Birds Brainier Than Previously Thought
The brains of birds appear to be more similar to those of mammals than previously thought. An international consortium, funded in part by the National Institutes of Health (NIH), this week announced new language to identify brain structures in birds. This landmark change, the first such shift in a century, reflects new evidence about the function and evolution of the vertebrate brain, mapping out similarities between structures and cognitive abilities in avian brains and the brains of mammals. The Consortium report is published in the February 2005 issue of Nature Reviews Neuroscience.
The new research revises the work of 19th century comparative neurobiologist Ludwig Edinger, who first named avian brain structures using the classical view of evolution and the ideas of Charles Darwin. Edinger believed that evolution was progressive and linear; that the mammalian brain was a more evolved form of the rudimentary structures of the reptilian and avian brain. New findings over the years have shown that birds possess neural capacities beyond those of some small mammal species.
The old terminology for areas of the bird brain equated them to human basal ganglia — structures thought to be involved in only the most instinctive behavior. Previous opinion held that the malleable behavior of mammals required the higher-order neocortex found in mammals. But collected genetic, behavioral, and molecular evidence shows that, although the structures are organized differently, areas of the avian brain perform functions similar to those of the mammalian neocortex, which is responsible for performing sensory information processing.
In addition to subdividing regions of the brain, the new taxonomy erases misnomers stemming from the incorrect use of prefixes to imply the relative age of different regions. The clarity of the new labels allows neuroscientists studying non-avian brains to understand the relevance of findings in bird research.
“This new approach to the anatomy of the avian brain allows scientists working with birds and mammals to compare their findings more effectively,” said Thomas R. Insel, M.D., director of the National Institute of Mental Health, lead institute on this project. “This re-naming effort should also increase the power of comparative studies, yielding new insights from the avian brain that can help us to understand other vertebrates, including humans.”
The Avian Brain Nomenclature Consortium comprised a team of 28 neuroscientists — international specialists in avian, mammalian, reptilian, and fish neurobiology — led by Duke University neurobiologist Erich Jarvis. The project was funded through the National Science Foundation and several NIH institutes: National Institute of Mental Health, National Institute of Neurological Disorders and Stroke, the National Institute on Deafness and Other Communication Disorders, and the National Institute on Drug Abuse.
International co-authors included:
Onur Güntürkün, Ruhr-UniversitÃ¤t Bochum, Germany; András Csillag, Semmelweis University, Hungary; Loreta Medina, University of Murcia, Spain; George Paxinos, Prince of Wales Medical Research Institute, Australia; Martin Wild, University of Auckland, New Zealand; Tom Smulders, University of Newcastle, United Kingdom
Co-authors from Duke University Medical Center included:
Lubica Kubikova, Connie Siang, Kazuhiro Wada, and Jing Yu
Co-authors from other U.S. universities included:
Wayne Kuenzel, University Arkansas; Diane Lee, California State University Long Beach; Stephanie White, University of California, Los Angeles; Harvey Karten, University of California, San Diego; Georg Striedter, University of California at Irvine; Jennifer Dugas-Ford, University of Chicago; Laura Bruce, Creighton University School of Medicine; Ann Butler, George Mason University; Gregory F. Ball, Johns Hopkins University; Sarah Durand, LaGuardia–CUNY; Claudio Mello, Oregon Health & Science University; Gerald Hough, Rowan University; Toru Shimizu, University of South Florida; Scott Husband, University of South Florida; Alice Powers, St. John's University; Keiko Yamamoto, University of Tennessee Health Science Center; Anton Reiner, University of Tennessee Health Science Center; David J. Perkel, University of Washington
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