Introducing the brain: tongue and hand relationship (Introduction)

by David Turell , Monday, August 28, 2023, 20:37 (451 days ago) @ David Turell

In some people:

https://www.quantamagazine.org/the-hidden-brain-connections-between-our-hands-and-tongu...

"One day, while threading a needle to sew a button, I noticed that my tongue was sticking out. The same thing happened later, as I carefully cut out a photograph. Then another day, as I perched precariously on a ladder painting the window frame of my house, there it was again!

***

"Yet as I would learn, our tongue and hand movements are intimately interrelated at an unconscious level. This peculiar interaction’s deep evolutionary roots even help explain how our brain can function without conscious effort.

***

"Tracing the neural anatomy of tongue and hand control to pinpoint where a short circuit might happen, we find first of all that the two are controlled by completely different nerves. This makes sense: A person who suffers a spinal cord injury that paralyzes their hands does not lose their ability to speak. That’s because the tongue is controlled by a cranial nerve, but the hands are controlled by spinal nerves.

***

"That connection is borne out by research showing that hand and mouth movements are tightly coordinated. In fact, that interplay often improves performance. Martial artists scream short explosive utterances, called kiai in karate, as they execute thrusting movements; tennis players often shout as they smack the ball. And research shows that coupling hand movements with specific mouth movements, often with vocalization, shortens the reaction time needed to do both. This neural coupling is so innate, we are usually oblivious to it, but we do this continually without awareness because the neural circuitry involved is in a region of the brain that operates automatically — it literally lies beneath brain regions providing conscious awareness.

***

"Where did this coordination come from? It likely originated in our ancient ancestors’ hand-to-mouth feeding movements and their development of language, because spoken language is typically accompanied by automatic hand movements. Presumably, hand gestures were the first type of communication to evolve, and they gradually blended with appropriate syllabic utterances — mouth sounds — that allowed for language. Indeed, functional brain imaging studies show that specific tongue and hand movements activate the same region of the brain in the premotor cortex (the F5 region). (my bold)

***

"With all these connections, it’s no wonder the tongue peeks out during moments of manual concentration. It probably just seems strange to us because we tend to think of the brain as a sophisticated machine, engineered to take in bits of information, compute them and control muscles to interact with our environment. But the brain is an agglomeration of cells, not an engineered system. It evolved to maximize survival in a complex world. To achieve that aim efficiently, the brain mixes functions in ways that can seem like something’s gone wrong, but it does have a good reason. The brain mixes tongue and hand movements with sounds and emotion because it encodes experiences and executes complex movements in a holistic way — not as discrete entities strung together like lines of computer code, but as pieces of a larger conceptual purpose and context." (my bold)

Comment: I have never experienced this connection. I would guess it is intermittent among humans. But the thought about hand and gestures before speech was developed in right on point. We still gesture with speech to add meaning. My bolds also emphasize my theory that the brain is organized to help us do everything without us realizing it.