The hippocampal film-editor: sensitivity and specificity to event boundaries in continuous experience
The hippocampal film-editor: sensitivity and specificity to event boundaries in continuous experience
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海马电影剪辑师：连续体验中对事件边界的敏感性和特异性
DOI：
10.1101/273409
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Ben-Yakov A
中科院分区：
文献类型：
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作者：
Ben-Yakov A
人类海马体的功能通常通过离散事件的实验操作来研究。在更自然、更连续的体验中，是什么触发了海马体的活动，人们对此知之甚少。我们假设海马会对事件边界的发生很敏感，也就是说，观察者认为事件之间的过渡时刻。为了解决这个问题，我们分析了两组功能性MRI数据：一组（n= 253，131名女性）观看了8.5分钟的电影，另一组（n= 15，6名女性）观看了120分钟的电影。我们观察到一个强大的海马反应在边界定义的独立观察者，这是调制的边界显着性（观察员的数量，确定每个边界）。在较长的电影中，有足够的边界表明，这种调制在协变出大量感知因素后仍然存在。这种假设驱动的方法得到了数据驱动方法的补充，在该方法中，我们将海马事件确定为具有最强海马活动的时刻。这些海马事件和事件边界之间的对应关系是非常显着的，揭示了海马反应不仅是敏感的，而且是特定的事件边界。我们的结论是，事件边界在塑造海马活动编码的naturalistic events.Significance StatementRecently几年来，已经看到了人类神经科学研究领域从简单的刺激实验过渡到研究更复杂和自然的经验。尽管如此，我们对许多大脑区域（如海马体）功能的理解，主要是基于对短暂、离散事件的研究。因此，当我们暴露在连续的信息流中时，我们对现实生活中触发海马活动的因素知之甚少。在自然主义经验的编码过程中，海马体什么时候“决定”做出反应？我们在这里揭示，海马活动测量功能磁共振成像在电影观看过程中是敏感的和特定的事件边界，确定一个潜在的机制，事件边界形状的经验，通过调制海马活动。
The function of the human hippocampus is normally investigated by experimental manipulation of discrete events. Less is known about what triggers hippocampal activity during more naturalistic, continuous experience. We hypothesized that the hippocampus would be sensitive to the occurrence of event boundaries, that is, moments in time identified by observers as a transition between events. To address this, we analyzed functional MRI data from two groups: one (n= 253, 131 female) who viewed an 8.5 min film and another (n= 15, 6 female) who viewed a 120 min film. We observed a strong hippocampal response at boundaries defined by independent observers, which was modulated by boundary salience (the number of observers that identified each boundary). In the longer film, there were sufficient boundaries to show that this modulation remained after covarying out a large number of perceptual factors. This hypothesis-driven approach was complemented by a data-driven approach, in which we identified hippocampal events as moments in time with the strongest hippocampal activity. The correspondence between these hippocampal events and event boundaries was highly significant, revealing that the hippocampal response is not only sensitive, but also specific to event boundaries. We conclude that event boundaries play a key role in shaping hippocampal activity during encoding of naturalistic events.SIGNIFICANCE STATEMENTRecent years have seen the field of human neuroscience research transitioning from experiments with simple stimuli to the study of more complex and naturalistic experience. Nonetheless, our understanding of the function of many brain regions, such as the hippocampus, is based primarily on the study of brief, discrete events. As a result, we know little of what triggers hippocampal activity in real-life settings when we are exposed to a continuous stream of information. When does the hippocampus “decide” to respond during the encoding of naturalistic experience? We reveal here that hippocampal activity measured by fMRI during film watching is both sensitive and specific to event boundaries, identifying a potential mechanism whereby event boundaries shape experience by modulation of hippocampal activity.