Khaberni - A recent scientific study showed that adolescent brains do not just eliminate excess neural connections, as previously believed, but also establish new and dense foci of neural synapses during this life stage, which may play a pivotal role in the development of higher mental abilities and lifelong thinking formation.
According to the study, conducted by researchers from Kyushu University in Japan and published in the journal Science Advances, these "synaptic foci" appear exclusively during adolescence, in specific areas of the neuronal cells, challenging the prevailing theory that brain development in this stage is associated only with "neural pruning"—the removal of weak or unused connections.
Adolescence is a critical period in brain development, as advanced cognitive abilities such as planning, decision-making, and abstract thinking continue to mature. Despite this, scientists still lack a full understanding of the mechanisms that reshape the neural networks during this sensitive phase.
Professor Takeshi Imai from the School of Medical Sciences at Kyushu University explained that his team originally aimed not to study mental disorders but was exploring the structure of the cerebral cortex using high-resolution imaging tools. He added, "We were surprised to discover a previously unknown region with a high density of dendritic spines, which are the structures where excitatory neural synapses form."
The researchers focused on neuronal cells located in the fifth layer of the cerebral cortex, which are central points for the gathering and output of neural information, thus playing a central role in regulating the processing of information within the brain. Using advanced techniques for tissue clearing and ultra-high-resolution imaging, the team was able to map out the complete distribution of neural synapses on these cells.
The results showed that these dense foci of synapses are not present in early childhood stages but begin to form during adolescence. In young mice aged two weeks, the synapses were relatively evenly distributed, but between the ages of three and eight weeks—a period corresponding to late childhood and adolescence—the density of synapses increased sharply in a specific area of the dendrites, forming a "hotspot" for neural synapse formation.
Imai said that these findings "suggest that the neural pruning hypothesis during adolescence needs to be revisited," clarifying that building new synapses may be just as important as removing old ones.
