MRI amygdala volume in Williams syndrome

One of the most intriguing characteristics of Williams Syndrome individuals is their
hypersociability. The amygdala has been consistently implicated in the etiology of this
social profile, particularly given its role in emotional and social behavior. This study
examined amygdala volume and symmetry in WS individuals and in age and sex matched
controls. Magnetic resonance imaging scans were obtained on a GE 1.5-T magnet with 1.5-
mm contiguous slices and were used to measure whole gray matter, white matter and
cerebrospinal fluid volumes, as well as amygdala volume (right and left). Results revealed
significantly reduced intracranial volume in individuals with WS, compared with controls.
There were no differences between groups in absolute amygdalae volume, although there
was a relative increase in amygdalae volumes, when adjusted for total intracranial
content. There were no inter-hemispheric differences in amygdalae volumes in both
groups. These results suggest a relative increase in amygdala volume in WS compared with
healthy controls that likely reflects abnormal neurodevelopmental processes of midline
brain structures.
This research was supported by the grants PIC/IC/83290/2007 from Fundac¸a˜o para a Cieˆncia e Tecnologia (Portugal) and
Fundacio´n Alicia Koplowitz. (V convocatoria de 2009. Ayudas a la investigacio´n en psiquiatrı´a de la infancia y adolescencia
enfermedades neurodegenerativas tempranas)