Marmosets are stars of Japan’s ambitious brain project

Unlike its Western counter­parts, Japan’s effort will be based on a rare resource — a large population of marmosets that its scientists have developed over the past decade — and on new genetic techniques that might be used to modify these highly social animals. The goal of the ten-year Brain/MINDS (Brain Mapping by Integrated Neurotechnologies for Disease Studies) project is to map the primate brain to accelerate understanding of human disorders such as Alzheimer’s disease and schizo­phrenia. On 11 September, the Japanese science ministry announced the names of the group leaders — and how the project would be organized. Funded at ¥3 billion (US$27 million) for the first year, probably rising to about ¥4 billion for the second, Brain/MINDS is a fraction of the size of the European Union’s Human Brain Project and the United States’ BRAIN (Brain Research through Advancing Innovative Neurotechnologies) Initiative, both of which are projected to receive at least US$1 billion over the next decade. But researchers involved in those efforts say that Brain/MINDS fills a crucial gap between disease models in smaller animals that too often fail to mimic human brain disorders, and models of the human brain that need validating data. “It is essential that we have a genetic primate model to study cognition and cognitive brain disorders such as schizophrenia and depression, for which we do not have good mouse models,” says neuroscientist Terry Sejnowski at the Salk Institute in La Jolla, California, who is a member of the National Institutes of Health BRAIN Initiative Working Group. “Other groups in the United States and China have started transgenic-primate projects, but none is as large or as well organized as the Japanese effort.” Neuroscientist Henry Markram at the Swiss Federal Institute of Technology in Lausanne, who heads the European initiative, also welcomes the effort: “It is absolutely impressive, and Japan should be applauded for putting together an incredible plan.” Central to the Brain/MINDS effort is the creation of transgenic marmosets to elucidate cognitive function and as models of human brain disease. Although more distantly related to humans than primates such as chimpanzees, these monkeys are in many ways ideal for brain research. Their small size and fecundity make them easier and more efficient to work with than, say, macaques, which are commonly used as animal models. The marmoset brain is compact, too — just 8 grams, making it relatively easy to analyse. Yet the frontal lobe — a brain area involved in human psychiatric disease — is more developed in marmosets and more like the human version than the frontal lobes of other animals with similarly small brains. Marmosets also share behavioural characteristics with humans that other monkeys, and even chimps, do not, such as living in family units that resemble human ones and making eye contact as a means of communication, rather than as a form of aggression. The monkeys are thus expected to be a good model for studying conditions such as Parkinson’s disease and Alzheimer’s disease. And learning what causes the breakdown of social behaviours such as making eye contact might help to clarify the mechanisms underlying autism, suggests.  Nature  Original web page at Nature