Abstract
In the primary somatosensory cortex, large-scale cortical and perceptual changes have been demonstrated following input deprivation. Recently, we found that the cortical and perceptual changes induced by repetitive somatosensory stimulation (RSS) at a finger transfer to the face. However, whether such cross-border changes are specific to the face remains elusive. Here, we investigated whether RSS-induced acuity changes at the finger can also transfer to the forearm, which is the body part represented on the other side of the hand representation. Our results confirmed the transfer of tactile learning from the stimulated finger to the lip, but no significant changes were observed at the forearm. A second experiment revealed that the same regions on the forearm exhibited improved tactile acuity when RSS was applied there, excluding the possibility of low plastic ability at the arm representation. This provides also the first evidence that RSS can be efficient on body parts other than the hand. These results suggest that RSS-induced tactile learning transfers preferentially from the hand to the face rather than to the forearm. This specificity could arise from a stronger functional connectivity between the cortical hand and face representations, reflecting a fundamental coupling between these body parts.
Highlights
It is not well-understood how cortical plasticity translates into perceptual abilities and what are its limits
The latter is supported by the SI plasticity literature, which shows that depriving the hand from its inputs can lead to plastic changes[3] and referred sensations[13] across the hand-arm boundary, which is located on the opposite side of the hand representation within the homunculus
D-prime analysis confirmed a significant gain in sensitivity after repetitive somatosensory stimulation (RSS) for the right-D2 (t(17) = −3.822, p = 0.001 < pBonf) and right-Lip (t(17) = −4.275, p = 0.001 < pBonf); while, d-prime values remained stable for the left-D2 (t(17) = 0.379, p = 0.709) and right-fArm (t(17) = 0.027, p = 0.979)
Summary
It is not well-understood how cortical plasticity translates into perceptual abilities and what are its limits. Our recent findings showed that the plasticity induced in the face representation following RSS of the finger is associated with an increased tactile acuity at the face[6,12] It remains elusive whether such cross-border changes are specific and limited to the face, suggesting a special functional relationship between the hand and the face, or whether they are related to the cortical proximity of the representations. The latter is supported by the SI plasticity literature, which shows that depriving the hand from its inputs (via deafferentation or amputation) can lead to plastic changes[3] and referred sensations[13] across the hand-arm boundary, which is located on the opposite side of the hand representation within the homunculus. To test whether the right-fArm is susceptible to RSS-induced changes, we assessed the tactile acuity of healthy participants at the right-fArm before and after RSS of the same region
Sign-in/Register to view highlights & summary 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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
