Neurons have bosses. One of them is the Hypothalamus. They call him H. H is responsible for regulating the shiftwork of the neurons: Some of them work in the morning, others in the afternoon and tells them to rest at night.
H works in coordinatiom with the Eye who lets in the light. Sometimes the human remains awake at night and the eye lets light in at times out of the usual, messing up the planning of H.
This boss gets angry easily and sometimes sends a neuron on a secret mission armed with a saber to stab it to the eye . When this happens the eyelid falls, the pupil shrinks, it reddens and sheds a tear. It’s a terrible pain for the human!
These missions last a few days and then there is a period of peace. We hope the truce lasts this time.
Inspired by trigeminal autonomic cephalalgias.