‘Over-friendly' brain clues found[ ... Read the full report ... ]
Scientists have uncovered clues about what happens in the brain to make some people "over-friendly".
US National Institute of Mental Health experts looked at differences in the brains of people with an abnormality which makes them highly sociable.
Researchers used scans to identify areas which failed to work properly when they saw frightening faces.
In Nature Neuroscience, they say this could give clues for understanding social disorders in others.
People with the genetic condition Williams Syndrome lack around 21 genes on chromosome seven.
Their lack of fear means they will impulsively engage in social situations, even with strangers.
But they often have heightened anxiety about non-human fears, such as spiders or heights.
Andreas Meyer-Lindenberg, Ahmad R Hariri, Karen E Munoz, Carolyn B Mervis, Venkata S Mattay, Colleen A Morris, & Karen Faith Berman. Neural correlates of genetically abnormal social cognition in Williams syndrome. Nature Neuroscience Published online: 10 July 2005; [ doi:10.1038/nn1494 ].
Williams-Beuren syndrome (WBS), caused by a microdeletion of approximately 21 genes on chromosome 7q11.23, is characterized by unique hypersociability combined with increased non-social anxiety. Using functional neuroimaging, we found reduced amygdala activation in individuals with WBS for threatening faces but increased activation for threatening scenes, relative to matched normal controls. Activation and interactions of prefrontal regions linked to amygdala, especially orbitofrontal cortex, were abnormal, suggesting a genetically controlled neural circuitry for regulating human social behavior.
Anthony H. Risser | neuroscience | neuropsychology | brain