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Summary: Our brains have been likened to an orchestra, with neurons as musicians creating a symphony of thought and memory.
A recent study reveals the conductor behind this symphony: electric fields. These fields are generated by the combined electrical activity of neurons, orchestrating them into functional networks.
This research shines a light on the brain’s complex inner workings and could impact the future of brain-computer interfaces.
Key Facts:
- Electric fields generated by the collective electrical activity of neurons coordinate information across key brain regions.
- This process is made possible by a mechanism called “ephaptic coupling,” which can influence the spiking of neurons and, thus, their signaling to other neurons.
- Findings could improve our ability to read information from the brain and have implications for the design of brain-controlled prosthetics.
The “circuit” metaphor of the brain is as indisputable as it is familiar: Neurons forge direct physical connections to create functional networks, for instance to store memories or produce thoughts.
But the metaphor is also incomplete. What drives these circuits and networks to come together? New evidence suggests that at least some of this coordination comes from electric fields.
The new study in Cerebral Cortex shows that as animals played working memory games, the information about what they were remembering was coordinated across two key brain regions by the electric field that emerged from the underlying electrical activity of all participating neurons.
The field, in turn, appeared to drive the neural activity, or the fluctuations of voltage apparent across the cells’ membranes.
If the neurons are musicians in an orchestra, the brain regions are their sections, and the memory is the music they produce, the study’s authors said, then the electric field is the conductor.
The physical mechanism by which this prevailing electric field influences the membrane voltage of constituent neurons is called “ephaptic coupling.” Those membrane voltages are fundamental to brain activity.
When they cross a threshold, neurons “spike,” sending an electrical transmission that signals other neurons across connections called synapses. But any amount of electrical activity could contribute to a prevailing electric field which also influences the spiking, said study senior author Earl K. Miller, Picower Professor in the Department of Brain and Cognitive Sciences at MIT.
“Many cortical neurons spend a lot of time wavering on verge of spiking” Miller said. “Changes in their surrounding electric field can push them one way or another. It’s hard to imagine evolution not exploiting that.”
In particular, the new study showed that the electric fields drove the electrical activity of networks of neurons to produce a shared representation of the information stored in working memory, said lead author Dimitris Pinotsis, Associate Professor at City—University of London and a research affiliate in the Picower Institute.
He noted that the findings could improve the ability of scientists and engineers to read information from the brain, which could help in the design of brain-controlled prosthetics for people with paralysis.
“Using the theory of complex systems and mathematical pen and paper calculations, we predicted that the brain’s electric fields guide neurons to produce memories,” Pinotsis said.
“Our experimental data and statistical analyses support this prediction. This is an example of how mathematics and physics shed light on the brain’s fields and how they can yield insights for building brain-computer interface (BCI) devices.”
- Entire article available here.
