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Major depressive disorder may be defined by a distinct gut microbiome
Scientists have identified 3 bacteriophages, 47 bacterial species, and 50 fecal metabolites that were significantly more or less abundant in people with major depressive disorder (MDD) compared with healthy controls, according to a study in 311 individuals. The findings provide evidence that MDD may be characterized by gut microbiome disturbances. Jian Yang and colleagues also […]
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Common neural circuit and potential target for anxiety and obsessive-compulsive disorder
In a study recently published in PNAS, Dr. Jing-Ning Zhu’s group in Nanjing University reports that a glutamatergic neuronal circuitry from the prelimbic prefrontal cortex (PrL) to the nucleus accumbens (NAc) core is responsible for co-occurrence of anxiety- and obsessive-compulsive-like behaviors. Notably, activation of the histamine presynaptic H3 heteroreceptor localized in the PrL-NAc glutamatergic terminals […]
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Scientists reverse age-related vision loss, eye damage from glaucoma in mice
Proof-of-concept study represents first successful attempt to reverse the aging clock in animals through epigenetic reprogramming. Scientists turned on embryonic genes to reprogram cells of mouse retinas. Approach reversed glaucoma-induced eye damage in animals. Approach also restored age-related vision loss in elderly mice. Work spells promise for using same approach in other tissues, organs beyond […]
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Study identifies novel mechanisms that cause protein clumping in brain diseases
A team of researchers at the Case Western Reserve University School of Medicine has taken a major step toward understanding the mechanisms involved in the formation of large clumps of tau protein, a hallmark of Alzheimer’s disease and several other neurodegenerative disorders. Their findings may help to better understand the pathological process and possibly lead […]
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Drug Reverses Age-Related Mental Decline Within Days
Just a few doses of an experimental drug can reverse age-related declines in memory and mental flexibility in mice, according to a new study by UC San Francisco scientists. The drug, called ISRIB, has already been shown in laboratory studies to restore memory function months after traumatic brain injury (TBI), reverse cognitive impairments in Down […]
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新的检测方式可以在症状出现之前发现阿尔茨海默病的早早期变化
在整个疾病过程中，β-淀粉样蛋白和磷酸化tau蛋白(p-tau)从大脑释放到脑脊液中，释放的蛋白质的量被用作阿尔茨海默病临床诊断的可靠替代指标。 正常情况下，脑脊液中淀粉样蛋白水平在p-tau出现前几年就会出现异常。目前p-tau的临床测试结果在记忆缺陷开始进展时变得异常，这使得人们很难在早早期阶段识别出患者。该研究旨在探测阿尔兹海默病早早期，p-tau的变化模式，研究人员测试了三种新的CSF p-tau生物标记，它们在苏氨酸181和苏氨酸217上被N末端伴侣抗体磷酸化，在苏氨酸231上被中间区域伴侣抗体磷酸化。将它们与作为p-tau测量金标准的Elecsys法作比较。 该研究证明当仅检测到β-淀粉样蛋白（Aβ）病理的细微变化时，这些新的p-tau生物标记物在临床前阿尔茨海默氏症中增加得更为显著，并且可以准确地区分Aβ阳性和Aβ阴性的认知能力未受损的个体。此外，该研究还发现，新型血浆N‐末端 p‐tau 181生物标志物在临床前阶段轻度但显著升高。这些结果支持了阿尔茨海默病临床前神经元tau代谢的早期变化（可能是对Aβ暴露的反应）可以通过这些新的p‐tau检测方法检测出来。 该研究可能改变未来的临床实践，改善无症状和有症状阶段的阿尔茨海默氏病的诊断。
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通过大脑的视觉“词典”来阅读
阅读是一种快速且分散的过程，涉及腹侧视觉流的多个组成部分。为了理解给予我们识别文字能力的神经成分及其它们之间的相互作用，研究人员在一大批受试者中进行了颅内直接录音，该方法能够在整个左腹枕颞皮层中分离出视觉单词识别的时空动态。 研究人员发现中梭状皮质是第一个对词汇能力敏感的大脑区域，先于传统的视觉单词形式区域，其激活的大小和持续时间取决于自然语言的统计数据。有关词汇性和词频的信息从该区域向后传播到视觉单词形成区域以及更早的视觉皮层，而视觉皮层虽然较早活动，但较晚才表现出对单词的敏感性。此外，对该区域的直接电刺激会导致阅读停滞，进一步说明了其在阅读中的关键作用。中梭状皮层对亚词汇和词汇特征的这种独特敏感性表明，它作为正字词典的中心角色，即视觉词汇形式的长期记忆表征。 这项研究旨在增进人们对阅读方式的理解，并有望帮助有阅读障碍的人，提高其学习能力。
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科学家揭示大脑中血清素促进耐心的区域
日本的一项研究表明了大脑中通过血清素的作用来促进耐心的区域。血清素是一种著名的行为神经调节剂，帮助调节情绪，睡眠周期和食欲，这项研究表明血清素的释放对提高小鼠的耐心也起着至关重要的作用，它增加了小鼠等待食物奖励的时间。 研究人员将光纤植入中缝背核，以及伏隔核、眶额皮质或前额叶内侧皮质。他们训练小鼠执行一项等待任务，将它们的鼻子放在一个可以“戳鼻子”的洞里，直到食物颗粒送来。在75%的试验中，研究员奖励了小鼠，在一些测试条件下，奖励时间是固定在小鼠开始戳鼻子后的6s-10s，而在其他测试条件下，奖励的时间是不同的，而剩下25%的试验中（不作为试验），研究员未给小鼠奖励。研究员测量了不作为试验中，当释放血清素的神经元受到或未受到刺激时，小鼠继续“戳鼻子”的时间，即检测它们的耐心程度。 当研究人员刺激到达伏隔核的释放血清素的神经纤维时，他们发现等待时间并没有增加，这表明血清素在大脑这个区域无法调节耐心，但是当他们刺激小鼠眶额皮质和前额叶内侧皮质释放的血清素时，他们发现老鼠等待的时间会更长。然而这两种刺激有不同之处：在眶额皮层中，血清素的释放和中缝背核中血清素的激活一样有效地促进了耐心，且奖赏时间不确定时的效果比奖赏时间固定时的强；但在前额叶内侧皮层，只观察到当奖励时间变化时小鼠耐心增加，而当奖励时间固定时则没有观察到效果。 这项研究可能对未来药物的开发具有重要意义，确定大脑中血清素促进耐心的区域，为更有针对性的治疗开辟了新的道路。
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Molecular mechanism of long-term memory discovered
By studying roundworms (Caenorhabditis elegans), scientists at the University of Basel have now discovered a molecular mechanism of long-term memory that is also involved in memory loss in old age. They report on their findings in the journal Current Biology. The team led by Dr Attila Stetak, Professor Andreas Papassotiropoulos and Professor Dominique de Quervain […]
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New tests identify very early changes in Alzheimer’s disease before symptoms appear
Researchers at the University of Gothenburg in Sweden, together with their colleagues at the Barcelona Beta Research Centre in Spain, the University Medical Centre in Ljubljana, Slovenia, and the University of Paris, have found new forms of tau protein that become abnormal in the very early stages of Alzheimer’s disease before cognitive problems develop. The […]