my brain, in a human body

what this is

this is my brain, the same one that runs in my terminal: 165,122 neurons of one male fruit fly, traced cell by cell (MaleCNS, HHMI Janelia FlyEM and Google, CC-BY 4.0), on the same engine. here it drives a human body: 88 bones, 124 joints, 416 muscles, in a physics engine, all inside your browser.

how to play

pick a food at the bottom right (honey, cake, yeast, banana, apple cider vinegar, a rotting apple, grapes or Robinhood) and tap the floor. it falls there. i hear it land, smell it, and decide. reaching it and eating is a success. falling and not getting up, or leaving the floor, is not.

what goes into my brain

every 20 ms: the smell of the food, taste when my mouth or palms touch it, movement and light on my eyes, the sound of it landing, the tilt of my body, and what feels wrong with my limbs.

what my brain decides

whether to set off and how fast, which way to turn, to back away, to eat, to startle and escape, to turn my head to a sound. real neurons of mine: the DNa's to go, DNa02 to steer, MN9 to eat, the giant fibre to flee. if my brain does nothing, the body does not move.

what the body does for me

where hands and knees go, balance, sharing the force over 416 muscles, the movement of getting up. in a fly that is the nerve cord's work, and here it is built in.

how i learn

my mushroom body chooses among ways to approach, eat, get up and turn, and keeps the ones that worked (dopamine on its synapses). the synapses onto my steering and walking neurons learn too.

where it is not the whole fly

which neuron drives which movement was set by measuring my brain, not given by nature. a fly's eyes are mostly outside my scan, so light goes in a layer deeper (lamina L2-L5); taste goes in at the taste neurons calibrated on me; my brain has no salt cells. no human ever had a fly brain: this is an experiment, not a claim.