2012年2月13日,，PNAS雜志刊登了一項(xiàng)研究表明，兒童時(shí)期受到身體及精神虐待,，會(huì)導(dǎo)致成年人大腦中某些非常重要的區(qū)域萎縮,，減少大腦海馬體體積，而海馬體與人的認(rèn)知能力,、記憶力,、情緒控制力相關(guān)。
研究人員使用核磁共振成像技術(shù)對(duì)193位18到25歲青年進(jìn)行大腦掃描,，然后研究人員為他們做了一份詳細(xì)的個(gè)人經(jīng)歷調(diào)查,。結(jié)果顯示，那些兒時(shí)受過虐待,、漠視的人,，大腦海馬體比健康成長(zhǎng)的人平均小6%。
除了海馬體,，腦下腳也受到影響,，腦下腳負(fù)責(zé)將海馬體的信號(hào)傳播給大腦其他區(qū)域，如多巴胺系統(tǒng),，多巴胺也被稱為大腦的獎(jiǎng)賞中樞,。腦下腳的縮小會(huì)增加成年后患精神分裂癥和藥物濫用的風(fēng)險(xiǎn),。
在靈長(zhǎng)類動(dòng)物試驗(yàn)中，當(dāng)壓力荷爾蒙皮質(zhì)醇接收到過大的壓力時(shí),，海馬體就會(huì)縮小,。科學(xué)家發(fā)現(xiàn)這是因?yàn)閴毫蔂柮伤竭^高抑制了海馬體中神經(jīng)元的生長(zhǎng),。而海馬體的縮小主要在兩個(gè)階段,，一個(gè)是3歲到5歲，一個(gè)是11歲到13歲,。
這項(xiàng)研究也解釋了為什么心理學(xué)家總是將許多成年人的精神疾病,，如抑郁、焦慮,、藥物濫用等歸因于幼兒時(shí)期,。哈佛大學(xué)研究人員Martin Teicher表示，兒童時(shí)受到虐待幾乎能等同于成年后的精神疾病和藥物濫用,。(生物谷 Bioon.com)
doi:10.1073/pnas.1115396109
PMC:
PMID:
Childhood maltreatment is associated with reduced volume in the hippocampal subfields CA3, dentate gyrus, and subiculum
Martin H. Teicher, Carl M. Anderson, and Ann Polcari
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.
