Non-Critical String Theory Formulation of Microtubule Dynamics and Quantum Aspects of Brain Function

Abstract

Microtubule (MT) networks, subneural paracrystalline cytosceletal structures, seem to play a fundamental role in the neurons. We cast here the complicated MT dynamics in the form of a $1+1$-dimensional non-critical string theory, thus enabling us to provide a consistent quantum treatment of MTs, including enviromental {\em friction} effects. We suggest, thus, that the MTs are the microsites, in the brain, for the emergence of stable, macroscopic quantum coherent states, identifiable with the {\em preconscious states}. Quantum space-time effects, as described by non-critical string theory, trigger then an {\em organized collapse} of the coherent states down to a specific or {\em conscious state}. The whole process we estimate to take ${\cal O}(1\,{\rm sec})$, in excellent agreement with a plethora of experimental/observational findings. The {\em microscopic arrow of time}, endemic in non-critical string theory, and apparent here in the self-collapse process, provides a satisfactory and simple resolution to the age-old problem of how the, central to our feelings of awareness, sensation of the progression of time is generated.