from WIRED

Scientists Watch a Memory Form in a Living Brain

While observing fearful memories take shape in the brains of fish, neuroscientists saw an unexpected level of synaptic rewiring.

by YASEMIN SAPLAKOGLU

( originally published in Quanta Magazine)

Zebrafish Brain
The brain of this zebra fish larva glows with fluorescent markers that illuminate its neural activity. PHOTOGRAPH: ANDREY ANDREEV/THAI TRUONG/SCOTT FRASER; TRANSLATIONAL IMAGING CENTER/USC

IMAGINE THAT WHILE you are enjoying your morning bowl of Cheerios, a spider drops from the ceiling and plops into the milk. Years later, you still can’t get near a bowl of cereal without feeling overcome with disgust.

Researchers have now directly observed what happens inside a brain learning that kind of emotionally charged response. In a new study published in January in the Proceedings of the National Academy of Sciences, a team at the University of Southern California was able to visualize memories forming in the brains of laboratory fish, imaging them under the microscope as they bloomed in beautiful fluorescent greens. From earlier work, they had expected the brain to encode the memory by slightly tweaking its neural architecture. Instead, the researchers were surprised to find a major overhaul in the connections.

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