Dorsal view of zebrafish brain (4 day-post fertilization)

An image of zebrafish brain neuronal development at 4 days post-fertilization. Three components of the neural network are seen in this image. Neuropil, or dense areas of interwoven neuron dendrites and axons, are shown in magenta and are clearly detectable in structures such as the eyes. Axon tracks are shown in green. A specific subtype of neurons called GABA-ergic cells, which use the inhibitory neurotransmitter GABA, are seen in cyan.