  We investigate the theory of observers in the quantum mechanical world by
using a novel model of the human brain which incorporates the glial network
into the Hopfield model of the neural network. Our model is based on a
microscopic construction of a quantum Hamiltonian of the synaptic junctions.
Using the Eguchi-Kawai large N reduction, we show that, when the number of
neurons and astrocytes is exponentially large, the degrees of freedom of the
dynamics of the neural and glial networks can be completely removed and,
consequently, that the retention time of the superposition of the wave
functions in the brain is as long as that of the microscopic quantum system of
pre-synaptics sites. Based on this model, the classical information entropy of
the neural-glial network is introduced. Using this quantity, we propose a
criterion for the brain to be a quantum mechanical observer.
