振动触觉频率信息的工作记忆容量及存储机制

工作记忆可以同时保存多个信息并且容量有限, 这一内在机制是工作记忆研究的重点问题。视觉和言语等研究领域都发现工作记忆能够存储多个信息单元, 但对振动触觉工作记忆是否能存储多个频率信息目前尚无相关研究。由于振动触觉频率刺激和视觉刺激具有不同的神经编码机制, 以及振动频率信息是通过躯体感觉产生的模拟的、单维的、参数化信息, 振动触觉工作记忆容量及其加工存储机制的研究也必不可少。首先, 本项目将采用新的实验范式, 探究不同的刺激呈现方式以及不同反应报告方式下, 振动触觉工作记忆的容量及其认知机制。其次, 本项目也将同时运用功能磁共振成像(fMRI)技术, 来阐述振动触觉工作记忆加工存储的神经机制。探究基于触觉频率信息的参数工作记忆容量及其神经机制是完善工作记忆模型的重要补充, 将有助于提高我们对工作记忆系统的理解, 并为视觉、听觉、触觉多模态感知觉信息的跨通道研究奠定基础。

Capacity and maintenance mechanism of vibrotactile working memory

Working memory (WM) can preserve multiple items at one time with a limited capacity is a key issue in working memory research. WM can be divided into separate sub-systems for different information, and different neural substrates are involved in these working memory systems. While visual and verbal domains of working memory are able to store multiple items, we know little about vibrotactile working memory capacity of frequency. Whether vibrotactile working memory can store more than one stimulus is an important question for the ability to compare vibrotactile working memory to visual and verbal domains of working memory systems. Vibrotactile stimulus and visual stimulus have different neural coding mechanisms, that is extensive electrophysiological recordings have shown a monotonic dependence of monkey prefrontal cortex neurons on parametric vibrotactile frequency in the vibrotactile working memory task. At the same time, vibrotactile frequency is analogy, one-dimensional and parametric information generated by somatic sensation. Therefore, it is necessary to study the capacity of vibrotactile working memory, and reveal its cognitive and neural mechanism. Previous vibrotactile working memory studies typically used the one-item delayed match-to-sample vibrotactile discrimination task: subjects are presented with a vibrotactile frequency (sample) to the fingertip, then a second frequency (probe) is delivered to the same fingertip after a delay period. This standard task is used to examine the vibrotactile working memory of single frequency, but cannot be used to examine vibrotactile working memory of multiple frequencies and its capacity.