February 6, 2014. The brain forms its thicket of connections early in life, but additions to its wiring diagram may be made even in adults, according to a study published in Neuron on January 8. The researchers, led by Christoph Kellendonk of Columbia University in New York City, suggest that too many of these extra connections may contribute to schizophrenia.
The study focused on a mouse model of schizophrenia developed by Kellendonk and colleagues that mimics the surplus of dopamine, a chemical messenger, found in the disorder. This extra dopamine is found mainly in a part of the basal ganglia, a region deep within the brain important for movement, learning, and motivation. These mice have problems with learning and motivation, similar to the cognitive and negative symptoms of schizophrenia.
In the new study, first author Maxime Cazorla and colleagues found that the brains of these mice had extra connections between neurons that aren’t normally connected. These “crossed wires” scrambled the activity in these neurons, leading to unexpected effects on movement. The wayward connections could be unplugged in several ways, however. For example, blocking dopamine receptors with haloperidol, an antipsychotic drug, decreased the number of connections. This points to a lasting plasticity in the adult brain, which future therapies for schizophrenia may take advantage of. (For more details, see the related news story.)—Michele Solis.