Differences In Amygdala Volume Research Articles

Amygdala volume and psychopathology in childhood complex partial seizures

Objective The purpose of this study was to compare amygdala volume in children with cryptogenic epilepsy who have complex partial seizures (CPS) with that of age- and gender-matched normal children. The relationship of amygdala volume to seizure variables and presence of psychopathology was also examined in these patients. Methods Twenty-eight children with cryptogenic epilepsy, all of whom had CPS, and gender-matched normal children, all aged 6–16 years, underwent magnetic resonance imaging (MRI) at 1.5 T. Tissue was segmented, and total brain volume and amygdala volumes obtained from manual tracings were computed. Results There were no significant differences in amygdala volume between the CPS and normal groups. Within the CPS group, the children with an affective/anxiety disorder had significantly larger left amygdala volumes, as well as greater amygdala asymmetry, compared with those with no psychopathology. Exploring the association between seizure variables and amygdala volume yielded no significant predictors. Conclusions In pediatric CPS, left amygdala involvement may reflect effects of the neuropathology underlying comorbid affective or anxiety disorders on amygdala development rather than effects of ongoing seizures.

5‐HT1A receptor gene C −1019 G polymorphism and amygdala volume in borderline personality disorder

Alterations of amygdala structure and function have been repeatedly described in patients with borderline personality disorder (BPD). The aim of our study was to determine whether a functional polymorphism of the 5-hydroxytryptamine(1A) receptor (5-HTR(1A)) gene C -1019 G (identity number: rs6295 G/C) is associated with structural changes of the amygdala in patients with BPD. Twenty-five right-handed female inpatients with BPD according to DSM IV and 25 healthy controls matched for age, sex, handedness and educational status were enrolled. Brain volumetry of the amygdala was performed with a 1.5-T Magnetom Vision apparatus (Siemens, Erlangen, Germany) and analyzed by the software program 'BRAINS'. Patients who have the 5-HTR(1A) gene G allele had significantly smaller amygdala volumes than C/C genotype carriers (P = 0.02). While no difference of allelic distribution between patients and controls was detected, the described effect of 5-HTR(1A) genotype on amygdala volume was found for the whole group of patients, as well as in the subgroup of patients with comorbid major depression (P = 0.004) but not in controls. In contrast to these subgroups of BPD patients who had significant amygdala volume differences, the mean amygdala volume of the whole group of BPD patients was not significantly different from that of controls. In summary, our study provides first evidence that 5-HTR(1A) gene C -1019 G polymorphism is associated with structural changes in the limbic system of BPD patients, a finding that might be disease related and might contribute to explanation of previous discrepant results regarding amygdala volume changes in BPD. Future research is recommended to clarify possible interactions between this functional polymorphism and symptoms, course and treatment responses in this disorder.

Amygdala Volume Analysis in Female Twins with Major Depression

Previous research examining the amygdala volumes in major depressive disorder (MDD) has found conflicting evidence for association. Furthermore, few of these studies have examined differences in individuals with an onset during childhood or adolescence. This study examined amygdala volume and its potential association with early onset major depression. A community-based sample of 47 right-handed young adult female monozygotic and dizygotic twin pairs was examined. For 29 twin pairs, one twin per pair had a lifetime history of MDD, while 18 age-matched control twin pairs had no lifetime history of MDD or other Axis I disorder. Core, noncore, and total amygdala volumes were estimated based on a combination of manual tracing, automated segmentation, and expert rater regional boundary definitions. No significant differences were found in amygdala volumes between depressed, high-risk, or control subjects. However, analyses comparing control monozygotic twins to randomly created control subject pairs suggest that there are familial, perhaps genetic, influences on core and total amygdala volumes. Findings suggest that although there were no significant differences in amygdala volumes between groups, familial factors influence amygdala volumes. Discrepancies between studies measuring amygdala volume in MDD may be due to differences in amygdala boundary definitions.

Amygdala–Prefrontal Disconnection in Borderline Personality Disorder

Abnormal fronto-amygdala circuitry has been implicated in impulsive aggression, a core symptom of borderline personality disorder (BPD). We examined relative glucose metabolic rate (rGMR) at rest and after m-CPP (meta-chloropiperazine) with (18)fluorodeoxyglucose (FDG) with positron emission tomography (PET) in 26 impulsive aggressive (IED)-BPD patients and 24 controls. Brain edges/amygdala were visually traced on MRI scans co-registered to PET scans; rGMR was obtained for ventral and dorsal regions of the amygdala and Brodmann areas within the prefrontal cortex (PFC). Correlation coefficients were calculated between rGMR for dorsal/ventral amygdala regions and PFC. Additionally, amygdala volumes and rGMR were examined in BPD and controls. Correlations PFC/amygdala Placebo: Controls showed significant positive correlations between right orbitofrontal (OFC) and ventral, but not dorsal, amygdala. Patients showed only weak correlations between amygdala and the anterior PFC, with no distinction between dorsal and ventral amygdala. Correlations PFC/amygdala: m-CPP response: Controls showed positive correlations between OFC and amygdala regions, whereas patients showed positive correlations between dorsolateral PFC and amygdala. Group differences between interregional correlational matrices were highly significant. Amygdala volume/metabolism: No group differences were found for amygdala volume, or metabolism in the placebo condition or in response to meta-chloropiperazine (m-CPP). We demonstrated a tight coupling of metabolic activity between right OFC and ventral amygdala in healthy subjects with dorsoventral differences in amygdala circuitry, not present in IED-BPD. We demonstrated no significant differences in amygdala volumes or metabolism between BPD patients and controls.