A Biological Framework of Reduced Physical and Social Activity across the Lifespan

几十年来，我们已经知道，身体和社会活动可以有重大的健康益处，包括预防晚年健康不良和改善生病时的症状。尽管有这些好处，但许多人不定期锻炼，也不参与社会活动。随着人们年龄的增长，这种不活动的情况会增加，这给世界各地的卫生系统带来了巨大的成本，也给个人带来了重大的个人成本。阻碍积极生活的一个关键因素是动机。更有动力的人更活跃。即使是健康的人也会有很高的动机问题，比如社交冷漠（人们喜欢社交，但根本没有参与社交的意愿）或疲劳（人们在少量运动后感到疲惫）。此外，这些动机障碍随着人们年龄的增长而增加。然而，我们对为什么人们的动机不同知之甚少。是否存在社会冷漠和疲劳的生物学现象？这项研究的总体目标是确定大脑中某些系统工作方式的差异如何与社交冷漠或疲劳的人的差异有关，并研究大脑的变化如何导致随着年龄的增长而减少的动机。为了做到这一点，我将扩展基础神经科学的最新进展，这些进展提供了对大脑如何激发行为的丰富理解。在这项研究中，有人认为，动机降低可能是由于对努力行动的敏感性提高。更有动力的人发现同样的行为不那么费力。在这里，我建议研究如何不同方面的努力敏感性可能与疲劳和社会冷漠的健康人，因为他们变老。为了做到这一点，我将在健康的人类志愿者中进行研究，使用多种技术，包括大脑成像，大脑刺激和移动的电话游戏，并使用精确的计算方法量化努力敏感性。综合运用所有这些方法，我将能够回答关于大脑中在社交场合和筋疲力尽时激发行为的系统的具体问题。通过比较年轻人和老年人的努力敏感性背后的大脑系统，我将试图了解大脑中的哪些变化可能导致人们随着年龄的增长而变得更加冷漠和疲劳。总之，拟议的研究将研究的关键问题是：1）社会冷漠和疲劳是否可以表征为健康人对不同方面努力的敏感性增加？2)社会冷漠和疲劳会因为努力敏感度的提高而在整个生命周期中增加吗？3)大脑中的哪些系统是努力敏感性不同方面的基础，它们与社会冷漠和疲劳有关吗？4)老年人这些大脑系统的变化是否与努力敏感性增加、社会冷漠和疲劳有关？5)在一个独特的样本中，将脑深部刺激器植入特定的大脑区域，刺激这些大脑区域，是否可以提供这些区域与努力敏感性有因果关系的证据？这项工作将在牛津大学实验心理学系进行。主要研究者（Apps博士）将与一名博士后研究员、纳菲尔德外科科学系的顾问外科医生、维康综合神经科学信托中心和一家移动的大脑训练公司合作。

For decades, we have known that being physically and socially active can have major health benefits, including the prevention of later life ill-health and the improvement of symptoms when sick. Despite these benefits, many people do not engage in regular exercise and are socially dis-engaged. Such inactivity increases as people get older, leading to significant costs to health systems across the world, as well as major personal costs to the individual.Why aren't people more active? A crucial factor that prevents an active life is motivation. People who are more motivated are more active. Even otherwise healthy people can suffer from high levels of motivation problems such as social apathy (people enjoy social interactions but simply don't have the will to engage in them) or fatigue (people who feeling exhausted after small levels of exertion). Moreover these motivational impairments increase as people get older. Yet, we understand very little about why people vary in motivation. Is there a biology of social apathy and fatigue? The overarching aim of the proposed research is to identify how differences in how certain systems in the brain work, relates to differences in how socially apathetic or fatigued people are, and to examine how changes in the brain lead to reduced motivation as we get older. To do this I will extend recent advancements in basic neuroscience that has provided a rich understanding of how the brain motivates behaviour. Within this research it has been suggested that reduced motivation might be due to a heightened sensitivity to how effortful actions are. People who are more motivated find the same actions less effortful. Here, I propose to examine how different aspects of effort sensitivity may be linked to fatigue and social apathy in healthy people as they get older. To do this, I will perform studies in healthy human volunteers using a number of techniques including brain imaging, brain stimulation and a mobile phone game, with effort sensitivity quantified using precise computational approaches. Using all of these approaches together I will be able to answer specific questions about the systems in the brain that motivate behaviour in social situations and when getting exhausted. By comparing the brain systems underlying effort sensitivity in young and older people, I will try and understand what changes in the brain may lead to higher levels of social apathy and fatigue as people get older. In summary, the key questions that the proposed research would examine are:1) Can social apathy and fatigue be characterised as increased sensitivity to different aspects of effort in healthy people? 2) Do social apathy and fatigue increase across the lifespan because of heightened effort sensitivity? 3) What systems in the brain underlie different aspects of effort sensitivity and are they linked to social apathy and fatigue? 4) Are changes in these brain systems in older adults linked to increased effort sensitivity, social apathy and fatigue? 5) Can stimulating these brain areas in a unique sample of individuals with deep brain stimulators implanted into specific brain areas provide evidence of these regions being causally involved in effort sensitivity? This work will be carried out in the Department of Experimental Psychology, at the University of Oxford. The principal investigator (Dr. Apps) will work in collaboration with a postdoctoral researcher, consultant surgeons in the Nuffield Department of Surgical Science, the Wellcome trust Centre for integrated neuroscience and a mobile brain training company.