  We introduce here a fully automated convolutional neural network-based method
for brain image processing to Detect Neurons in different brain Regions during
Development (DeNeRD). Our method takes a developing mouse brain as input and i)
registers the brain sections against a developing mouse reference atlas, ii)
detects various types of neurons, and iii) quantifies the neural density in
many unique brain regions at different postnatal (P) time points. Our method is
invariant to the shape, size and expression of neurons and by using DeNeRD, we
compare the brain-wide neural density of all GABAergic neurons in developing
brains of ages P4, P14 and P56. We discover and report 6 different clusters of
regions in the mouse brain in which GABAergic neurons develop in a differential
manner from early age (P4) to adulthood (P56). These clusters reveal key steps
of GABAergic cell development that seem to track with the functional
development of diverse brain regions as the mouse transitions from a passive
receiver of sensory information (<P14) to an active seeker (>P14).
