What’s funny about this video? At one level, it’s the idea that a 9 month old (or however old this kid is – he’s cruising, so he’s probably right around there) knows his dance moves well enough to do what he does with his right arm at 0:39. We all know that his brain is basically producing these movements all on its own, in the absence of the cultural references that would be guiding 18 year olds out for a night of clubbing.
The second thing that’s funny is that at certain points his nervous system seems to randomly produce partial moves. For example, at 0:55 he engages in a series of right leg kicks that look like part of a coherent dance sequence, but which as viewers we know are probably occuring completely outside his consciousness.
The neuroself explanation is that what we’re witnessing is rogue central pattern generators (CPG’s for short) taking momentary control over individual limbs. What’s a central pattern generator? Essentially its any neural network – the one for this kid’s leg is in his spinal cord, for example, but the one for his arm movement is more likely in his basal ganglia + brainstem + spinal cord – that once triggered produces a sequence of muscle contractions that produce a pattern. No thought or conscious control is required to produce the entire pattern; you just have to get it going, and it will keep going while you turn your attention to other matters. In fact, it can trigger all by itself, outside of your awareness completely – as is likely the case with most of this kid’s moves.
Here’s a few CPG’s you’ve probably used already today:
- Sitting down (or up)
- Brushing your teeth
- Typing various words or part words. For example, in this sentence, ‘ing’ is a CPG for me that I actually struggle with a fair amount; if I ever type a word ending in -ied, as in ‘cried’, which is far less common an ending than -ing, typing the ‘i’ will often trigger an ‘ing’ CPG when what I consciously wanted was ‘ied’. And so when I go back and read my sentence, instead of writing ‘my baby cried all last night’ I will have written ‘my baby crying all last night.’
The meta concept here is kind of cool. One way of looking at your life is that it has been one long endeavor to learn new CPGs. I, for example, was born not knowing how to walk, or sit, or brush my teeth, or type, or ride a bike – but now I don’t have to think about any of them. Learning French, or how to play tennis, or how to drive, or even more complex sequences like dancing or swiping your metrocard in the subway turnstile, are all efforts to actively ‘download’ skills into CPGs.
This process involves conscious attention, and a lot of prefrontal cortex (PFC) planning, as well as a fair amount of conditioning – you reward and punish your various efforts to learn the CPG until your forehand is just right. Once the sequence is repeated a few dozen times, it begins to be ‘memorized’ by regions in the center of your brain, particularly the basal ganglia and cerebelllum, and is recursively pushed down from the PFC towards the spinal cord.
You can almost imagine your brain ‘swallowing’ patterns and putting them on as weight down below, where they are carried around and pulled out when necessary.
The little boy in this video was essentially born with a whole set of what we might call micro-CPGs for controlling individual limbs; he’s in the process of memorizing how to sequence them to produce the macro-CPGs, like some hot moves on the dance floor, that make culture possible.
– Peter Freed, MD
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