London, Feb 27: When it comes to aggression, size does matter. Scientists have suggested the level of aggression, belligerence and anxiety exhibited by adolescents is directly linked to variation in the size of their brain. Traits in adoloscents such as ''lying'' and ''talking back to parents,'' were taken into account by the scientists, Telegraph reported. Each adolescent participant in the study then had his or her brain structure mapped using a magnetic resonance imaging (MRI) scanner.
The researchers found that a larger than average 'amygdale' which is 'an almond-shaped brain structure known to be involved in emotions and memory was associated with longer duration of aggression in both boys and girls'. Boys with a smaller left anterior cingulate cortex (ACC) than right ACC, exhibited more anxious behaviour and ''whined'' more. ''Increased baseline amygdala activity has been reported in aggressive adult populations, and structural amygdala abnormalities have been reported in adult psychopathologies marked by impulsivity and aggressive behaviour, such as borderline personality disorder, '' Lead author Dr Nicholas Allen, from the University of Melbourne, said.
There was growing evidence that major changes to the structure of the brain took place in early adolescence which could significantly affect mental, social and emotional development,'' added Dr Allen.
These neural changes are believed to underlie a shift from behaviour that is driven by effective impulses to more regulated behaviour that is guided by consideration of future personal and social consequences.
Such changes mark adolescence as a critical period during which to examine the neural contributions to affective behaviour, particularly emotion regulation.