Associative array. At the heart of almost every joke there are references that arise in the course of brain activity, thanks to the neurons responsible for this section.
Apparently, there is no separate center of humor in the brain. A number of sequential processes take place in the perception of jokes:
Identifying a potential joke, understanding it and evaluating it as funny / unfunny / repetitive requires thinking and memory to work together. This is usually accompanied by activation of the prefrontal and temporal cortex.
The signal for the activation of emotional centers that trigger the very reaction of laughter, if the joke seemed funny, probably comes from the area of the left superior frontal gyrus. At least, it is described that artificial stimulation of this area leads to the fact that everything seems funny at all (sci-hub.org)
Actually, the activation of emotional centers and the emergence of positive emotions. Usually when a person is happy, feels pleasure, is in a state of euphoria, etc. activity of the tonsils and the nucleus accumbens is observed, first of all.
Motor reactions (smile, laughter, etc.).