Circuitry and Beyond: How Far Does Connectivity Get Us?
The prevailing view of organized neural masses is in the terms and imagery of circuits and networks, including “local circuits.” Reasons are given for doubting the adequacy of thinking in terms of circuitry. Using the analogy of a crowd at a sports stadium, I underline those features of neural function that involve several kinds of signals, for example communication by other than conventional synapses, including electrical field effects and transmitter and modulator action over distances of more than a cleft width. Nonsynaptic variables that contribute to integration and do not fit in the usual view of circuitry include the roles of geometry of axonal terminal ramifications and dendritic arbors and the three-dimensional distribution of anatomical synapses to form functional synapses. It is a major challenge today to avoid confining our mental image and dialogue to the schematics and the seriously simplified list of parameters in circuit and network diagrams, though they are essential first steps in understanding any given neural system.
KeywordsCentral Pattern Generator Coupling Function Dendritic Arbor Local Circuit Electrical Field Effect
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