, Volume 3, Issue 5, pp 240–249 | Cite as

Discrimination among temporal patterns of stimulation in a computer model of a coelenterate nerve net

  • Lester G. Fehmi
  • Theodore H. Bullock


A simulation study is reported of the spread of excitation in a digital computer model based quite realistically on a coelenterate nerve net. The question posed is whether an elementary nervous system with randomly distributed properties can discriminate between time patterns of stimuli at the same average frequency. Forty-four temporal patterns of stimulation, each composed of seven stimuli in the same total period of time were applied to each of nine simulated nerve nets with each of eleven different distributions of four rates of decay of facilitation. The results may be summarized as follows:
  1. 1.

    The simulated nerve nets used were able reliably to discriminate between many of the time patterns used. The factors entering into range and acuity of pattern discrimination by the net are identified.

  2. 2.

    The simulated nerve nets tended to support a greater spread of excitation in response to even temporal distribution of stimuli than in response to clustered distributions of stimuli under certain conditions. These conditions are specified.

  3. 3.

    The response measure which was used (“final spread”) is shown to give different results in some cases than either of two other measures (“average” spread for the seven stimuli and “maximum spread”).

  4. 4.

    The simulated nerve nets were able to produce reliable differences in the spread of excitation between certain patterns and their temporally mirror-image counterparts. The necessary conditions for such pattern recognition are described.


The relationships among the principal variables, namely the temporal distribution of stimuli, the specific sequence of junction decay rates, the magnitudes of facilitation decay rates, and their relative frequency distributions are described as they affect the spread of excitation in the nerve net. The overall finding that the net is able to discriminate between some temporal patterns gathers significance in that it represents an ability of the net to translate temporally coded information into spatial form. Thus, it is shown that already at the level of a simplified model of a coelenterate nervous system, the requisites for temporal to spatial translation are met.


Temporal Distribution Decay Rate Temporal Pattern Response Measure Digital Computer 
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Copyright information

© Springer-Verlag 1967

Authors and Affiliations

  • Lester G. Fehmi
    • 1
    • 2
  • Theodore H. Bullock
    • 1
    • 2
  1. 1.Departments of Psychology and Zoology and Brain Research InstituteUniversity of CaliforniaLos Angeles
  2. 2.Department of NeurosciencesUniversity of CaliforniaSan Diego

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