  We propose a new model of neural network. It consists of spin variables to
describe the state of neurons as in the Hopfield model and new gauge variables
to describe the state of synapses. The model possesses local gauge symmetry and
resembles lattice gauge theory of high-energy physics. Time dependence of
synapses describes the process of learning. The mean field theory predicts a
new phase corresponding to confinement phase, in which brain loses ablility of
learning and memory.
