Abstract
Recent working memory (WM) research has focused on identifying brain regions that retain different types of mental content. Only few neuroimaging studies have explored the mechanism of attention‐based refreshing, which is a type of rehearsal and is thought to implement the dynamic components of WM allowing for update of WM contents. Here, we took advantage of the distinct coding properties of the superior parietal lobe (SPL), which retains spatial layout information, and the right inferior frontal gyrus (IFG), which retains frequency information of vibrotactile stimuli during tactile WM. In an fMRI delayed match‐to‐sample task, participants had to internally rehearse sequences of spatial layouts or vibratory frequencies. Our results replicate the dissociation of SPL and IFG for the retention of layout and frequency information in terms of activation differences between conditions. Additionally, we found strong premotor cortex (PMC) activation during rehearsal of either stimulus type. To explore interactions between these regions we used dynamic causal modeling and found that activation within the network was best explained by a model that allows the PMC to drive activity in the SPL and IFG during rehearsal. This effect was content‐specific, meaning that the PMC showed stronger influence on the SPL during pattern rehearsal and stronger influence on the IFG during frequency rehearsal. In line with previously established PMC contributions to sequence processing, our results suggest that it acts as a content‐independent area that flexibly recruits content‐specific regions to bring a WM item into the focus of attention during the rehearsal of tactile stimulus sequences.
Highlights
The ability to flexibly represent and manipulate mental content is a key aspect of human cognition
In a recent multivariate pattern analysis (MVPA) study, we demonstrated that spatial layout information can be decoded from activation patterns in the superior parietal lobe (SPL) when participants memorized vibrotactile stimuli similar to those used in the current study (Schmidt & Blankenburg, 2018)
Our results further support the dissociation of Working memory (WM) content representations of spatial layout and vibratory frequency in SPL and right inferior frontal gyrus (IFG), respectively
Summary
The ability to flexibly represent and manipulate mental content is a key aspect of human cognition. It allows integrating information obtained from the senses with information from long-term memory to solve complex cognitive tasks, perform reasoning, and make memorybased decisions. In attention-based refreshing, which is addressed in the current study, nonverbal, sensory-like mental material is retained, such as visual images or tactile sensations. Neuronal activity that represents mental content in these buffer systems is thought to decay over time and attention-based refreshing is thought to reactivate these neuronal ensembles and thereby act against the decay of delay activity and fading of a mental representation (Camos et al, 2018)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call