Zebrafish embryo

A composition showing dorsal views of an undissected and dissected 4 days post fertilisation zebrafish brain. These embryos have been labelled with anti-acetylated tubulin antibody(green) that labels neuronal tracts and anti-SV2(magenta) that stains neuropil. Neuropil is a region between neuronal cell bodies in the gray matter of the brain and blood-brain barrier (i.e. the central nervous system). It consists of a dense tangle of axon terminals, dendrites and glial cell processes. It is where synaptic connections are formed between branches of axons and dendrites.