lunedì 9 agosto 2010

Human brains have 'Life of Brian' mechanism


In A classic Monty Python moment, a chirpy, long-haired man on a crucifix urges others around him in a similar predicament to cheer up. Now neurologists have discovered what might be described as a "Life of Brian" brain mechanism that encourages us to look on the bright side of life - even when confronted by thoughts of mortality.

Shihui Han of Peking University, China, found activity in brain regions that normally deal with negative emotions and self-awareness are dampened when we process ideas about death. Han and colleagues placed 20 volunteers in functional MRI brain scanners while death-related words, such as graveyard, corpse, behead and slay, flashed up on a screen. Neutral and negative words were also displayed.

Unsurprisingly, words related to death activated brain areas already known to process unpleasant or threatening notions. More interestingly, they were associated with comparatively lower activity in the insula and the mid-cingulate (Neuropsychologia, DOI: 10.1016/j.neuropsychologia.2010.07.026).

The insula is associated with sense of self and awareness of sensations and movement. Further tests showed that the more participants associated specific words with death, the lower the activity in the insula. Damage to this region is associated with reduced emotional awareness and expression, sometimes resulting in socially inappropriate behaviour.

The mid-cingulate plays a role in regulating emotions and generating motor responses to threatening or emotionally unpleasant stimuli. People with smaller than average mid-cingulates are at increased risk of depression and attention deficit hyperactivity disorder.

"This study is interesting in that it looks at the awareness of death - a uniquely human quality," says Philip Servos, a cognitive neuroscientist at Wilfrid Laurier University in Waterloo, Canada. "It's not surprising that we have the ability to suppress our emotions in this context. What is unexpected is that it is expressed in these two relatively archaic structures in the brain."

Nessun commento:

Posta un commento