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Nonlinear oscillations, noise and chaos in neural delayed feedback.

机译:神经延迟反馈中的非线性振荡,噪声和混沌。

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摘要

Bifurcations and complex oscillations in the human pupil light reflex (PLR) are studied. Autonomous pupil area oscillations are produced by substituting electronically controllable nonlinear feedback for the normal negative feedback of this reflex. A physiologically sound theoretical framework in which to study pupillary oscillations is developed. The model, framed as a delay-differential equation (DDE), agrees quantitatively with the simpler periodic behaviors and qualitatively with the complex behaviors. Much of the aperiodicity in the data can be ascribed to noise and transients rather than to chaos. The critical behavior of the PLR at oscillation onset is different with piecewise constant rather than smooth negative feedback. In the former, relative fluctuations in period are larger than those in amplitude, and vice versa in the latter. Properties of the time solutions and densities of a stochastic DDE are used to explain this experimental result. The Hopf bifurcation in this system is postponed by both additive and multiplicative colored noise. Theoretical insight into the behavior of stationary densities of DDE's and the origin of the postponement is given, and implications for analyzing bifurcations in neural delayed feedback systems are discussed.
机译:研究了人类瞳孔光反射(PLR)中的分叉和复杂振荡。通过用电子可控制的非线性反馈代替该反射的正常负反馈,可以产生自主的瞳孔面积振荡。一个生理学上合理的理论框架,在其中研究瞳孔振荡。该模型以延迟微分方程(DDE)为框架,在数量上与更简单的周期性行为相吻合,在质量上与复杂的行为相吻合。数据中的许多非周期性可以归因于噪声和瞬变,而不是混沌。 PLR在振荡开始时的临界行为与分段常数不同,而不是平滑的负反馈。在前者中,周期的相对波动大于振幅,而在后者中则相反。时间解的性质和随机DDE的密度用于解释该实验结果。该系统中的Hopf分叉被加性和乘性有色噪声延迟。从理论上了解了DDE的静态密度的行为以及延迟的起源,并讨论了在神经延迟反馈系统中分析分叉的意义。

著录项

  • 作者

    Longtin, Andre.;

  • 作者单位

    McGill University (Canada).;

  • 授予单位 McGill University (Canada).;
  • 学科 Optics.
  • 学位 Ph.D.
  • 年度 1989
  • 页码 292 p.
  • 总页数 292
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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