Search results for "Touch Perception"
showing 10 items of 26 documents
Detecting differences with magnetoencephalography of somatosensory processing after tactile and electrical stimuli.
2018
Abstract Background Deviant stimuli within a standard, frequent stimulus train induce a cortical somatosensory mismatch response (SMMR). The SMMR reflects the brain’s automatic mechanism for the detection of change in a somatosensory domain. It is usually elicited by electrical stimulation, which activates nerve fibers and receptors in superficial and deep skin layers, whereas tactile stimulation is closer to natural stimulation and activates uniform fiber types. We recorded SMMRs after electrical and tactile stimuli. Method 306-channel magnetoencephalography recordings were made with 16 healthy adults under two conditions: electrical (eSMMR) and tactile (tSMMR) stimulations. The SMMR proto…
Thermosensory mapping of skin wetness sensitivity across the body of young males and females at rest and following maximal incremental running
2019
Key points: Humans lack skin receptors for wetness (i.e. hygroreceptors), yet we present a remarkable wetness sensitivity. Afferent inputs from skin cold-sensitive thermoreceptors are key for sensing wetness; yet, it is unknown whether males and females differ in their wetness sensitivity across their body and whether high intensity exercise modulates this sensitivity. We mapped sensitivity to cold, neutral and warm wetness across five body regions and show that females are more sensitive to skin wetness than males, and that this difference is greater for cold than warm wetness sensitivity. We also show that a single bout of maximal exercise reduced the sensitivity to skin wetness (i.e. hyg…
Activation of Corticothalamic Layer 6 Cells Decreases Angular Tuning in Mouse Barrel Cortex.
2019
In the mouse whisker system, the contribution of L6 corticothalamic cells (L6 CT) to cortical and thalamic processing of the whisker deflection direction was investigated. A genetically defined population of L6 CT cells project to infragranular GABAergic interneurons that hyperpolarize neurons in somatosensory barrel cortex (BC). Optogenetic activation of these neurons switched BC to an adapted mode in which excitatory cells lost their angular tuning. In contrast, however, this was not the case with a general activation of inhibitory interneurons via optogenetic activation of Gad2-expressing cells. The decrease in angular tuning, when L6 CT cells were activated, was due to changes in cortic…
Behavioral and Cortical Correlates of Self-Suppression, Anticipation, and Ambivalence in Rat Tickling.
2019
The relationship between tickling, sensation, and laughter is complex. Tickling or its mere anticipation makes us laugh, but not when we self-tickle. We previously showed rat somatosensory cortex drives tickling-evoked vocalizations and now investigated self-tickle suppression and tickle anticipation. We recorded somatosensory cortex activity while tickling and touching rats and while rats touched themselves. Allo-touch and tickling evoked somatotopic cortical excitation and vocalizations. Self-touch induced wide-ranging inhibition and vocalization suppression. Self-touch also suppressed vocalizations and cortical responses evoked by allo-touch or cortical microstimulation. We suggest a glo…
Development of the whisker-to-barrel cortex system.
2018
This review provides an overview on the development of the rodent whisker-to-barrel cortex system from late embryonic stage to the end of the first postnatal month. During this period the system shows a remarkable transition from a mostly genetic-molecular driven generation of crude connectivity, providing the template for activity-dependent structural and functional maturation and plasticity, to the manifestation of a complex behavioral repertoire including social interactions. Spontaneous and sensory-evoked activity is present in neonatal barrel cortex and control the generation of the cortical architecture. Half a century after its first description by Woolsey and van der Loos the whiske…
Bodily self-relatedness in vicarious touch is reflected at early cortical processing stages.
2019
Studies have suggested that there is a strong link between the bodily self and the mechanisms underlying vicarious representations. Here, we used somatosensory ERPs to investigate the temporal dynamics of vicarious touch for stimuli that are more or less related to one's own body (human hands vs. rubber gloves). We found that vicarious touch effects were restricted to self-relatable events (human hands) at early implicit stages of somatosensory processing (P45). At later more cognitive stages of processing (late positive complex, LPC), the vicarious touch effect was stronger for self-relatable events (touch on human hands) than nonself-relatable events (touch on rubber gloves) but present f…
Is that me in the mirror? Depersonalisation modulates tactile mirroring mechanisms
2016
Our sense of self is thought to develop through sensory-motor contingencies provided, not only by observing one's own body, but also by mirroring interactions with others. This suggests that there is a strong link between mirroring mechanisms and the bodily self. The present study tested whether this link is expressed at early, implicit stages of the mirroring process or at later, more cognitive stages. We also provide, to the best of our knowledge, the first demonstration of how inter-individual differences in our sense of bodily self may affect mirroring mechanisms. We used somatosensory event-related potentials (SEPs) to investigate the temporal dynamics of mirroring highly self-related …
Path Following in Non-Visual Conditions.
2018
Path-following tasks have been investigated mostly under visual conditions, that is when subjects are able to see both the path and the tool, or limb, used for navigation. Moreover, only basic path shapes are usually adopted. In the present experiment, participants must rely exclusively on continuous, non-speech, and ecological auditory and vibrotactile cues to follow a path on a flat surface. Two different, asymmetric path shapes were tested. Participants navigated by moving their index finger over a surface sensing position and force. Results show that the different non-visual feedback modes did not affect the task's accuracy, yet they affected its speed, with vibrotactile feedback causin…
Laterality judgement and tactile acuity in patients with frozen shoulder: A cross-sectional study
2020
Abstract Background Disrupted tactile acuity and poor laterality judgement have been shown in several chronic musculoskeletal pain conditions. Whether they are impaired in people with frozen shoulder (FS) remains unknown. Objectives To determine whether there is impairment in tactile acuity and laterality judgement in subjects with FS. Methods Thirty-eight subjects with idiopathic FS and 38 sex and age-matched healthy controls were enrolled. The two-point discrimination threshold (TPDT) over the affected and unaffected shoulder of patients with FS and shoulder of healthy controls was evaluated. In addition, all participants performed a left/right judgment task (LRJT). Independent and depend…
Transcranial direct current stimulation of the motor cortex induces distinct changes in thermal and mechanical sensory percepts
2009
Abstract Objective The aim of this single-blinded, complete crossover study was to evaluate the effects of tDCS on thermal and mechanical perception, as assessed by quantitative sensory testing (QST). Methods QST was performed upon the radial part of both hands of eight healthy subjects (3 female, 5 male, 25–41 years of age). These subjects were examined before and after cathodal, anodal or sham tDCS, applied in a random order. TDCS was administered for 15 min at a 1 mA current intensity, with the active electrode placed over the left primary motor cortex and the reference electrode above the right orbit. Results After cathodal tDCS, cold detection thresholds (CDT), mechanical detection thr…