Differential impact of stress on risk-taking behaviour in individuals using hippocampus versus caudate nucleus-dependent virtual navigation strategies

压力对使用海马体与尾状核依赖性虚拟导航策略的个体冒险行为的不同影响

• 批准号: RGPIN-2020-05169
• 负责人: West, Gregory
• 金额: $ 2.4万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=717192
• 关键词: Differential; impact; stress; risk; taking

Previous results from our laboratory have shown that stress has a different impact on people using the hippocampus when navigating (spatial learners) compared to those using the caudate nucleus (response learners). The hippocampus is important for spatial and episodic memory while the caudate nucleus is involved in forming habits and reward-seeking behaviour. We have previously shown that when children are exposed to a psychological stressor (i.e., being told a nurse was arriving in 30 minutes to draw blood with a needle), response learners display an increase in cortisol, a hormone released by the adrenal cortex, while spatial learners do not. Cortisol and stress have an impact on brain structures, including the hippocampus, and behaviours such as risk-taking. Further, we have shown that risk-taking behaviour as measured during a gambling task is also higher in people who are response learners. In the current grant, we will therefore investigate the neural and hormonal mechanisms by which stress has an impact on decision making, including risk-taking behavior, on these two populations and assess if spatial memory training targeting the hippocampus can mitigate risk-taking. We will first test if a psychological stressor (i.e., asking people to speak and perform a difficult math problem in front of a panel of evaluators) will cause an increase in cortisol amoungst adult response learners compared to spatial learners. We will then assess if this psychological stressor will increase risk-taking behaviour in a gambling task in response learners in comparison to spatial learners. We will also correlate the magnitude of the cortisol stress response with levels of risk-taking behaviour, to better understand the relationship between these two factors. A longitudinal spatial memory training study that uniquely targets and increases volume in the hippocampus will then be conducted. We will assess if spatial memory training over 16-weeks will have the ability to reduce risk-taking behaviour and cortisol stress response in both spatial and response learners, and test is one population preferentially benefits from such training. We will also collect structural magnetic resonance imaging scans before and after training to evaluate increases in hippocampal grey matter, and correlate this measure with changes in risk-taking behaviour. This grant will be fundamental to understand the basic neural and hormonal mechanisms involved in the interplay between competing multiple memory systems that have a direct impact on decision making. We will also be able to further evaluate if experience-dependent training can positively impact these neural mechanisms. This basic research can eventually lead to specific cognitive interventions that could benefit the cognitive health of Canadians at all stages of life, through further bridging the rodent and human literatures on the role of stress on learning and memory.

我们实验室以前的结果表明，与使用尾状核的人(反应学习者)相比，使用海马体导航的人(空间学习者)受到的压力影响不同。海马体对空间记忆和情景记忆很重要，而尾状核则参与习性和奖赏行为的形成。我们之前已经证明，当孩子们接触到心理压力(即被告知护士将在30分钟后到达用针头抽血)时，反应型学习者的皮质醇会增加，而空间学习者则不会。皮质醇是一种由肾上腺皮质释放的激素。皮质醇和压力会影响大脑结构，包括海马体，以及冒险等行为。此外，我们已经表明，在赌博任务中测量的冒险行为在学习反应的人中也更高。因此，在目前的拨款中，我们将研究压力对这两个群体的决策包括冒险行为产生影响的神经和激素机制，并评估针对海马体的空间记忆训练是否可以减少冒险行为。 我们将首先测试心理压力(即，要求人们在评估者面前说出并完成一道难的数学问题)是否会导致成年反应学习者与空间学习者相比皮质醇水平的增加。然后，我们将评估与空间学习者相比，这种心理应激源是否会在赌博任务中增加学习者的冒险行为。我们还将把皮质醇应激反应的大小与冒险行为的水平联系起来，以更好地理解这两个因素之间的关系。 然后，将进行一项专门针对海马体并增加体积的纵向空间记忆训练研究。我们将评估超过16周的空间记忆训练是否有能力减少空间和反应学习者的冒险行为和皮质醇应激反应，测试是一种优先从这种训练中受益的人群。我们还将收集训练前后的结构磁共振成像扫描，以评估海马灰质的增加，并将这一测量与冒险行为的变化联系起来。 这笔拨款将是理解基本的神经和激素机制的基础，这些机制涉及竞争的多个记忆系统之间的相互作用，这些系统对决策有直接影响。我们还将能够进一步评估依赖经验的训练是否能对这些神经机制产生积极影响。这项基础研究最终可以得出具体的认知干预措施，通过进一步联系啮齿动物和人类关于压力对学习和记忆的作用的文献，使加拿大人在人生各个阶段的认知健康受益。