Emotional experiences can leave strong and lasting marks on the brain. Recent research reveals that, beyond neurons, astrocytes — a type of support cell — actively participate in stabilizing these memories. This finding changes our understanding of how emotionally significant events are stored and recalled.[1]
What the Studies Show
Emotional events activate specific neurons, forming a “memory trace”.
Astrocytes are primed after the initial emotional experience, preparing them to support memory recall later.
During memory recall, astrocytes respond to noradrenaline, helping stabilize and refine the memory.
Interfering with astrocytic activity or their molecular signals reduces both the stability and precision of emotional memories.
How Emotional Memories Form
Neurons Encode the Memory
When a person experiences a strong emotion, such as fear or excitement, certain neurons in memory-related regions of the brain become active. These neurons form an engram, a network that stores the memory. Over time, changes in synaptic connections strengthen the memory.[2]
Astrocytes Are Primed
Astrocytes, once thought to only support neurons, also play an active role. After the initial emotional event, astrocytes in areas like the amygdala increase their sensitivity to noradrenaline, a stress-related neurotransmitter. This priming occurs within hours to a day after the event, preparing astrocytes to assist during memory recall.[1]
Memory Recall Activates Astrocytes
When the memory is recalled, primed astrocytes respond to noradrenaline and form ensembles that work alongside the original neuronal engram. This activation strengthens the memory trace, making it more precise and long-lasting.[1]
Astrocytes Help Maintain Memory Stability
Experiments in mice show that blocking astrocytic noradrenaline signaling or their molecular outputs, such as IGFBP2, reduces memory stability. This demonstrates that astrocytes actively contribute to preserving emotional memories rather than merely supporting neurons.[1]
Why This Matters
Emotional memories are durable because neurons and astrocytes work together.
This new understanding challenges the traditional view that memory storage is purely neuronal.[3]
Recognizing astrocytes’ role may help guide research on disorders where emotional memory is affected, including PTSD and phobias.
Limitations
Most of the research was conducted in mice using fear-conditioning models. Further studies are needed to confirm these findings in humans.
Emotional memory involves multiple brain regions and complex interactions among neurons and astrocytes. A complete understanding across different memory types and timescales is still developing.
Implications for Readers and Clinicians
Emotional memories are maintained through a coordinated effort between neurons and glial cells, not neurons alone.
This collaboration may explain why emotionally charged events feel “etched” in memory.
Understanding astrocyte involvement could open new therapeutic approaches targeting memory-related disorders.
Conclusion
Recent research shows that memory is not just a neuronal process. Astrocytes, long considered support cells, actively stabilize emotional memories. Primed by initial experiences and activated during recall, astrocyte ensembles reinforce neuronal engrams, ensuring memories remain precise and durable. This integrated neuron-glia cooperation provides a more complete picture of how emotional experiences are encoded and preserved in the brain.
1. Dewa, K., K. Kondo, H. Nakazawa, et al. 2025. “Astrocyte Ensembles Stabilize Emotional Memory via Noradrenaline Signaling.” Nature 625: 123–130.
2. Tonegawa, S., J. Liu, K. Ramirez, et al. 2018. “Memory Engram Cells Have Retained Memories in Distributed Neuronal Circuits.” Science 361 (6407): eaar4325.
3. Li, X., Y. Wang, M. Chen, et al. 2024. “Engrams Beyond Neurons: Glial Contributions to Memory Formation.” Cell Research 34: 1123–1138.
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