A Non - Critical String ( Liouville ) Approach to Brain Microtubules : State Vector Reduction , Memory Coding and Capacity

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 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 preconscious states. Quantum space-time effects, as described by non-critical string theory, trigger then an organized collapse of the coherent states down to a specific or conscious state. The whole process we estimate to take O(1 sec), in excellent agreement with a plethora of experimental/observational findings. The 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. In addition, the complete integrability of the stringy model for MT we advocate in this work proves sufficient in providing a satisfactory solution to memory coding and capacity. Such features might turn out to be important for a model of the brain as a quantum computer.