發表在8月28日《PNAS》雜志上題為'肥胖的神經行為相關性很大程度上是可遺傳的'(Neurobehavioral correlates of obesity are largely heritable)這項研究中，蒙特利爾神經研究所和醫院( Neuro )的研究人員對1200個參與者的磁共振成像( MRI )和認知測試數據進行了檢查。
他們發現，體重指數(BMI，體重/身高的平方，單位kg/㎡。成人的正常BMI數值：18.5-23.9；過重：24-27；肥胖：28-32；非常肥胖：高于32)較高的人表現出認知靈活性、延遲滿足能力、視覺空間能力和語言記憶能力降低。他們還發現，體重指數增加的人傾向于左前額葉皮質較厚、右前額葉皮質較薄。先前的研究表明，右前額葉皮層的損傷會導致進食量增加。
此外，BMI較高的受試者左側杏仁核的體積也有所增加。已有研究表明，杏仁核對食物信號起著一定的反應。他們還減少了內嗅-旁海馬結構的體積，后者與情景記憶和語境調節有關。這表明了一種模式，在這種模式下，容易肥胖的人對視覺食物線索更敏感，并且即使在考慮飲食的負面效應（比如體重增加）時，仍然難以抗拒這些食物。
鑒于許多受試者是兄弟姐妹（包括異卵雙胞胎和同卵雙胞胎），這使得研究人員能夠確定這些特征的遺傳性，以及通過體重指數(BMI)來衡量的肥胖。使用統計學方法，研究人員發現許多認知和神經特征與肥胖有遺傳聯系。這表明遺傳在肥胖中的作用至少部分通過大腦解剖和認知功能表現出來。
“這項研究將有助于制定干預措施來幫助肥胖患者。” 該研究的主要作者、愛沙尼亞塔爾圖大學神經和心理學研究所的研究員Uku Vainik說，“例如，通過認知訓練來改變神經行為因素，以提高人們抵抗食物的能力，可能會有希望。”
研究人員補充道，干預不應該僅僅集中在飲食上，還應該承認肥胖與神經行為有著基因上的聯系。這種干預可能有助于人們保持苗條身材，即便他們有遺傳特征。”
“這項工作為人類的體重在一定程度上受認知、決策和動機等高級大腦系統的控制這一理論提供了支持。此外，這些調節食物攝入的大腦系統中的個體差異似乎具有適度的遺傳性。”資深作者Alain Dagher總結。
原始出處：
Uku Vainik, Travis E. Baker, Mahsa Dadar, et.al.Neurobehavioral correlates of obesity are largely heritable. PNAS August 28, 2018
Abstract
Recent molecular genetic studies have shown that the majority of genes associated with obesity are expressed in the central nervous system. Obesity has also been associated with neurobehavioral factors such as brain morphology, cognitive performance, and personality. Here, we tested whether these neurobehavioral factors were associated with the heritable variance in obesity measured by body mass index (BMI) in the Human Connectome Project (n = 895 siblings). Phenotypically, cortical thickness findings supported the “right brain hypothesis” for obesity. Namely, increased BMI is associated with decreased cortical thickness in right frontal lobe and increased thickness in the left frontal lobe, notably in lateral prefrontal cortex. In addition, lower thickness and volume in entorhinal-parahippocampal structures and increased thickness in parietal-occipital structures in participants with higher BMI supported the role of visuospatial function in obesity. Brain morphometry results were supported by cognitive tests, which outlined a negative association between BMI and visuospatial function, verbal episodic memory, impulsivity, and cognitive flexibility. Personality–BMI correlations were inconsistent. We then aggregated the effects for each neurobehavioral factor for a behavioral genetics analysis and estimated each factor’s genetic overlap with BMI. Cognitive test scores and brain morphometry had 0.25–0.45 genetic correlations with BMI, and the phenotypic correlations with BMI were 77–89% explained by genetic factors. Neurobehavioral factors also had some genetic overlap with each other. In summary, obesity as measured by BMI has considerable genetic overlap with brain and cognitive measures. This supports the theory that obesity is inherited via brain function and may inform intervention strategies.
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