Human Neurons with 'Tricks Up Their Sleeves'

Who isn’t curious, at some level at least, about how human brains process all the complicated inputs and outputs that our daily lives require? Neurobiologists take that curiosity to the top floor. Their recent discovery of a new function for certain neurons has suddenly added a new dimension to these tiny processors along with a new take on how they came to be in the first place.¹

The researchers attached a tiny patch clamp to individual nerve cells,² and they pushed a miniscule voltage into each neuron and detected its responses. Textbooks have long taught that electric (or action) potentials that occur when sodium, chloride, and potassium ions pass through channel proteins in a wave pattern down the slender cells. Now these researchers have discovered an entirely new class of channels that instead uses calcium.

The rat brains they tested do not have this channel. Some suspect this calcium voltage system is another uniquely human attribute. What does this newfound nerve kit do for us?

The team made a new model of neuron function based on their find. It now includes a logic gate called an XOR. It’s like a tiny transistor or switch. We already knew that neurons use AND logic gates, which convey a signal only with two inputs, X and Y. And we knew of their OR gates, which convey a signal with X or Y as inputs. XOR gates convey a signal only when either X or Y are inputs, but not when both or neither are inputs.

They just discovered a stunning new dimension of processing power in the human brain.

A recent news summary of the find said, “Excitingly, the discovery hints that our brains might be even more powerful units of computation than we realized.”³ Similarly, a brief overview of the article in Science said, “Dual somatodendritic recordings revealed previously unknown classes of action potentials in the dendrites of these neurons, which make their activity far more complex than has been previously thought.”⁴

Now who deserves credit for crafting our well-engineered neurons with protein channels that precisely manipulate individual ions in immense systems of logic gates? The answer may depend more on one’s starting assumptions than any data from the physical world.

If a Creator is arbitrarily disallowed from consideration as the Originator, then nature must have figured it out. Accordingly, Science Alert wrote, “More work needs to be done to see…if similar mechanisms have evolved elsewhere in the animal kingdom.”³ Has anybody seen natural, unintentional processes engineer voltage channels or arrange them into logic gates? How ironic that we use our uber-neurons to imagine any source other than a divine Engineer to have invented them.

References

1. Gidon, A., et al. 2023. Dendritic action potentials and computation in human layer 2/3 cortical neurons. Science. 367: 83-87.

2. They targeted pyramidal cells from the 2/3 layer of human outer cerebral cortex from recently resected brain tissue from surgeries on epileptic patients, plus brain tumor and rat cortex tissue.

3. McRae, M. A First-of-Its-Kind Signal Has Been Detected in The Human Brain. Science Alert. Posted on April 19, 2023, accessed April 21, 2019.

4. Dendritic action potentials and computation in human layer 2/3 cortical neurons. Science. Posted on science.org January 3, 2023, accessed April 14, 2023.

https://www.icr.org/article/neurons-with-tricks/