Brain development, zebrafish

In the developing zebrafish brain the pineal complex (grey), consisting of a pineal and a small left-sided parapineal, is located right at the dorsal surface of the brain. The pineal gland produces the hormone melatonin, which plays a role in controlling sleep patterns. The axon tracts of the brain have been labelled for the cytoskeletal component tubulin (magenta) and synaptic neuropil (clusters of axons) are shown in cyan. Width of image is approximately 300 micrometres.