snnu.edu.cn
  • About author:87.19.L-; 87.16.Vy; 87.19.ll; 05.45.-a
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 30900443) and the Fundamental Research Funds for the Central Universities, China (Grant Nos. GK201302052 and GK261001007).

摘要: Neurons in the brain utilize various firing trains to encode the input signals they have received. Firing behavior of one single neuron is thoroughly explained by using a bifurcation diagram from polarized resting to firing, and then to depolarized resting. This explanation provides an important theoretical principle for understanding neuronal biophysical behaviors. This paper reports the novel experimental and modeling results of the modification of such a bifurcation diagram by adjusting small conductance potassium (SK) channel. In experiments, changes in excitability and depolarization block in nucleus accumbens shell and medium-spiny projection neurons are explored by increasing the intensity of injected current and blocking the SK channels by apamin. A shift of bifurcation points is observed. Then, a Hodgkin–Huxley type model including the main electrophysiological processes of such neurons is developed to reproduce the experimental results. The reduction of SK channel conductance also shifts the bifurcations, which is in consistence with experiment. A global bifurcation paradigm of this shift is obtained by adjusting two parameters, intensity of injected current and SK channel conductance. This work reveals the dynamics underpinning modulation of neuronal firing behaviors by biologically important ionic conductance. The results indicate that small ionic conductance other than that responsible for spike generation can modify bifurcation points and shift the bifurcation diagram and, thus, change neuronal excitability and adaptation.

关键词: neuron, Hopf bifurcation, SK channel, excitability

Abstract: Neurons in the brain utilize various firing trains to encode the input signals they have received. Firing behavior of one single neuron is thoroughly explained by using a bifurcation diagram from polarized resting to firing, and then to depolarized resting. This explanation provides an important theoretical principle for understanding neuronal biophysical behaviors. This paper reports the novel experimental and modeling results of the modification of such a bifurcation diagram by adjusting small conductance potassium (SK) channel. In experiments, changes in excitability and depolarization block in nucleus accumbens shell and medium-spiny projection neurons are explored by increasing the intensity of injected current and blocking the SK channels by apamin. A shift of bifurcation points is observed. Then, a Hodgkin–Huxley type model including the main electrophysiological processes of such neurons is developed to reproduce the experimental results. The reduction of SK channel conductance also shifts the bifurcations, which is in consistence with experiment. A global bifurcation paradigm of this shift is obtained by adjusting two parameters, intensity of injected current and SK channel conductance. This work reveals the dynamics underpinning modulation of neuronal firing behaviors by biologically important ionic conductance. The results indicate that small ionic conductance other than that responsible for spike generation can modify bifurcation points and shift the bifurcation diagram and, thus, change neuronal excitability and adaptation.

Key words: neuron, Hopf bifurcation, SK channel, excitability

中图分类号:  (Neuroscience)

  • 87.19.L-
87.16.Vy (Ion channels) 87.19.ll (Models of single neurons and networks) 05.45.-a (Nonlinear dynamics and chaos)