Overview
- RIKEN scientists report in Nature that astrocytes, not just neurons, assemble recall-specific Fos-positive ensembles that stabilize long-term emotional memories in mice.
- A whole-brain, astrocyte-specific, time-locked Fos labeling system mapped activity across learning versus recall, showing strong astrocyte activation only during recall.
- Single-cell RNA sequencing found days-later upregulation of alpha and beta adrenoreceptors in tagged astrocytes, creating a noradrenaline-sensitive trace.
- Recall-linked astrocyte activation depended on input from amygdala engram neurons plus concurrent noradrenergic signaling.
- Causal tests showed that blocking Fos+ astrocyte signaling destabilized recall, while forced activation amplified and generalized aversive memories, with therapeutic and AI implications noted as preliminary.