NSF-BSF: Memory modification through concurrent conscious and unconscious stimulation

我们的记忆是人类基本经验的核心。从深情地回忆童年事件到记住我们把钥匙放在哪里，记忆在我们生活的各个方面都起着至关重要的作用。它为我们提供了一种认同感，保留了我们所学到的东西，并教给我们可以在未来应用的生活课程。然而，记忆也有黑暗的一面。虽然我们依赖记忆来指导我们的行为，但有时回忆痛苦的记忆会让人痛苦，重新点燃压力。其中一个最突出的例子发生在创伤后应激障碍（PTSD）中，这是一种毁灭性的情况，在这种情况下，先前的创伤记忆可能会丧失能力，并使其难以度过一天。有没有一种方法可以通过改变记忆来帮助患有创伤后应激障碍（PTSD）的人（估计有7-8%的美国人受到影响）？长期以来，心理学家一直在争论记忆是如何以及是否可以改变的，但这个问题的答案仍然是未知的。然而，最近的证据表明，看似稳定的记忆容易被修改。受神经科学研究的启发，在细胞水平上，神经元之间突触接触的弱刺激会导致突触强度的降低，一个有趣的可能性是，对过去关联的弱提醒与新信息配对，可以非常有效地修改甚至覆盖这些旧记忆。基于这一观点，该项目旨在测试一种新的记忆修改方法，该方法涉及有意识和无意识地同时呈现信息。这一猜想的基本原理是，由于无意识刺激是“弱”的，因此应该微弱地激活其神经通路，这就打开了修改这条通路上的突触连接沿着的可能性。过去的信息无意识地（弱激活）和新的信息有意识地（强激活）的组合配对被假设为建立修改过去记忆的理想条件。这个项目通过实验验证了一个假设，即同时有意识地呈现新信息和无意识地呈现旧信息将有助于修改这些旧记忆。实验参与者最初学习两个呈现的单词刺激之间的关联（AB学习）。在参与者学习了这种配对关联之后，他们将进入第二阶段，在第二阶段，他们将被要求学习原始AB对的新的修改版本，其中“A”现在与新的刺激“C”相关联。在这一阶段，参与者的每只眼睛都会看到不同的视觉信息。在一只眼睛中，参与者有意识地看到新的AC对，同时在另一只眼睛中无意识地呈现旧的（AB）信息。实验利用连续闪光抑制技术来操纵哪些图像达到意识，哪些没有。这个实验范式允许测试的假设，无意识地呈现旧的AB信息的另一只眼睛促进AC学习。 为了确定无意识呈现的信息内容是否对最终的行为记忆测试有影响，要求参与者回忆每个A项（B或C）呈现的信息。 这些实验的行为结果将解决弱激活记忆中的旧联想是否能够修改这些旧记忆的问题。这项关于记忆修正的潜在行为工具的研究有可能带来突破，帮助人们忘记适应不良的行为，减轻与痛苦事件的生动记忆相关的压力。重塑记忆的发现对我们理解记忆和社会都有深远的影响。该项目通过NSF-BSF（美国国家科学基金会-以色列两国科学基金会）合作开展联合国际活动。该奖项反映了NSF的法定使命，通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Our memories are at the heart of our basic human experience. From fondly recollecting childhood events to remembering where we left our keys, memory plays a vital role in every aspect of our lives. It provides us with a sense of identity, preserves what we have learned, and teaches us life lessons that we can apply in the future. However, there is also a dark side to memories. While we rely on our memories to guide our behavior, sometimes the recall of painful memories can be anguishing and rekindle stress. One of the most striking examples of this occurs in post-traumatic stress disorder (PTSD), a devastating condition in which a previous traumatic memory can be disabling, and make it hard to get through the day. Is there a way to help people suffering from PTSD (which affects an estimated 7-8% of Americans) by changing their memories? Psychologists have long debated how and whether memories can be changed, but the answer to this question still remains unknown. However, recent evidence indicates that seemingly stable memories are susceptible to modification. Inspired by neuroscience research showing that at the cellular level, weak stimulation of a synaptic contact between neurons can lead to a decrease in synaptic strength, an intriguing possibility is that weak reminders of past associations paired with novel information could be very effective at modifying or even overriding those older memories. Based on this insight, this project aims to test a novel method for memory modification that involves simultaneous presentation of information both consciously and unconsciously. The rationale for this conjecture is that since unconscious stimulation is ‘weak’ and hence should activate its neural pathway weakly, this opens up the possibility of modifying the synaptic connections along this pathway. A combined pairing of past information unconsciously (weak activation) and novel information consciously (strong activation) is hypothesized to set up the ideal conditions for modifying past memories. This project experimentally tests the hypothesis that concurrent conscious presentation of new information with unconscious presentation of older information will facilitate the modification of those older memories. Experiment participants initially learn associations between two presented word stimuli (AB learning). After participants have learned this paired association, they enter the second phase where they will be asked to learn new, modified versions of the original AB pairs, in which “A” is now associated with a novel stimulus “C”. In this phase, participants are presented with different visual information to each eye. In one eye, participants consciously view the new AC pairs, while simultaneously being unconsciously presented with the older (AB) information in their other eye. The experiments make use of a continuous flash suppression technique to manipulate which images reach awareness and which do not. This experimental paradigm allows testing of the hypothesis that unconsciously presenting the older AB information to the other eye facilitates AC learning. In order to determine whether the content of the information presented unconsciously has an impact on the final behavioral memory test, participants are asked to recall which information was presented with each A item (either B or C). The behavioral results from these experiments will resolve whether weakly activating old associations in memory enables modifications of those old memories. This research on potential behavioral tools for memory modification has the potential to lead to breakthroughs that could help people unlearn maladaptive behavior and alleviate the stress associated with vivid memories of painful events. Discoveries that could reshape memory will have profound implications for our understanding of memory and also for society.This project engages joint international activities through the NSF-BSF (National Science Foundation – Israel Binational Science Foundation) collaboration.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.