振动触觉频率信息的工作记忆容量及存储机制 postprint

Abstract: 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. This study intends to explore the capacity of vibrotactile working memory and how parametric vibrotactile frequency is stored and processed in vibrotactile working memory. Although previous studies provided evidence suggestive of a multi-item storage capacity for working memory processing of vibrotactile frequency, the capacity has not yet been measured for vibrotactile frequency. First of all, different modes of vibratory stimulus presentation and response were used to determine the size of the vibrotactile working memory capacity and its cognitive mechanism. In this study, two basic forms of stimuli presentation were used to test capacity and processing of vibrotactile working memory, i.e., simultaneous and sequential presentation. Then using functional magnetic resonance imaging (fMRI), we will investigate the neural mechanism of maintenance of vibrotactile working memory. The study of vibrotactile parametric working memory is an important part of working memory model, which will contribute to our understanding of working memory system and lay a foundation for cross-modalities research of visual, auditory and tactile information.