The 5-HT1A receptor is the most widespread serotonin receptor type and is involved in various functions like depression, schizophrenia, Alzheimer’s disease, and eating disorders. Our knowledge about the distribution of 5-HT1A receptors in birds is extremely limited. Therefore, a team of neuroanatomists and biopsychologists from the universities of Düsseldorf and Bochum analyzed the distribution of 5-HT1A receptor binding sites in the pigeon brain using quantitative in vitro receptor autoradiography with the selective radioligand [3H]-8-Hydroxy-2-(di-n-propylamino)tetralin ([3H]-8-OH-DPAT). What they discovered is a completely new landscape of neural subdivisions that hints to functional specializations that were unknown before. The picture of the entopallium shown here is a nice example for this new landscape that testifies the existence of new subdivisions. In addition, the regional pattern of distribution of 5-HT1A receptors displays a scattering similar to brain structures of mammals, furthering the discussion on the comparison of the avian and the mammalian brain.

Herold, C., Palomero-Gallagher, N., Güntürkün, O., Zilles, K. (2012). Serotonin 5-HT1A receptor binding sites in the brain of the pigeon (Columba livia). Neuroscience, 200, 1-12.