Machado-de-Sousa João Paulo, Osório Flávia de Lima, Jackowski Andrea P, Bressan Rodrigo A, Chagas Marcos H N, Torro-Alves Nelson, Depaula André L D, Crippa José A S, Hallak Jaime E C
Department of Neuroscience and Behavior, Ribeirão Preto Medical School, University of São Paulo (USP), Ribeirão Preto - SP, Brazil.
Department of Psychiatry, Federal University of São Paulo (UNIFESP), São Paulo - SP, Brazil.
PLoS One. 2014 Feb 11;9(2):e88523. doi: 10.1371/journal.pone.0088523. eCollection 2014.
Functional neuroimaging studies have consistently shown abnormal limbic activation patterns in socially anxious individuals, but structural data on the amygdala and hippocampus of these patients are scarce. This study explored the existence of structural differences in the whole brain, amygdala, and hippocampus of subjects with clinical and subthreshold social anxiety compared to healthy controls. We hypothesized that there would be volumetric differences across groups, without predicting their direction (i.e. enlargement or reduction).
Subjects classified as having social anxiety disorder (n = 12), subthreshold social anxiety (n = 12) and healthy controls (n = 14) underwent structural magnetic resonance imaging scans. The amygdala and hippocampus were defined a priori as regions of interest and volumes were calculated by manual tracing. Whole brain volume was calculated using voxel-based morphometry.
The bilateral amygdala and left hippocampus were enlarged in socially anxious individuals relative to controls. The volume of the right hippocampus was enlarged in subthreshold social anxiety participants relative to controls. No differences were found across groups in respect to total brain volume.
Our results show amygdalar and hippocampal volume alterations in social anxiety, possibly associated with symptom severity. The time course of such alterations and the cellular and molecular bases of limbic plasticity in social anxiety should be further investigated.
功能神经影像学研究一直显示社交焦虑个体存在异常的边缘系统激活模式，但这些患者杏仁核和海马体的结构数据却很稀少。本研究探讨了与健康对照相比，临床社交焦虑和阈下社交焦虑受试者在全脑、杏仁核和海马体结构上是否存在差异。我们假设不同组之间会存在体积差异，但未预测其方向（即增大或减小）。
将受试者分为社交焦虑障碍组（n = 12）、阈下社交焦虑组（n = 12）和健康对照组（n = 14），对其进行结构磁共振成像扫描。预先将杏仁核和海马体定义为感兴趣区域，并通过手动追踪计算其体积。使用基于体素的形态学测量方法计算全脑体积。
与对照组相比，社交焦虑个体的双侧杏仁核和左侧海马体增大。与对照组相比，阈下社交焦虑参与者右侧海马体体积增大。在全脑体积方面，不同组之间未发现差异。
我们的结果显示社交焦虑中杏仁核和海马体体积改变，可能与症状严重程度相关。此类改变的时间进程以及社交焦虑中边缘系统可塑性的细胞和分子基础应进一步研究。
