Some thoughts about neural coding and spike trains1

This communication introduces the topic. Foundations: Core concepts: Codings are relations summarized by rules or `codesʹ. Special codings are `neuralʹ, `naturalʹ (in everyday life), `experimentalʹ (in laboratories), `conditionalʹ (to partner restrictions), etc. Partial aspects are mechanisms, what partners say about each other, etc. Critical experimental issues: Trains are evaluated by when spikes occur: i.e. as point processes and timings. Trains and point process representations become synonyms. Any code must: (i) be a `number (rate) codʹ and an `interval codʹ; and (ii) include `referent, trainʹ covariations involving steady states with overall averages and fluctuations with patterns (dispersions, sequences). Seminal findings. Early data proved trains participated in codings; this is accepted unanimously. Inevitably, though accepted less readily, codings included rates, intervals, averages and patterns. Literature highlights. (1) Confirmed the seminal finding (2.2.) over vast domains; (2) Demonstrated both general and synaptic codings (referents, respectively, sensory, states, etc. and trains in directly connected neurons); (3) Revealed overlap between general and synaptic coding features. Overlap allows train participation in network dynamics; (4) Introduced natural formal contexts. (Point Process Mathematics, Communication. Information and Dynamical Systems Theories); (5) Includes confused opinions: (i) Opposition between rates and intervals; (ii) claims that averages are meaningful but patterns irrelevant. Both, overlooking foundations and evidence, are untenable.