Oscillatory Models of Short-Term Memory

短期记忆的振荡模型

• 批准号: 9723466
• 负责人: John Lisman
• 金额: $ 27.63万
• 依托单位: Brandeis University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2001-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9723466&HistoricalAwards=false
• 关键词: Oscillatory; Models; Short; Term; Memory

9723466 Lisman The long-term goal of this project is to understand the network and cellular basis of short-term memory, the type of memory used in remembering brief lists of items such as a phone number. Psychophysical tests on humans have shown that there is a limit of about 7 items that can be stored in short-term memory. The proposed research will extend previous theoretical work showing how a single brain network can keep 7 memories active at the same time using a multiplexing scheme. This scheme is closely tied to physiological observations on brain oscillations; multiplexing is achieved by a clocking mechanism, which is apparent in brain recordings as nested oscillations in which about 7 gamma (20-80Hz) oscillations occur within a single theta (4-10Hz) cycle. Memories become serially active in sequential gamma cycles. The psychophysical analysis of human memory provides a rich quantitative data set. The goal of the proposed work is to a develop a more detailed physiological model that correctly predicts this data. The first specific aim is to provide a specific model of how memories are scanned during a recognition memory test. Computer simulation methods will be used to model brain networks in a physiologically plausible way. The second aim is to understand a surprising constancy observed by Cavanagh: the time required to scan a memory and the number of memories that can be held both vary with the complexity of the memory; however the product of the two appears to be a universal constant. The third aim is to understand whether there are fundamental network constraints that limit how fast gamma oscillations can be; if they were faster, more memories could be held, but there may be reasons why gamma cannot be faster. Preliminary results related to the first two aims indicate that theta oscillation frequency may decrease as the number of stored memories increases. Furthermore, gamma frequency may decrease as the complexity of stored items increases. These are important findings because they provide a way of relating easily manipulatable aspects of short term memory to brain signals and because they are very testable. As the fourth goal of this proposal, collaborative efforts will be initiated to test these predictions.

小行星9723466 这个项目的长期目标是了解短期记忆的网络和细胞基础，这种记忆用于记住简短的项目列表，如电话号码。对人类的心理物理学测试表明，短期记忆中可以存储的项目限制在7个左右。这项研究将扩展以前的理论工作，展示一个单一的大脑网络如何使用多路复用方案同时保持7个记忆活跃。这个方案与脑振荡的生理学观察密切相关;多路复用是通过时钟机制实现的，这在脑记录中是明显的，作为嵌套振荡，其中约7个伽马（20- 80 Hz）振荡发生在单个θ（4- 10 Hz）周期内。存储器在连续的伽马周期中变得连续活跃。人类记忆的心理物理学分析提供了丰富的定量数据集。 拟议工作的目标是开发一个更详细的生理模型，正确预测这些数据。第一个具体的目标是提供一个具体的模型，记忆是如何扫描在识别记忆测试。 计算机模拟方法将被用来模拟大脑网络在生理上合理的方式。第二个目的是理解卡瓦纳观察到的一个令人惊讶的恒定性：扫描记忆所需的时间和可以保存的记忆数量都随记忆的复杂性而变化;然而，两者的乘积似乎是一个普适常数。第三个目标是了解是否存在基本的网络约束，限制了伽马振荡的速度;如果它们更快，就可以保存更多的记忆，但伽马振荡不能更快可能有原因。与前两个目标相关的初步结果表明，θ振荡频率可能会随着存储记忆数量的增加而降低。此外，伽马频率可以随着所存储的项目的复杂性增加而降低。 这些都是重要的发现，因为它们提供了一种将短期记忆中容易操作的方面与大脑信号联系起来的方法，而且它们非常容易测试。作为本提案的第四个目标，将开展协作努力，以检验这些预测。