先天 or 后天？为什么一些人容易冲动？

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Nature or nurture - why do some of us see red?

University of Manchester researchers are investigating why some people remain calm in the face of life's niggles, while others 'flip' with little provocation.

Recent studies using new brain-imaging technology have discovered that a change in the brain's neurochemical activity may be related to increased impulsive aggression (when someone unexpectedly reacts violently with little provocation, as opposed to someone deliberately 'looking for trouble'). Now psychologist Angela Rylands wants to deploy the University's world-leading HRRT PET brain scanner, based at its Wolfson Molecular Imaging Centre (WMIC), as part of a project to find out more.

Angela said: \"ositron emission tomography (PET) scanning has revealed that a deficit in brain serotonin neurotransmission may leave some people more prone to aggression and impulse control disorders. I want to establish to what extent such behaviours are rooted at a molecular level and how much does learning from the environment around us also play a part.\"

One of her case studies, 39-year-old former professional bodyguard turned retail manager Carl Hayes, is available for interview. Carl is taking part in order to find out why he loses his temper so easily (he once set light to ?00 in a row with his ex-wife).

Angela is looking for other males aged 18 or over, who do not use illegal drugs, and who feel they may be impulsively aggressive to have their brains scanned, to develop the team's understanding of the processes at work. Genetic samples will also be taken to enable them to investigate any interesting polymorphisms (genetic markers which occur in different forms from person to person), as previous research has implicated specific polymorphisms in aggressive behaviour.

Angela will then carry out psychological assessments of participants' previous exposure to aggression and neuropsychological tests to assess their aggressive capacity.

\"It's well known that the prefrontal brain regions are associated with normal social and emotional behaviour, and that people with damage to these areas are more impulsive and aggressive,\" Angela continued. \"We now want to see whether subtle deficits in the brain's serotonin system can explain differing levels of aggression in people who don't have brain damage. Our first theory is that higher capacity for impulsive aggression will be found in those with the lowest levels of brain serotonin. The second is that a combination of our genetic makeup and a harsh or abusive childhood may lead to the brain serotonin system not developing normally.

\"The areas of serotonin neurotransmission that we are interested in are in the brain regions associated with inhibitory control. Of course people need to take responsibility for their own behaviour, but it could be that some people have difficulties controlling aggression because of impaired regulation of negative emotions or social behaviour by the serotonin system in their brains.

\"The genetic samples we take and our assessments of people's exposure to aggression in their childhoods may uncover the factors that adversely influence the developing serotonin system and lead to a dysfunctional system in the mature adult.

\"If we can get to the root of impulsive aggressive behaviour - be it nature, nurture or a combination of the two - it could help us to identify how we can break the cycle of impulsive and aggressive behaviour and intervene with future generations at risk from losing control.\"

She added: \"This work may prevent future generations suffering the consequences of impulsive aggression.

\"Aggression that occurs as a consequence of poor impulse control presents a burden for society. Each year over half a million people worldwide die from interpersonal violence. The financial burden of violent crime adds to this, incurring expenditures for the criminal justice system, for the incarceration of offenders and to local victims. Socioeconomic costs and public health issues persist, as a consequence of aggressive behaviour.

\"The underpinnings of aggression should be identified to enable advancement towards preventative measures.\"

Participants will visit the WMIC for a screening session, followed by a scan if appropriate. They will then undergo psychological assessments of their previous exposure to aggression, and neuropsychological tests to assess their aggressive capacity. Volunteers will be reimbursed for their time and travel expenses.

Source: University of Manchester

先天？后天？为什么一些人容易冲动？
来自曼彻斯特大学的研究者们正在研究为什么我们当中的某些人能够从容面对生活中的琐屑小事，而另外一些人却常常因为生活中的一点小事而大发雷霆。
最近，研究者利用新的脑成像技术研究发现，脑部的神经化学物质活性的变化可能跟冲动情绪相关（当某人为一点小事反应过度，好像别人是在故意找他的麻烦）。现在，心理学家Angela Rylands计划使用曼彻斯特大学Wolfson分子成像中心（WIMIC）的HRRT-PET脑部扫描仪来研究该问题，希望得到更多发现。值得一提的是该HRRT-PET脑部扫描仪为全球最先进的脑部扫描仪。
Angela表示：利用PET（正电子体层扫描术）扫描技术，已经发现脑血清素神经传递的缺陷可能导致某些人更容易冲动。下一步他们想知道的是在多大程度上该症状与遗传（分子水平）相关，在多大程度上与环境相关。
她的研究研究对象之一，39岁的前职业保镖，现零售经理Carl Hayes表示他可以接受采访。Carl正在参与该项研究，以期找到他为什么如此容易冲动的原因（他曾经和他前妻一口气烧了800英镑）。
Angela还在招募其他18岁以上的，具有冲动特点的非瘾君子来参与该项研究，以期进一步加深他们对正在研究的导致冲动的分子机理的理解。先前的研究表明冲动的行为跟某些特定的遗传标记有关，因此，他们也将收集各种遗传样本来研究他们感兴趣的多态样本（不同的人具有不同的遗传标记）。
Angela将会对有过冲动史的和接受过神经心理测试的志愿者们进行心理学鉴定来评估他们的冲动控制能力。
“众所周知，脑前头叶区域是跟正常的社交和情绪控制有关的，该部分脑有损伤的人更容易冲动”Angela接着说，“我们现在想知道对于那些脑前头叶区域正常的，但又具有不同程度冲动控制能力缺陷的人来说，他们的行为是不是可以用脑血清素系统的微小缺陷来解释。我们的第一个观点是：脑血清素水平越低的人控制冲动能力越差，第二个观点是：遗传和环境的因素（如：苦难的童年时光）共同导致了脑血清素系统发育不正常”。
“我们感兴趣的血清素神经传递区域位于和行为克制有关的脑区域。当然，人们需要对他们的行为负责，但对于某些人说他们难以控制自己的情绪是由于他们调控负面情绪的脑血清素系统的缺陷所致。”
“通过对收集的遗传样本的研究和对人们童年时受侵犯经历的分析有可能帮助我们发现对发育中的血清素系统产生负面影响和导致成人血清素系统功能不正常的原因。”
“倘若我们能够发现导致容易产生冲动行为的根源，不论是先天因素，还是后天因素，抑或是两者都有，这将有助于我们对该症状的治疗，并对有向该症状发展趋势的下一代进行干预治疗。
她提到“这项工作有可能让我们的下一代不用遭受冲动的惩罚”。
“由于冲动控制能力差导致的攻击行为对社会来说是一个沉重的负担。每年全世界因暴力而死的人超过50万。由此带来的财政负担，涉及到司法体系、监狱系统以及对受害者的补偿等。暴力行为带来的社会经济问题和公众安全问题持续不断。”
“暴力的根源必须被确定，这将有助于我们采取预防措施。
志愿者将到WIMIC进行一次初筛，合适的人选将会进行脑部扫描。然后，他们将接受关于针对受暴力侵犯方面的心理学鉴定和评估暴力倾向的神经心理测试。志愿者将获得交通补偿和一部分补助。

来源：曼彻斯特大学。