A Quantum-Classical Model of Brain Dynamics

In this article, we posit an approach to study brain processesnby means of the quantum-classical dynamics of a Mixed Weyl symbol. The Mixed Weyl symbol is used to describe brain processes at the microscopic level and, when averaged over an appropriate ensemble, provides a link to the results of measurements made at the mesoscopic scale. The approach incorporates features of three well-known approaches (which are also reviewed in this paper), namely the electromagnetic field theory of the brain, orchestrated objective reduction theory, and the dissipative quantum model of the brain. Within this approach, quantum variables (such as nuclear and electron spins, dipolar particles, electron excited states, and tunnelling degrees of freedom) may be represented by spinors while the electromagnetic fields and phonon modes involved in the processes are treated either classically or semiclassicaly, by also considering quantum zero-point fluctuations. In the proposed computation scheme, zero-point quantum effects can be incorporated into numerical simulations by controlling the temperature of each field mode via coupling to a dedicated Nosè-Hoover chain thermostat. The temperature of each thermostat is chosen in order to reproduce quantum statistics in the canonical ensemble. Viewing the brain in terms of QC processes has consequences on the theory of clinical psychology and potential implications for its practice.