Spontaneous changes in brain state influence the readiness to form memories, neuroscientists find - Medical Xpress

What the report says

Medical Xpress reported on July 24, 2026, that neuroscientists at the University of Tübingen have found evidence that spontaneous shifts in the brain’s internal state can affect how prepared the memory system is to encode new information. The work, led by Professor Andrea Burgalossi at the Institute of Neurobiology and the Werner Reichardt Center for Integrative Neuroscience, was published in Nature Communications.

The study examined mice and focused on the hippocampus, a brain region central to episodic memory. Researchers monitored place cells, neurons that become active in patterns linked to specific environments, while also tracking signs of internal brain state. According to the report, pupil size was used as an indicator of alertness or arousal, and changes in that state were associated with different activity among memory-related neurons, even when the animals were resting.

Medical Xpress said the team also observed changes in theta oscillations, brain rhythms associated with memory encoding. The researchers then tested whether these internal-state shifts might mark moments of heightened plasticity, when neural circuits are more capable of changing. By stimulating individual memory-related neurons during such periods, they were able to trigger new place-specific activity patterns, described in the report as the creation of new “memory cells” within the network.

The findings matter because they suggest memory formation may depend not only on external events but also on brief internal windows when the hippocampus is especially ready to reorganize. While the study was conducted in mice, the broader context is that mammalian hippocampal systems, including those in humans, are essential for forming episodic memories. The research may help scientists study how experiences become physically encoded in the brain.