New nomenclature reflects similarities between bird and mammal brains.
Neuroscientists are revamping a naming system for birds' brains that has been in use for more than a century.
The old terminology hinders communication between bird neuroscientists and their mammalian counterparts, avian specialists say, because it does not reflect modern understanding.
The problem dates back to Ludwig Edinger, a German neuroscientist working in the nineteenth century. Edinger thought the cerebrum of the bird brain was primitive and consisted of nothing more than basal ganglia that control instinctive behaviour. In contrast, he thought, the mammalian brain consisted of layers that create a ‘neocortex’ and control learning.
Neuroscientists have known for decades that such a distinction is artificial. Signalling molecules and neurotransmitters operate similarly in the brains of birds and mammals. And researchers agree that birds can learn: crows can pass on tool-making skills, for example.
But the different terminology meant “the value of avian research was not coming across to mammalian researchers”, says Anton Reiner, a neuroscientist at the University of Tennessee Health Science Center at Memphis.
So a new system has been designed by the Avian Brain Nomenclature Consortium, a group of 29 specialists in bird, fish, reptile and mammalian brains, who first met at Duke University in Durham, North Carolina, in July 2002.
The meeting led to a naming system that illuminates the parallels between bird and mammalian brains. A technical paper describing the terminology was published last May in the Journal of Comparative Neurology (A. Reiner et al. 473, 377–414; 2004). It was quickly adopted by “the entire avian community”, says Erich Jarvis, a neuroscientist at Duke University who hosted the meeting. This month's Nature Reviews Neuroscience (E. Jarvis et al. 6, 151–159; 2005) carries a general introduction to the system for the wider community.
Stephanie White, a neuroscientist at the University of California, Los Angeles, says the terminology helps her to compare vocal learning behaviour in birds and mammals. “I don't even refer to the old nomenclature anymore,” she says.
But some argue that the terminology does not go far enough. A nomenclature “that is in greater harmony with mammalian terms and concepts”, remains possible, says George Paxinos, a neuroscientist at the Prince of Wales Medical Research Institute in Randwick, Australia. Until then, however, he says that he is grateful for the work the consortium has done to “get us out of the mess we were in”.