近日，一項發(fā)表在《美國科學院院報》（PNAS）上的研究提出,，兒童期遭到虐待可能破壞神經(jīng)組織的發(fā)育,，因此受害者——即便是成年之后——可能表現(xiàn)出大腦特定區(qū)域的容量減少。
虐待兒童的情況在美國比較突出,，每年有4500多名兒童因為受虐待而住院,，其中約300人因所受傷害過于嚴重而死亡。美國耶魯大學醫(yī)學院的學者分析了美國衛(wèi)生保健研究與質量局2006年兒童住院數(shù)據(jù)庫后發(fā)現(xiàn),，美國當年共有4569名兒童因為遭嚴重虐待而住院接受治療,，其中1歲以下的兒童比例最高。每10萬名1歲以下兒童中,，就有58.2人因受虐嚴重而住院,。專家指出，這些數(shù)據(jù)比美國兒童患嬰兒猝死綜合征的比例還高,。
Martin Teicher及其同事征召了193名未經(jīng)治療的年齡在18到25歲的成年人參與該研究,。這組科研人員首先進行了訪談從而確定這些受試者在童年期是否目擊過暴力或者曾經(jīng)暴露于身體或性的虐待、身體或精神的忽視,、嚴重的分離或喪失,、語言虐待,，或者父母的爭吵。這些受試者然后接受了大腦MRI掃描,，以及通過成像軟件進行大腦容量測量,。
與其他受試者相比，那些受到兒童期虐待的受試者的海馬區(qū)的3個關鍵部分的容量減少了5.8%到6.5%,。海馬區(qū)是與情感,、記憶以及其他功能有聯(lián)系的一個大腦區(qū)域?？蒲腥藛T此前確定了在未成熟而非成年的海馬區(qū)的3個細胞群對壓力做出響應而釋放出一種激素,。這組作者提出，讓發(fā)育中的海馬區(qū)接觸過量的這種激素可能影響神經(jīng)元發(fā)育,，這可能減少腦容量,。
作者說，這種改變可能有助于揭示為什么與虐待有關的早期逆境常常導致之后許多的精神疾病,，諸如抑郁癥,、毒品成癮以及其他精神衛(wèi)生問題。（生物谷Bioon.com）
doi:10.1073/pnas.1115396109
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Childhood maltreatment is associated with reduced volume in the hippocampal subfields CA3, dentate gyrus, and subiculum
Martin H. Teichera,b,1,2, Carl M. Andersona,b,c,1, and Ann Polcaria
Childhood maltreatment or abuse is a major risk factor for mood, anxiety, substance abuse, psychotic, and personality disorders, and it is associated with reduced adult hippocampal volume, particularly on the left side. Translational studies show that the key consequences of stress exposure on the hippocampus are suppression of neurogenesis in the dentate gyrus (DG) and dendritic remodeling in the cornu ammonis (CA), particularly the CA3 subfield. The hypothesis that maltreatment is associated with volume reductions in 3-T MRI subfields containing the DG and CA3 was assessed and made practical by newly released automatic segmentation routines for FreeSurfer. The sample consisted of 193 unmedicated right-handed subjects (38% male, 21.9 ± 2.1 y of age) selected from the community. Maltreatment was quantified using the Adverse Childhood Experience study and Childhood Trauma Questionnaire scores. The strongest associations between maltreatment and volume were observed in the left CA2-CA3 and CA4-DG subfields, and were not mediated by histories of major depression or posttraumatic stress disorder. Comparing subjects with high vs. low scores on the Childhood Trauma Questionnaire and Adverse Childhood Experience study showed an average volume reduction of 6.3% and 6.1% in the left CA2-CA3 and CA4-DG, respectively. Volume reductions in the CA1 and fimbria were 44% and 60% smaller than in the CA2-CA3. Interestingly, maltreatment was associated with 4.2% and 4.3% reductions in the left presubiculum and subiculum, respectively. These findings support the hypothesis that exposure to early stress in humans, as in other animals, affects hippocampal subfield development.
