Calcium dynamics in the mouse hippocampus show silent neurons (in blue) alongside highly active neurons (in yellow and red) that synchronize their activity in response to foot-shock conditioning.

Hippocampal neuron activity coalesces into a coordinated firing pattern as memories form in the mouse brain, according to a study published on January 15 in The FASEB Journal. The authors used fear conditioning to produce “activity synchronization” in neurons that was correlated with freezing behavior, a process they believe “is critical for trace memory formation and retrieval,” they write in their study.

“There are tens of millions of neurons in the hippocampus but only a small fraction of them are involved in this learning process,” says University of New Hampshire neurobiologist and coauthor Xuanmao Chen in a press release. “Before engaging in Pavlovian conditioning, these neurons are highly active, almost chaotic, without much coordination with...

Y. Zhou et al., “Induction of activity synchronization among primed hippocampal neurons out of random dynamics is key for trace memory formation and retrieval,” The FASEB Journal, doi:10.1096/fj.201902274R, 2020.

Amy Schleunes is an intern at The Scientist. Email her at

Interested in reading more?

The Scientist ARCHIVES

Become a Member of

Receive full access to more than 35 years of archives, as well as TS Digest, digital editions of The Scientist, feature stories, and much more!
Already a member?