Finger representations in primary somatosensory cortex are modulated by a vibrotactile working memory task

Abstract

It is well-established that vibrotactile stimulations elicit Blood-oxygen-level-dependent (BOLD) responses in somatotopically organized brain regions. Whether these somatotopic maps are modulated by working memory (WM) is still unknown. In our WM experiment, participants had to compare frequencies that were separated by a delay period. Vibrotactile stimuli were sequentially applied to either their right index or little finger. Using functional MRI, we investigated whether vibrotactile WM modulated neural activity in primary somatosensory (S1), an area that is known to contain individual finger representations. Our mass-univariate results revealed the well-described network of brain regions involved in WM. Interestingly, our mass-univariate results did not demonstrate S1 to be part of this network. However, when we parametrically modulated the time-binned regressors in our GLM we found that the delay activity in S1 and secondary somatosensory cortex (S2) was reflected in a U-shaped manner. Using multi-voxel pattern analysis (MVPA), an analysis technique that is more sensitive to subtle activity differences, we found finger-specific patterns of activation in the S1 hand area during the WM delay period. These results indicate that processes underlying WM modulate finger-specific representations during our discrimination task.

Investigating cortical networks from vibrotactile stimulation in young adults using independent component analysis: an fMRI study

“…Based on a previous study, vibrotactile stimulation typically involves a widespread parieto-fronto-insular network (Rabe et al, 2021). The activity in the SMN and CCN are significantly associated with the vibrotactile stimulation of the fingertips, followed by VIN, DMN, SCN and AUN.…”

“…The activation in the MFG was discovered to be one of the most common significant regions activated during vibrotactile stimulation, and the region is active during a variety range of cognitive operations (Sung et al, 2007). The associative region is the frontal region (Rabe et al, 2021).…”

“…Furthermore, the region has been shown to produce significant activity during light tactile stimulation (Hagen & Pardo, 2002). Meanwhile, activation in the PrG (Rabe et al, 2021) and PoG (Malone et al, 2019) are common during vibrotactile stimulation.…”

“…In principle, ICA identifies the haemodynamic responses regardless of the interval, duration, or magnitude within the data (Moritz et al, 2000). As the study insisted on understanding the interaction at a network level, examining the significant region at the network level was suggested to contribute to a broader understanding of human cognition (Rabe et al, 2021).…”