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インスリン様増殖因子II（IGF-II）と呼ばれるタンパク質の長期記憶増強効果が，動物実験で明らかになった。IGF-IIは記憶の形成に重要とされる脳の海馬と皮質に多く存在する。これを抑制性回避学習（不快な経験を避ける学習）後のラットの海馬に注射したところ，IGF-IIを注射したラットは注射しなかったラットと比べて強く記憶を保持し，その効果は数週間続いた。細胞レベルでも，IGF-IIは神経細胞間の信号伝達を強化し，長続きさせた。記憶を増強する治療法の他，認知障害の患者に見られる記憶喪失の研究に利用できる可能性がある。（吉田素子）
Mount Sinai Researchers Find That Little-Studied Gene May Boost Long-Term Memory and Enhance Cognition
Researchers from Mount Sinai School of Medicine have identified a therapy that may enhance memory and prevent the loss of long-term memory. The research is published in the January 27th issue of Nature.
Led by Cristina Alberini, PhD, Professor of Neuroscience at Mount Sinai, the research team evaluated how a protein called insulin-like growth factor II (IGF-II), a gene expressed during brain development that declines with aging, impacts memory formation and retention.
IGF-II is enriched in the adult brain in several areas, including the hippocampus and cortex, which are known to be important for memory formation. Researchers injected the hippocampus of rats with the protein and found that IGF-II significantly improved long-term memory. The team also found that IGF-II levels increased after learning, and that when that increase was blocked long-lasting memories could not form.
"The implications of these data are far-reaching and give us new clues about how to investigate memory loss and forgetfulness in people with cognitive impairment, like those with Alzheimer’s disease, stroke, or dementia," said Dr. Alberini.
Prior to this study, very little, if anything, was known about IGF-II in adult brain functions. The researchers tested the impact of injecting IGF-II into rats after "inhibitory avoidance learning," in which the rats learn to avoid an unpleasant experience. They found that compared to control groups, the rats injected with IGF-II had a much stronger memory retention. In addition, the rats maintained an elevated memory for several weeks, while the control group showed diminished memory over the same period of time.
［単語和訳］
Researchers：研究者 Little-Studied：ほとんど研究されていない Gene：遺伝子 Boost：～を強化する Long-Term Memory：長期記憶 Enhance：～を増進する Cognition：認知
therapy：治療
PhD：博士 Neuroscience：神経科学 evaluated：～を検討した protein：タンパク質 insulin-like growth factor II：インスリン様増殖因子II expressed：発現した brain：脳 declines：減る aging：加齢 memory formation and retention：記憶の形成と保持
is enriched：豊富に含まれている hippocampus：海馬 cortex：皮質 injected～with...：～に...を注射した rats：ラット significantly：顕著に learning：学習 long-lasting：持続性の
implications：意義 far-reaching：広範囲に及ぶ clues：手掛かり memory loss：記憶喪失 forgetfulness：健忘症 cognitive impairment：認知障害 Alzheimer’s disease：アルツハイマー病 stroke：脳卒中 dementia：認知症
Prior to：～の前に inhibitory avoidance learning：抑制性回避学習 unpleasant：不快な control groups：対照群 In addition：加えて elevated：増強された diminished：減退した
