For decades, scientists believed that neurons were the sole masters of memory. A groundbreaking study now shows that star-shaped cells called astrocytes are not just passive bystanders but essential partners in how the brain records and recalls the past.
Researchers at Baylor College of Medicine have demonstrated that these cells work in tight coordination with neurons to create physical traces of our experiences. Published in the journal Nature, the findings reveal that without astrocytes, the brain circuit for a specific memory remains silent, preventing recall. This discovery shifts the focus of neuroscience from a neuron-centric view to a more complex picture where different cell types collaborate to keep our history alive.
Astrocytes work with neurons to form memory circuits
The human brain contains billions of neurons, but it also contains roughly an equal number of glial cells, of which astrocytes are the most abundant type.
From support cells to active partners
Historically, neuroscientists viewed astrocytes primarily as the “glue” of the nervous system. Their known jobs were to feed neurons, clean up waste, and maintain the chemical balance of the brain. While recent years have hinted that they might listen in on neuronal signals, this new study confirms they are active participants in the memory process. They do not just support the hardware; they help write the software.
Identifying “learning-associated astrocytes”
The research team found that when the brain learns something new – such as associating a specific place with a fearful event – a distinct group of astrocytes activates alongside the neurons. They termed these “learning-associated astrocytes.” These cells are physically close to the neurons involved in the memory, forming a coordinated unit or “engram” that holds the information.
The NFIA gene controls access to specific memories
The researchers identified a specific molecular key that allows these astrocytes to do their job: a gene known as NFIA.
How the gene locks in the memory
The NFIA gene produces a protein that alters the astrocyte’s activity, allowing it to listen and respond to the neurons next to it. In laboratory tests, the team found that learning experiences triggered the production of NFIA specifically in the relevant astrocytes. This protein prepares the astrocyte to help the neuronal circuit fire again later.
Evidence from fear-conditioning experiments
To prove this mechanism, the scientists used mice conditioned to feel fear in a specific environment. When they silenced the NFIA gene in the astrocytes, the mice could not recall their fear when placed back in that environment, even though the neurons were still there. Conversely, when researchers artificially activated these specific astrocytes, the mice froze in fear even in a neutral environment. This proved that the astrocyte ensemble is necessary to retrieve the memory.
New paths for treating Alzheimer’s and PTSD
Understanding that memory is a team effort between neurons and astrocytes opens entirely new doors for medicine.
Targeting star cells instead of just neurons
Most current treatments for memory disorders focus exclusively on neurons. This study suggests that in conditions like Alzheimer’s disease, the failure might lie in the astrocytes or their connection to neurons. If the NFIA mechanism is disrupted, memories might exist physically in the brain but remain inaccessible, like a file on a computer that cannot be opened. Scientists map every neuron and connection in an adult fly brain to understand these complex networks, and adding astrocytes to these maps will be the next major step.
Implications for brain diseases
This insight is also vital for conditions like Post-Traumatic Stress Disorder (PTSD), where memories are too intrusive. Therapies that specifically target astrocyte activity could theoretically help dampen traumatic memories without dulling the entire brain. By modulating how these star-shaped cells interact with neurons, doctors might one day be able to strengthen weak memories or soften painful ones with greater precision.
What you can do about it
This is fundamental research, so there is no immediate “astrocyte pill” you can take. However, general brain health advice supports all cell types in your head.
- Keep learning: The study confirms that learning physically changes your brain cells. Learn new things all the time to keep these circuits active.
- Exercise: Physical activity supports overall brain vascular health, which astrocytes help regulate. Exercise that works muscles helps neurons grow, and likely supports glia too.
- Sleep well: Astrocytes are crucial for cleaning the brain during sleep. Prioritizing rest helps them maintain a healthy environment for memory.
Sources & related information
Nature – Learning-associated astrocyte ensembles regulate memory recall – 2024
A study identifying that specific populations of astrocytes express the transcription factor NFIA to encode and retrieve memory engrams alongside neurons.
Baylor College of Medicine – Astrocytes play a key role in memory recall – 2024
A press release summarizing the discovery that astrocytes are essential for the storage and retrieval of memories by working with neurons.
0 Comments