May 9, 2013
Different Brain Networks Perceive Different Types Of Laughter
Brett Smith for redOrbit.com - Your Universe Online
The human brain is capable of deciphering all kinds of social cues and interpreting them into perceptions about people or situations. Now, a group of German researchers has found that joyous or mocking laughter can spark activity in the social centers of the brain, while tickle-induced giggling does not have the same effect.
"Laughing at someone and laughing with someone leads to different social consequences," said lead author Dirk Wildgruber from the University of Tuebingen. "Specific cerebral connectivity patterns during perception of these different types of laughter presumably reflect modulation of attentional mechanisms and processing resources.
Wildgruber and his colleagues at the university began their study by looking into treatments for people with chronic anxiety disorders. The scientists found that a positive joyful laugh is processed by a different part of the brain than a negative snicker, according to their report in the open access journal PLOS ONE.
Laughter has been observed as a form of communication in a variety of different animals — from rats to primates.
“Laughing is a very strong signal in social interaction,” Wildgruber told the German Press Agency (DPA). “If you are laughed at with joy you feel accepted. If you are the victim of scornful laughter, you feel shut out of the group.”
To investigate the connection between brain activity and laughter, the team played pre-recorded samples of different types of laughter for 18 male and female right-handed volunteers while they underwent a brain imaging scan. Their goal was to discover details about "laughter perception networks"“¯within the brain.
The scientists found that tickling-induced giggling stimulates areas of the brain that interpret complex acoustic signals. On the other hand, laughter induced by happiness or mockery stimulated regions of the brain typically reserved for figuring out the intentions of others. A neural chain reaction then activates parts of the brain responsible for handling either negative or positive social cues.
In their report, the researchers theorized that participants created a mental image or scenario to interpret laughter in the context of social interactions.
"Tickling laughter typically occurs in a narrower spectrum of situations and incurs lower need for mentalizing," the authors wrote.
Wildgruber noted that the study´s findings could eventually lead to treatments for those with anxiety or other similar conditions.
"[Our findings are] really relevant for psychiatry patients," said Wildgruber. He added that conditions like anxiety, depression or schizophrenia are often associated with a disruption in the brain's ability to correctly interpret non-verbal cues.
According to the researchers, it is still unclear how patients might react to genuine laughter, as their recorded sounds were created using actors who were instructed on how to laugh. The team said they will also begin looking at how people with psychological disorders react to various laughter signals and how artificially stimulating the brain could potentially help them.
Social anxiety or paranoia is often treated with anti-depression medications known as“¯serotonin-specific reuptake inhibitor (SSRI). These drugs are believed to alleviate symptoms by increasing the amount of the neurotransmitter serotonin in the brain. They are the most widely prescribed drugs in many developed countries.