Human Neurons and Mammels

Human neurons have fewer ion channels, which might have allowed the human brain to divert energy 

to other neural processes.

Neurons communicate with each other via electrical impulses, which are produced by ion channels that control the flow of ions such as potassium and sodium. In a surprising new finding, MIT neuroscientists have shown that human neurons have a much smaller number of these channels than expected, compared to the neurons of other mammals.


The researchers hypothesize that this reduction in channel density may have helped the human brain evolve to operate more efficiently, allowing it to divert resources to other energy-intensive processes that are required to perform complex cognitive tasks.


“If the brain can save energy by reducing the density of ion channels, it can spend that energy on other neuronal or circuit processes,” says Mark Harnett, an associate professor of brain and cognitive sciences, a member of MIT’s McGovern Institute for Brain Research, and the senior author of the study.

MIT neuroscientists analyzed pyramidal neurons from several different mammalian species, including,

from left to right, ferret, guinea pig, rabbit, marmoset, macaque, and human. 

Credit: Courtesy of the researchers

Harnett and his colleagues analyzed neurons from 10 different mammals, the most extensive electrophysiological study of its kind, and identified a “building plan” that holds true for every species they looked at — except for humans. They found that as the size of neurons increases, the density of channels found in the neurons also increases.

However, human neurons proved to be a striking exception to this rule.

“Previous comparative studies established that the human brain is built like other mammalian brains, so we were surprised to find strong evidence that human neurons are special,” says former MIT graduate student Lou Beaulieu-Laroche.

Beaulieu-Laroche is the lead author of the study, which was published on November 10, 2021, in Nature.  READ MORE...

Our Consciousness

When I see red, it’s the most religious experience. Seeing red just results from photons of a certain frequency hitting the retina of my eye, which cascades electrical and biochemical pulses through my brain, in the same way a PC runs. But nothing happening in my eye or brain actually is the red colour I experience, nor are the photons or pulses. This is seemingly outside this world. Some say my brain is just fooling me, but I don’t accept that as I actually experience the red. But then, how can something out of this world be in our world? Andrew Kaye, 52, London.

What’s going on in your head right now? Presumably you’re having a visual experience of these words in front of you. Maybe you can hear the sound of traffic in the distance or a baby crying in the flat next door. Perhaps you’re feeling a bit tired and distracted, struggling to focus on the words on the page. Or maybe you’re feeling elated at the prospect of an enlightening read. Take a moment to attend to what it’s like to be you right now. This is what’s going on inside your head.

Or is it? There’s another, quite different story. According to neuroscience, the contents of your head are comprised of 86 billion neurons, each one linked to 10,000 others, yielding trillions of connections.

A neuron communicates with its neighbour by converting an electrical signal into a chemical signal (a neurotransmitter), which then passes across the gap in between the neurons (a synapse) to bind to a receptor in the neighbouring neuron, before being converted back into an electrical signal. From these basic building blocks, huge networks of electro-chemical communication are built up.  TO READ ENTIRE ARTICLE, CLICK HERE...