  In the sensation of tones, visions and other stimuli, the "surround
inhibition mechanism" (or "lateral inhibition mechanism") is crucial. The
mechanism enhances the signals of the strongest tone, color and other stimuli,
by reducing and inhibiting the surrounding signals, since the latter signals
are less important. This surround inhibition mechanism is well studied in the
physiology of sensor systems. The neural network with two hidden layers in
addition to input and output layers is constructed; having 60 neurons (units)
in each of the four layers. The label (correct answer) is prepared from an
input signal by applying seven times operations of the "Hartline mechanism",
that is, by sending inhibitory signals from the neighboring neurons and
amplifying all the signals afterwards. The implication obtained by the deep
learning of this neural network is compared with the standard physiological
understanding of the surround inhibition mechanism.
