The study that found the robust networks is part of an ongoing research program led by Paul, who has been studying AgCC for several decades. AgCC occurs in approximately one of every 4000 live births. The typical corpus callosum comprises almost 200 million axonsthe connections between brain cellsand is the largest fiber bundle in the human brain. In AgCC, those fibers fail to cross the gap between the hemispheres during fetal development, forcing the two halves of the brain to communicate using more indirect and currently unknown means.
"In the 1960s and 1970s, Roger Sperry at Caltech studied 'split-brain' patients in whom the corpus callosum was surgically severed as a treatment for epilepsy," explains Paul. "Our research on AgCC has moved in a different direction and focuses on a naturally occurring brain malformation that occurs before birth. This allows us to examine how, and to what extent, the brain can compensate for the loss of the corpus callosum as a person grows to adulthood."
According to the team, the findings are especially valuable in light of current theories that link impaired brain connections with clinical conditions including autism and schizophrenia.
"We are now examining AgCC subjects who are also on the autism spectrum, in order to gain insights about the role of brain connectivity in autism, as well as in healthy social interactions," says Tyszka. "About a third of people with AgCC also have autism, and altered connectivity in the corpus callosum has been found in autism. The remarkable compensation in brain functional networks that we found here may thus have important implications also for understanding the function
|Contact: Deborah Williams-Hedges|
California Institute of Technology