Journal of Computational Neuroscience

, Volume 19, Issue 1, pp 39–51 | Cite as

Fractal Stochastic Modeling of Spiking Activity in Suprachiasmatic Nucleus Neurons

  • Sung-IL Kim
  • Jaeseung Jeong
  • Yongho Kwak
  • Yang In Kim
  • Seung Hun Jung
  • Kyoung J. Lee


Individual neurons in the suprachiasmatic nucleus (SCN), the master biological clock in mammals, autonomously produce highly complex patterns of spikes. We have shown that most (~90%) SCN neurons exhibit truly stochastic interspike interval (ISI) patterns. The aim of this study was to understand the stochastic nature of the firing patterns in SCN neurons by analyzing the ISI sequences of 150 SCN neurons in hypothalamic slices. Fractal analysis, using the periodogram, Fano factor, and Allan factor, revealed the presence of a 1/f-type power-law (fractal) behavior in the ISI sequences. This fractal nature was persistent after the application of the GABAA receptor antagonist bicuculline, suggesting that the fractal stochastic activity is an intrinsic property of individual SCN neurons. Based on these physiological findings, we developed a computational model for the stochastic SCN neurons to find that their stochastic spiking activity was best described by a gamma point process whose mean firing rate was modulated by a fractal binomial noise. Taken together, we suggest that SCN neurons generate temporal spiking patterns using the fractal stochastic point process.


suprachiasmatic nucleus interspike intervals fractal stochastic gamma point processes long-term correlations 


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Copyright information

© Springer Science + Business Media, Inc. 2005

Authors and Affiliations

  • Sung-IL Kim
    • 1
  • Jaeseung Jeong
    • 1
  • Yongho Kwak
    • 1
  • Yang In Kim
    • 2
  • Seung Hun Jung
    • 2
  • Kyoung J. Lee
    • 3
  1. 1.National Creative Research Initiative Center for Neurodynamics and Department of PhysicsKorea UniversitySeoulSouth Korea
  2. 2.Department of Physiology and Neuroscience Research InstituteKorea University College of MedicineSeoulSouth Korea
  3. 3.National Creative Research Initiative Center for Neurodynamics and Department of PhysicsKorea UniversitySeoulSouth Korea

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