Right Caudate Volumetric Differences in Young Healthy Adults with Different Dopamine DRD2/ANKK1 Taq 1a Polymorphisms

OBJECTIVES: The aim of this study was to assess variations in caudate volume according to dopamin receptor D2/ankyin repeat and kinase domain containing 1 (DRD2/ANKK1) Taq 1a polymorphisms in young healthy adults and to evaluate the relationship between caudate volumes and psychiatric symptoms as measured by the Brief Psychiatric Rating Scale. METHODS: Genetic information regarding DRD2/ANKK1 Taq 1a and T1-weighted brain magnetic resonance images were acquired from 30 young healthy adults. Automatic segmentation of caudate was performed using the FreeSurfer program. RESULTS: Individuals with A2 homozygotes of DRD2/ANKK1 Taq 1a polymorphisms (n = 10) had greater right caudate volumes compared to those with A1 allele (s)(18.4% greater ; p = 0.019). Right caudate volumes were negatively associated with total scores of the Brief Psychiatric Rating Scale (beta=-0.50 ; p = 0.016). CONCLUSIONS: Our findings suggest the possibility that DRD2/ANKK1 Taq 1a polymorphisms may underlie the psychiatric symptoms by influencing the structure of the right caudate.

The Relationship between Harm Avoidance Temperament and Right Frontal and Left Parietal Lobes in Young Adults: A Cortical Thickness Analysis

OBJECTIVES: Increasing evidence suggests the presence of neurobiological bases for temperamental characteristics in humans. Brain correlates of harm avoidance(HA) have been most extensively studied using functional and structural brain imaging methods due to its potential link with anxiety and depressive disorders. To date, however, we are not aware of any reports that have examined the potential relationship between HA levels and regional cortical thickness. The aim of the current study is to examine the cortical thickness which is associated with HA temperament in healthy young subjects. METHODS: Twenty-eight young, healthy individuals(13 men and 15 women, mean age, 29.4 +/- 6.3 years) were screened for eligibility and administered the Korean version of the Cloninger's Temperament and Character Inventory and underwent high-resolution structural magnetic resonance imaging scanning. RESULTS: HA was associated with cortical thickness in the right superior frontal cortex and in the left parietal cortex, adjusted for age and sex and corrected for multiple comparisons using the permutation testing method. CONCLUSION: Individual temperamental differences in HA are associated with structural variations in specific areas of the brain. The fact that these brain regions are involved in top-down modulations of subcortical fear reactions adds functional significance to current findings.