reference KSP, neuron for actions and action groups.
1 neuron control 1 muscle ,set key bind for every muscle. add another 5 neuron to control 1 action group(whole finger),add another 10 neuron to control whole hand with one key bind. now you get grab action.
if player keep build up the action group , they can finally use a w to walk forward, e to eat ,f to grab.