HAVE YOU EVER THOUGHT OF THE MECHANISM BEHIND LAUGHTER?

I looked back on this incident that took place on Sunday during a sermon in church. Something got my sister laughing and when we had eye contact, I couldn’t help but also laugh. It was wrong to laugh at such odd hour but it was contagious so i had to.
There are also instances where I find myself laughing at something and others don’t find such thing funny. This made me ponder on the mechanism behind laughter.

image source|CC0

Laughter is the psychological response to humor displayed by a set of gestures and sound production. It is carried out in response to a stimuli and commonly consists of rhythmic, audible contractions of the diaphragm and other parts of the respiratory system. The study of laughter is called gelotology.

Laughter reduces stress hormones such as ephinephrine, cortisol, and adrenaline. The heart, diaphragm and abs usually undergo a physical exercise during the process of laughing.

In a research by scientists, it has been discovered that the parts of the brain involved in laughter are;

• Left side of the cortex
• The frontal lobe
• Right hemisphere of the cortex
• Sensory processing area of the occipital lobe
• Motor sections
  
  image source|CC0
  When a person finds something funny, it is detected by the left inferior frontal lobe and posterior temporal lobe of the brain. If any part of the brain mentioned above experiences a damage, it could impair one’s sense of humour and response to it.
  There is a network of limbic system in the brain formed by the amygdala, hypothalamus, thalamus and hippocampus which are involved in emotional and motivation behavior. The amygdala of the brain releases a chemical messenger called, dopamine and spindle neurons which transmit the feeling of happiness to other parts thereby increasing the production of hormones like endorphin and neurotransmitters. The median part of the hypothalamus is involved in the production of loud and uncontrollable laughter.

During a hearty laugh, changes are noticed to occur in many parts of the body. Fifteen facial muscles contract into a smile and stimulation of the zygomatic major muscle is experienced.

image source|CC0

In the respiratory system, the epiglottis closes the larynx halfway thereby causing the inhalation of air to occur irregularly. Under certain conditions, the tear duct can also be activated which makes the face become moist and red in most cases.

Robert Provine discovered that in humans, there is variation on a basic form in laughter. These variations consists of short, vowel-like notes which are repeated every 210 miliseconds.
There is a little spike in the blood pressure and heart rate during laughter because it does not emerge from our conscious mind but from the pre-cognitive brain.

Laughter is a universal language understood by all humans, it is a form of exercise for the body and it also plays a major role in social behavior.
REFERENCES
source 1
source 2
source 3
source 4