Introducing the brain: new synapse signals: (Introduction)

by David Turell , Thursday, February 29, 2024, 20:22 (266 days ago) @ David Turell

A calcium channel:

https://www.sciencealert.com/a-first-of-its-kind-signal-was-detected-in-the-human-brain...

"Brains – especially those of the human variety – are often compared to computers. The analogy has its limits, but on some levels they perform tasks in similar ways.

"Both use the power of an electrical voltage to carry out various operations. In computers it's in the form of a rather simple flow of electrons through intersections called transistors.

"In neurons, the signal is in the form of a wave of opening and closing channels that exchange charged particles such as sodium, chloride, and potassium. This pulse of flowing ions is called an action potential.

"Instead of transistors, neurons manage these messages chemically at the end of branches called dendrites.

***

"Dendrites are the traffic lights of our nervous system. If an action potential is significant enough, it can be passed on to other nerves, which can block or pass on the message.

"This is the logical underpinnings of our brain – ripples of voltage that can be communicated collectively in two forms: either an AND message (if x and y are triggered, the message is passed on); or an OR message (if x or y is triggered, the message is passed on).

"Arguably, nowhere is this more complex than in the dense, wrinkled outer section of the human central nervous system; the cerebral cortex. The deeper second and third layers are especially thick, packed with branches that carry out high order functions we associate with sensation, thought, and motor control.

***

"While the team had carried out similar experiments on rats, the kinds of signals they observed buzzing through the human cells were very different.

"More importantly, when they dosed the cells with a sodium channel blocker called tetrodotoxin, they still found a signal. Only by blocking calcium did all fall quiet.

"Finding an action-potential mediated by calcium is interesting enough. But modelling the way this sensitive new kind of signal worked in the cortex revealed a surprise.

"In addition to the logical AND and OR-type functions, these individual neurons could act as 'exclusive' OR (XOR) intersections, which only permit a signal when another signal is graded in a particular fashion.

"'Traditionally, the XOR operation has been thought to require a network solution," the researchers wrote.

"More work needs to be done to see how dCaAPs behave across entire neurons, and in a living system. Not to mention whether it's a human-thing, or if similar mechanisms have evolved elsewhere in the animal kingdom.

"Technology is also looking to our own nervous system for inspiration on how to develop better hardware; knowing our own individual cells have a few more tricks up their sleeves could lead to new ways to network transistors.

"Exactly how this new logic tool squeezed into a single nerve cell translates into higher functions is a question for future researchers to answer."

Comment: this very precise control of electrical potential strengths is what makes our brain so special. This intricate design is not by chance.