Traumatic memories can alter the brain connections

The research team used longitudinal two-photon imaging and various computational neuroscience techniques to determine how neural activity changes in the mouse prefrontal cortex after learning in a fear-conditioning paradigm. Prefrontal neurons behave in a highly complex manner, and each neuron responds to various sensory and motor events.

Importantly, the researchers uncovered direct evidence that associative memory formation was accompanied by a novel associative connection between originally distinct networks, i.e., the conditioned stimulus (CS, e.g., tone) network and the unconditioned stimulus (US, e.g., fearful experience) network.

"We successfully detected a neural population that encodes fear memory," says Agetsuma. "Our analyses showed us that fear conditioning induced the formation of a fear-memory neural network with 'hub' neurons that functionally connected the memory neurons."

Reference: Masakazu Agetsuma, Issei Sato, Yasuhiro R. Tanaka, Luis Carrillo-Reid, Atsushi Kasai, Atsushi Noritake, Yoshiyuki Arai, Miki Yoshitomo, Takashi Inagaki, Hiroshi Yukawa, Hitoshi Hashimoto, Junichi Nabekura, Takeharu Nagai. Activity-dependent organization of prefrontal hub-networks for associative learning and signal transformation. Nature Communications, 2023; 14 (1) DOI: 10.1038/s41467-023-41547-5