感觉寻求的冒险易感性机制

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	感觉寻求的冒险易感性机制
其他题名	The Vulnerability of Risk Taking in Sensation Seeking
	郑亚
	2015-05
摘要	感觉寻求（sensation seeking）是指个体对多变的、新异的、复杂的和强烈的感觉和体验的寻求，以及通过采取冒险行为来获得这些体验的愿望。感觉寻求是各种冒险行为的易感因子，但是其背后的认知和神经机制还不清楚。本文以冒险行为的双系统理论为指导框架，结合行为、脑电和功能性磁共振的技术手段，比较高感觉寻求者（high sensation seekers, HSS）和低感觉寻求者（low sensationseekers, LSS）在冒险行为的两个核心成分（认知控制系统和奖赏加工系统）上的认知和神经机制，试图探索感觉寻求的冒险易感性机制。本文第一部分采用Stop-signal 任务，从执行控制和行为监控的角度，考察感觉寻求的认知控制机制。我们发现：第一，在执行控制方面，HSS 相比于LSS表现出了更强的反应启动和更弱的反应抑制。具体来说，HSS 比LSS 表现出了对Go 信号更快的反应速度、更高的额中央区Go-N2 波幅以及更强的双侧后扣带回和右侧额上回等大脑区域的激活；尽管HSS 与LSS 在行为和脑电指标上表现出了相似的反应抑制能力，但是，HSS 并未在右侧额下回和右侧额上回等抑制相关的脑区表现出显著的抑制效应。第二，行为监控方面，当抑制失败时，HSS比LSS 表现出了更弱的Stop-N2 波幅，而在右侧前扣带回、右侧眶额皮质和左侧脑岛等区域表现出了更强的大脑激活。本文第二部分采用风险决策任务，从奖赏的基本属性和加工阶段的角度，考察感觉寻求的奖赏加工机制。我们发现，在行为选择上HSS 比LSS 表现出了更强的冒险倾向。更为重要的是，这种冒险倾向在奖赏加工的不同阶段（奖赏期待和结果评价）表现出了独特的神经活动模式。在奖赏期待阶段，HSS 较之LSS在刺激前负波（stimulus-preceding negativity, SPN）以及背内侧前额叶和脑岛等区域，表现出了更弱的风险效应；在结果评价阶段，HSS 与LSS 表现出了相似的大脑激活模式，而反馈相关负波（feedback-related negativity, FRN）的结果表明，HSS 比LSS 表现出了对奖赏强度的更低敏感性。以上实验结果表明，感觉寻求过分活跃的反应启动以及对风险更弱的神经反应，在感觉寻求的冒险寻求方面扮演了重要作用，可能是感觉寻求的冒险易感因子。这些结果有望为后续的预防和干预提供重要启示。
其他摘要	Sensation seeking is defined by a strong need for varied, novel, complex, and intense stimulation and a willingness to take risks for such experience. This personality trait is a valid predictor of various risk-taking behaviors, but the cognitive and neural underpinnings of risk taking in sensation seeking remain elusive. Here, we addressed these issues by investigating the cognitive and neural mechanisms underlying cognitive control and reward processing (i.e., two core elements responsible for risk taking) in high sensation seekers (HSS) and low sensation seekers (LSS) utilizing behavioral, electroencephalogram (EEG), and functional magnetic resonance imaging (fMRI) techniques. The first part aimed to investigate executive control and performance monitoring in sensation seeking with a series of stop-signal tasks. With respect to executive control, HSS compared to LSS displayed a stronger response initiation but a reduced response inhibition. Specifically, HSS relative to LSS exhibited a faster response speed, an enhanced fronto-central N2, and stronger activation in the bilateral posterior cingulate cortex and right superior frontal gyrus for Go signal. Moreover, although HSS and LSS showed similar response inhibition in the behavioral and EEG experiments, HSS, unlike LSS, failed to display an inhibition effect in the inhibition-related areas such as the right inferior frontal gyrus and right superior frontal gyrus. With regard to performance monitoring, when response inhibition was unsuccessful, HSS relative to LSS displayed a reduced stop-N2, but enhanced activation in the right anterior cingulate, right obito-frontal cortex, and left insula. The second part aimed to examine reward properties and different reward phases in sensation seeking with a series of risky decision-making tasks. Behaviorally, HSS relative to LSS exhibited a stronger risk-taking tendency. More importantly, the risk effect on behavioral choice in sensation seeking was reflected by the neural signals from different reward phases. During reward-anticipation phase, compared to LSS, HSS displayed a reduced risk effect on the stimulus-preceding negativity (SPN) as well as in the dorsal medial frontal cortex and insula. During outcome-appraisal phase, HSS and LSS displayed similar neural patterns, but HSS relative to LSS showed a reduced sensitivity to reward magnitude as revealed by the feedback-related negativity (FRN). In sum, our results suggest that an overactive response initiation and reduced neural activities to risk play an important role in risk taking in sensation seeking, and thus constitute the vulnerable factors that result in sensation-seeking behaviors. Our findings provide important implications for intervention in sensation seeking.
学科领域	认知神经科学
关键词	感觉寻求冒险行为认知控制奖赏加工
学位类型	博士
语种	中文
学位专业	心理学
学位授予单位	中国科学院研究生院
学位授予地点	北京
文献类型	学位论文
条目标识符	http://ir.psych.ac.cn/handle/311026/19785
专题	认知与发展心理学研究室
作者单位	中国科学院心理研究所
推荐引用方式 GB/T 7714	郑亚. 感觉寻求的冒险易感性机制[D]. 北京. 中国科学院研究生院,2015.

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