THE DEVELOPMENT OF INDIVIDUALITY HAS A NEUROBIOLOGICAL FOUNDATION
News Editor: Tina Pentland
A startling new study, using an animal model to investigate brain plasticity as a measure of individual difference, has found that the adult brains of mice have the capacity to develop new cells as a result of differences in behaviour and experience, which lead to differences in brain development. Hence, for the first time, a link between behaviour, experience, brain structure, and the development of individuality has been demonstrated. The interdisciplinary study, published in Science on 10 May 2013, saw the collaboration of neuroscientists, ethologists, computer scientists and developmental psychologists in research institutions across Germany, including the Centre for Neurodegenerative Diseases – Cluster of Excellence at the TU Dresden, the Max Planck Institute for Human Development in Berlin, and the Research Centre for Artificial Intelligence in Saarbrücken. Using an animal model of 40 genetically identical mice, the study collected data on their movements (or “roaming entropy”) with the aim of finding some answers to the questions how or why individuality develops, such as has been observed previously in identical twins. The finding – that brains are capable of neurogenesis – suggests there is a neurobiological foundation for individuality that also applies to humans.
Biologist Julia Freund and computer scientist Dr. Andreas Brandmaier, who are the lead authors of the study, developed the mouse model specifically to examine the environmental influences on genetically identical animals and their effects on behavioural and neural development. The study was conducted over a 3-month period and the mice were kept in cages according to experimental condition: an enriched group (enhanced environment, ENR), a control group (standard cage conditions, CTR), and a baseline. The 40 mice which made up the ENR group were fitted with transponders and housed in a special enclosure containing antennae at various locations to track their movements, according to a measure called “roaming entropy”. Each contact was recorded as a “unique event”. Importantly, hippocampal neurogenesis correlated positively with the number of unique events recorded, not just movement or general activity. Hence, by the end of the study, each mouse differed according to its particular interactions with the environment, which was constant.
The study is significant for two main reasons: first, it has successfully developed a model for identifying mechanisms of brain plasticity and individual differences and, second, it has shown that these differences should be attributed to the individual’s differential behaviour and “nonshared” interactions with the environment, which is strongly suggestive of a neurobiological foundation in the development of individuality.
The Center for Regenerative Therapies Dresden – CRTD at the Technische Universität Dresden was established in 2006 and was able to assert itself in the third round of the German excellence initiative as an excellence cluster and DFG Research Center. It is directed by the developmental and neurobiologist Prof. Dr. Michael Brand. The aim of the CRTD is to study the body’s self-healing capabilites and develop completely new regenerative therapies for previously incurable diseases. The Center’s research topics focus on haematology and immunology, diabetes, neurodegenerative diseases, and bone replacement. Currently four professors and nine research group leaders work at the CRTD and are integrated in an interdisciplinary network of more than 90 members of seven different institutions in Dresden. The network is additionally supported by 18 corporate partners. Synergies within the network allow a rapid transfer of findings from basic science to clinical applications.