Academics propose that electric fields generated by the nerve cells of the brain may be able to alter its molecular infrastructure.
Dr Dimitris Pinotsis is a Reader at the Centre for Mathematical Neuroscience and Psychology and the Department of Psychology at City, University of London. He is also a Research Affiliate at the Picower Institute for Learning and Memory and the Department of Brain and Cognitive Sciences at the Massachusetts Institute of Technology (MIT).
In collaboration with colleagues at MIT and Johns Hopkins University, Dr Pinotsis has proposed a novel hypothesis called ‘cytoelectric coupling’ which suggests that a well-established concept known as ‘ephaptic coupling (the brain’s small, electric fields being able to alter nerve cell firing), also extends to altering and shaping the molecular infrastructure of the brain (proteins, filaments, microtubules etc.).
The brain consists of nerve cells (neurons) that interconnect to create networks. Millions of junctions (synapses), that connect two neurons, allow them to communicate. Neurons fire as a result of electrochemical processes and this firing propagates through synapses allowing information processing and transfer across neural networks. Ephaptic coupling is the idea that, besides the direct communication via synapses, there is another level of communication between neurons: small electric fields generated by groups of neurons firing together, in turn, affect those neurons’ own activity and carry information back to them.
In a recent Perspectives Article, published in the journal, Progress in Neurobiology, Pinotsis and colleagues extended the concept of ephaptic coupling in their cytoelectric coupling hypothesis, suggesting that the brain’s electric fields might affect its molecular infrastructure too, ‘tuning’ it for efficient information processing and allowing for cognitive flexibility. They summarised findings from studies in cognitive neuroscience and developmental biology to support their hypothesis, and also highlighted how it might be tested by other academics.
Nevertheless, the research base into ephaptic coupling itself remains limited, which can be put down to how difficult it is to study: manipulating and measuring an ensemble of neurons’ or indeed a single neuron’s electric field is muddied by a whole host of factors, meaning studies have had to rely on indirect techniques to point to ephaptic coupling being at play.
Such techniques include mathematical modelling. In a related paper, Dr. Pinotsis and his colleague, Professor Earl K Miller from MIT, used mathematical models and machine learning to investigate ephaptic coupling ‘in vivo’ (in a living animal). To do this, they re-analysed neural data from a previous study, recorded from two macaque monkeys while they played a memory game. They found that a mathematical model which included ephaptic coupling effects fit this neural data better than one that did not. The study was published in the journal, Cerebral Cortex.
While research supporting the existence of ephaptic coupling is growing, some academics are still skeptical and asking for more definitive studies to demonstrate real world effects in the brain.
Speaking about the cytoelectric coupling hyphothesis, Dr Pinotsis said: