Researchers from Kyushu University discovered a previously unrecognized synaptic “hotspot” that forms during adolescence, challenging the long-held view that adolescent brain development was dominated by synaptic pruning. This hotspot fails to form in mice carrying a schizophrenia-associated gene, pointing to a potential link between adolescent synaptic formation and psychiatric disorders, including schizophrenia.

Adolescence marks an important transition not just socially and physically, but neurologically. During this period, higher cognitive functions such as planning, problem-solving, and decision-making gradually mature. Yet, the underlying mechanisms of neural circuit development remain poorly understood.

Key to this process are synapses—the functional connections between neurons allow information to flow through the brain. Previously, it has long been hypothesized that synapse numbers increase during childhood and then decrease during adolescence. It has also been proposed that excessive “synaptic pruning,” a process that refines neural circuits by eliminating unused or weak connections, may lead to neuropsychiatric disorders. One example is schizophrenia, a condition characterized by hallucinations, delusions, or disorganized thinking.