Brain's extensive memory capacity could be due to star-like cell structure
New Findings Suggest Astrocytes, Not Just Neurons, May Drive Memory Storage
For years, scientists assumed that neurons were the sole architects of thought and memory, but recent research suggests a different, overlooked type of brain cell may hold the key to memory storage in a way we never imagined.
This revolutionary study, published in May in the journal PNAS, proposes that astrocytes - star-shaped cells considered support cells - might be at the heart of the brain's memory-storage capacity through a newfound network architecture.
Astrocytes are maintenance workers in the brain, disposing of cell debris, feeding neurons, and regulating blood flow. They also have thin branching structures that wrap around the points where neurons exchange messages, forming tripartite synapses. You could imagine an astrocyte as an octopus with millions of tentacles, said lead author Leo Kozachkov. The head of the octopus is the cell body, and the tentacles are the processes that wrap around nearby synapses.
Despite not transmitting electrical impulses like neurons, astrocytes communicate via calcium signaling. They respond to synaptic activity by altering their internal calcium levels, releasing chemical messengers into the synapse. Think of these processes as tiny calcium computers that sense when information is sent through a synapse, passing the information to other processes, and receiving feedback in return. Ultimately, this chain reaction gets back to the neurons, which adjust their activity accordingly.
Kozachkov and his colleagues, seeking to understand the astrocytes’ function, turned to machine learning architectures capable of representing complex interactions between many actors, rather than simply capturing simple connections between pairs of units. The researchers hypothesized that astrocytes might mediate communication across thousands of neuron connections, which could explain the brain's vast storage capabilities.
They proposed that memories are stored through gradual changes in astrocytes' internal calcium patterns, triggered by the information received from neurons. Each astrocyte process functions as a distinct computational unit with a significant advantage from an energy efficiency perspective, since neurons are metabolically expensive.
"The involvement of astrocytes increases the total memory space in the brain by orders of magnitude, resolving previous discrepancies between observed brain capacity and known storage mechanisms," Kozachkov said.
Although scientists are just starting to recognize the role of astrocytes in memory formation, we still don't have clear proof that calcium-based interactions between astrocytes and neurons result in memory creation or recall. But if the model is on the right track, it could give us a new way to think about memory and memory disorders, suggesting that memory capacity can scale with astrocyte-synapse interactions in the brain.
The model may also offer potential therapeutic targets for neurological conditions like Alzheimer's and neurodegenerative diseases. By focusing on astrocyte health rather than neurons alone, the team's mathematical model could inspire the search for new therapeutic targets and improved diagnostic techniques.
Beyond neuroscience, the model could inspire AI architecture designs that mimic the human brain's energy efficiency. Such systems could use dense memory architectures to store and recall information efficiently, like the brain does. This technology could well be the game-changer for various AI applications, including voice recognition, robotics, AI assistants, brain-machine interfaces, and neuroprosthetics.
Health-and-wellness research, inspired by the earthquaking study on astrocytes' role in memory storage, could lead to fitness-and-exercise routines that optimize brain health by promoting astrocyte health. Nutrition plays a critical part in this, as a balanced diet rich in essential nutrients could support the maintenance and functionality of these crucial brain cells, thereby potentially enhancing memory capacity.
