Z SocialBiol. Struct. 1981 4, 211-224 Towards a unified brain theory Lester lngber Physical Studies Institute, Inc., P.O. Box W; Solana Beach, CA 92075, USA and Institute for Pure and Applied Physical Sciences, University of California San Diego, La Jolla, CA 92093, USA An approach to collective aspects of the neocortical system is formulated by methods of modern non-equilibrium statistical mechanics. Microscopic neuronal synaptic interactions are first spatially averaged over columnar domains. These spatially ordered domains include well formulated fluctuations that retain contact with the original physical synaptic parameters. They also are a suitable substrate for macroscopic spatial-temporal regions described by Fokker-Planck and Lagrangian formalisms. This development clarifies similarities and differences among previous studies, suggests new analytically supported insights into neocortical function and permits future approximation or elaboration within current paradigms of collective systems. I. Introduction and rationale Relative to other biological entities, the intrinsic synaptic activity of the most highly evolved mammalian human neocortex functions via the most degenerate and the shortest-ranged neuronal interactions. This suggests that many collective aspects of this system may be fruitfully studied similarly to other collective physical systems. I.e. collective effects from clustering of neurons (Szent~gothai & Arbib, 1974) or from statistical interactions (Katchalsky, Rowland & Blumenthal, 1974) are proposed to be mechanisms of information processing, in addition to the 'hard-wiring' mechanisms also possessed by other more ordered cortical entities (Afifi & Bergman, 1980; Sommerhoff, 1974). An approach has been recently formulated for this purpose (ingber, in preparation). Three major divisions of this work, corresponding to Sections IIIA, B and C respectively, will be referred to as SMNI-I, -II, -III, respectively. The preliminary results of this formulation recommend further detailed study of neocortical interactions using this methodology. Insights are gained into neocortical function at several scales of interaction, applicable to other related disciplines as discussed in Sections II and IV. In this sense, the possibility of a 'unified brain theory' is suggested. Reasonable criteria for any physical approach should include at least three basic Features in common with other collective physical systems. (A) Interactions Short-ranged neuronal interactions over time periods of several milliseconds should be derived from even more microscopic synaptic activites (Shepherd, 1977) [see Fig. l(a)]. 0140-1750/81/030211+14 $02.00/0 © 1981 Academic Press Inc. (London) Limited