Cutting Connections

The vast number and complexity of connections between human brain cells is staggering, and yet the brain’s ability to process information is surprisingly efficient. That’s in part because as a child grows and learns new things, certain connections are made stronger while others are eliminated – a process called pruning. Around adolescence a good deal of pruning occurs, which is thought to optimise processing power, but new research suggests, that over-zealous pruning may increase a person’s risk for schizophrenia – a condition that incidentally manifests at adolescence or early adulthood. The brains of patients with schizophrenia were found to have higher levels of a protein called C4 (green) – pictured here at connections between human neurons. While C4 is better known for its role outside the brain as an immune factor targeting pathogens for elimination, inside the brain it seems undesirable neural connections are C4’s targets.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image courtesy of Heather de Rivera, the McCarroll lab
• Department of Genetics, Harvard Medical School, Boston, USA
• Image copyright held by original authors
• Research published in Nature, January 2016