Touch Discrimination Research Articles

Is there a relationship between somatosensory impairment and the perception of pain in stroke survivors? An exploratory study.

Pain and somatosensory impairments are commonly reported following stroke. This study investigated the relationship between somatosensory impairments (touch detection, touch discrimination and proprioceptive discrimination) and the reported presence and perception of any bodily pain in stroke survivors. Stroke survivors with somatosensory impairment ( N = 45) completed the Weinstein Enhanced Sensory Test (WEST), Tactile Discrimination Test, and Wrist Position Sense Test for quantification of somatosensation in both hands and the McGill Pain Questionnaire, visual analog scale and the Neuropathic Pain Symptom Inventory (NPSI) for reporting presence and perception of pain. No relationship was observed between somatosensory impairment (affected contralesional hand) of touch detection, discriminative touch or proprioceptive discrimination with the presence or perception of pain. However, a weak to moderate negative relationship between touch detection in the affected hand (WEST) and perception of pain intensity (NPSI) was found, suggesting that stroke survivors with milder somatosensory impairment of touch detection, rather than severe loss, are likely to experience higher pain intensity [rho = -0.35; 95% confidence interval (CI), -0.60 to -0.03; P = 0.03]. Further, a moderate, negative relationship was found specifically with evoked pain (NPSI) and touch detection in the affected hand (rho = -0.43; 95% CI, -0.72 to -0.02; P = 0.03). In summary, our findings indicate a weak to moderate, albeit still uncertain, association, which prevents making a definitive conclusion. Nevertheless, our findings contribute to our understanding of the complexities surrounding the experience of pain in survivors of stroke and provide direction for future studies.

RFDrive: Tagged Human-Vehicle Interaction for All

Human–vehicle interaction is an important factor for safe driving. The driver needs to interact with the in-vehicle steering wheel and infotainment system properly during driving. Specifically, driving guidelines require the driver to hold the steering wheel at the 3 o’clock and 9 o’clock positions. Moreover, the in-vehicle infotainment system should be more adaptive for the driver and front-seat passenger during driving (i.e., the in-vehicle infotainment system should be part and even fully disabled for the driver, whereas the front-seat passenger should be able to enjoy the full in-vehicle infotainment system). However, affordable vehicles are usually designed to achieve basic driving functions without considering safe human–vehicle interactions, which require an add-on, affordable, and ready-to-use human–vehicle interaction monitoring system. In this article, we present RFDrive, a system that can simultaneously locate the driver’s hand positions on the steering wheel and automate in-vehicle infotainment system touch discrimination for safe driving using commodity passive RFID tags. Since these commodity passive RFID tags are low cost (i.e., around 5 cents per tag), battery free, and are small, like a sticker, our design will enable not only safe driving but is also low cost, which can lead to sustainable solutions. To do so, we attach RFID tags on the steering wheel for the driver’s hand position location and attach RFID tags on the roof of the vehicle’s interior for in-vehicle infotainment system touch discrimination (i.e., differentiating the driver’s infotainment system touch and front-seat passenger’s infotainment system touch). However, the wheel steering will distort the wireless channel-based driver’s hand position location on the steering wheel. Thus, we propose a novel tag ID-based algorithm to locate the driver’s hand position on the steering wheel by harnessing the human body as part of the RFID tag’s antenna. Since the in-vehicle infotainment system touch from the driver or front-seat passenger will affect different RFID tags attached to the roof of the vehicle’s interior, we propose to use the differential amplitude of backscattered signals from all the tags to discriminate in-vehicle infotainment system touch sources. Our experiments show that RFDrive can achieve the average accuracy of 0.98 and 0.98 for in-vehicle touch source discrimination and driver’s hand position location, respectively.

A case of confusion: context matters when using reference images on exams

Instructors utilize reference figures from textbooks, journals, and other sources on quizzes and exams to illustrate concepts that would otherwise be diffcult to convey using written text. Examples within biomedical teaching include anatomical images and graphs that students are expected to analyze or interpret. However, the use of a figure may cause confusion and lead students to select an incorrect answer. As such, instructors must evaluate the use of figures to ensure that they enhance students’ ability to correctly answer the question rather than hinder it. This report shows an example where the inclusion of a reference figure led to the majority of students incorrectly answering a question.Over 6 semesters in a master’s level graduate neuroscience course between 2019 and 2021, the same question was used with and without a reference figure in a variety of contexts to determine the factors that contributed to students overwhelmingly selecting an incorrect answer. In the question, students were asked to identify neuroarchitectural adaptations in the somatosensory cortex following amputation. To determine the correct answer, students needed to integrate knowledge of the discriminative touch sensory pathways with knowledge of cortical plasticity.In semesters where the figure was presented without specific teaching interventions, 57% of students selected an incorrect answer that utilized the proximity of cortical sites but was not supported by the signaling pathways. In these semesters, only 39% of students correctly answered. In semesters where the figure was not used, 94% of students correctly answered the question while only 6% of students selected the most common incorrect answer when the figure was present.Teaching interventions were introduced during two semesters in an attempt to “teach the question.” Students were asked to read primary literature on the topic, additional examples and cases were introduced, and in one semester, a similar practice question using was given to the students. Students were then presented with the question containing the image. 56% of students selected the most common incorrect answer while only 42% of students correctly answered the question.While no formal survey of the students was conducted, anecdotal evidence from student offce hours, directed inquiries, and casual conversations indicate that students generally felt that use of the figure, when present, was critical to answering the question and many reported that using the figure led them to prioritize their knowledge of cortical plastic adaptations over that of the signaling pathways.These results demonstrate the importance of carefully utilizing reference images on questions for quizzes and exams. The visual cues of the image can be powerful stimuli for students when analyzing the information and can sometimes lead to incorrect answers on the assessment. This work was supported by internal funding from the Georgetown University Graduate School of Biomedical Sciences and Georgetown University Medical Center’s Center for Innovation and Leadership in Education (CENTILE). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Evolutionarily conserved neural responses to affective touch in monkeys transcend consciousness and change with age

Affective touch-a slow, gentle, and pleasant form of touch-activates a different neural network than which is activated during discriminative touch in humans. Affective touch perception is enabled by specialized low-threshold mechanoreceptors in the skin with unmyelinated fibers called C tactile (CT) afferents. These CT afferents are conserved across mammalian species, including macaque monkeys. However, it is unknown whether the neural representation of affective touch is the same across species and whether affective touch's capacity to activate the hubs of the brain that compute socioaffective information requires conscious perception. Here, we used functional MRI to assess the preferential activation of neural hubs by slow (affective) vs. fast (discriminative) touch in anesthetized rhesus monkeys (Macaca mulatta). The insula, anterior cingulate cortex (ACC), amygdala, and secondary somatosensory cortex were all significantly more active during slow touch relative to fast touch, suggesting homologous activation of the interoceptive-allostatic network across primate species during affective touch. Further, we found that neural responses to affective vs. discriminative touch in the insula and ACC (the primary cortical hubs for interoceptive processing) changed significantly with age. Insula and ACC in younger animals differentiated between slow and fast touch, while activity was comparable between conditions for aged monkeys (equivalent to >70 y in humans). These results, together with prior studies establishing conserved peripheral nervous system mechanisms of affective touch transduction, suggest that neural responses to affective touch are evolutionarily conserved in monkeys, significantly impacted in old age, and do not necessitate conscious experience of touch.

Identifying Correlated Functional Brain Network Patterns Associated with Touch Discrimination in Survivors of Stroke Using Automated Machine Learning

Stroke recovery is multifaceted and complex. Machine learning approaches have potential to identify patterns of brain activity associated with clinical outcomes, providing new insights into recovery. We aim to use machine learning to characterise the contribution of and potential interaction between resting state functional connectivity networks in predicting touch discrimination outcomes in a well-phenotyped, but small, stroke cohort. We interrogated and compared a suite of automated machine learning approaches to identify patterns of brain activity associated with clinical outcomes. Using feature reduction, the identification of combined ‘golden features’, and five-fold cross-validation, two golden features patterns emerged. These golden features identified patterns of resting state connectivity involving interactive relationships: 1. The difference between right insula and right superior temporal lobe correlation and left cerebellum and vermis correlation; 2. The ratio between right inferior temporal lobe and left cerebellum correlation and left frontal inferior operculum and left supplementary motor area correlation. Our findings demonstrate evidence of the potential for automated machine learning to provide new insights into brain network patterns and their interactions associated with the prediction of quantitative touch discrimination outcomes, through the automated identification of robust associations and golden feature brain patterns, even in a small cohort of stroke survivors.

A BIONIC HAND VS. A REPLANTED HAND.

Evaluation of the hand function affected when replacing a malfunctioning hand by a bionic hand. Case report. One individual that wished for a better quality of life after unsatisfying hand function following a replantation. A quantitative and qualitative evaluation of body functions as well as activity performance and participation before and after a planned amputation and prosthetic fitting is presented. Improvements were seen in the patient-reported outcome measures (PROMs) that were used regarding activity (Disability of the Arm, Shoulder and Hand [DASH] and Canadian Occupational Performance Measure [COPM]), pain (Neuropathic Pain Symptom Inventory [NPSI], Brief Pain Inventory [BPI], Visual Analogue Scale [VAS]), cold intolerance (CISS) and health related quality of life (SF-36), as well as in the standardised grip function test, Southampton Hand Assessment Procedure (SHAP). No referred sensations were seen but the discriminative touch on the forearm was improved. In the qualitative interview, a relief of pain, a lack of cold intolerance, improved appearance, better grip function and overall emotional wellbeing were expressed. The planned amputation and subsequent fitting and usage of a hand prosthesis were satisfying for the individual with positive effects on activity and participation. When the hand function after a hand replantation does not reach satisfactory levels, a planned amputation and a prosthetic hand can be the right solution.

Oscillatory Responses to Tactile Stimuli of Different Intensity.

Tactile perception encompasses several submodalities that are realized with distinct sensory subsystems. The processing of those submodalities and their interactions remains understudied. We developed a paradigm consisting of three types of touch tuned in terms of their force and velocity for different submodalities: discriminative touch (haptics), affective touch (C-tactile touch), and knismesis (alerting tickle). Touch was delivered with a high-precision robotic rotary touch stimulation device. A total of 39 healthy individuals participated in the study. EEG cluster analysis revealed a decrease in alpha and beta range (mu-rhythm) as well as theta and delta increase most pronounced to the most salient and fastest type of stimulation. The participants confirmed that slower stimuli targeted to affective touch low-threshold receptors were the most pleasant ones, and less intense stimuli aimed at knismesis were indeed the most ticklish ones, but those sensations did not form an EEG cluster, probably implying their processing involves deeper brain structures that are less accessible with EEG.

Middle superior and anterior superior alveolar nerve injury following trauma to the maxillary sinus: a prospective clinico-radiographic evaluation.

Anterior maxillary sinus wall fractures are common in all types of maxillofacial trauma. They can result in various complications, including injury to the surrounding nerves. Owing to its anatomy, trauma to the maxillary antrum can result in injury to the middle superior alveolar nerve (MSAN) and the anterior superior alveolar nerve (ASAN). The purpose of this study is to evaluate neurosensory deficits (NSD) present in maxillary gingiva, incisors, and premolars after injury to the anterior wall of the maxillary antrum. This prospective study was conducted among 39 patients sustaining unilateral fractures of the anterior maxillary sinus wall. Clinical neurosensory tests including two-point discrimination and fine touch discrimination were performed to classify the extent of nerve injuries as mild, moderate, severe, or anesthetic. Additional temperature discrimination and pulpal sensibility tests (electric pulp testing and cold testing) were carried out. A comparison of radiographic fracture patterns and severity of nerve injury was done. Testing was carried out immediately after trauma and at 2-month follow-up. More than half of the patients assessed in the study group presented with NSD of the teeth and gingiva after trauma. The incidence of deficits varied with the type of test used to measure them. Most frequently, patients presented with both loss of two point as well as fine touch discrimination thresholds. Severe nerve injuries were associated with loss of temperature discrimination clinically and displaced fractures radiographically. There was no significant relationship between the recovery of pulpal and gingival sensation. The patterns of injury and recovery in ASAN and MSAN were similar. NSD after trauma to the maxillary antrum is relatively common. Clinical loss of temperature discrimination and radiographic signs of fracture lines passing through the canalis sinuosus are predictors of persistent and severe oral NSD.

The neural correlates of texture perception: A systematic review and activation likelihood estimation meta-analysis of functional magnetic resonance imaging studies.

Humans use discriminative touch to perceive texture through dynamic interactions with surfaces, activating low-threshold mechanoreceptors in the skin. It was largely assumed that texture was processed in primary somatosensory regions in the brain; however, imaging studies indicate heterogeneous patterns of brain activity associated with texture processing. To address this, we conducted a coordinate-based activation likelihood estimation meta-analysis of 13 functional magnetic resonance imaging studies (comprising 15 experiments contributing 228 participants and 275 foci) selected by a systematic review. Concordant activations for texture perception occurred in the left primary somatosensory and motor regions, with bilateral activations in the secondary somatosensory, posterior insula, and premotor and supplementary motor cortices. We also evaluated differences between studies that compared touch processing to non-haptic control (e.g., rest or visual control) or those that used haptic control (e.g., shape or orientation perception) to specifically investigate texture encoding. Studies employing a haptic control revealed concordance for texture processing only in the left secondary somatosensory cortex. Contrast analyses demonstrated greater concordance of activations in the left primary somatosensory regions and inferior parietal cortex for studies with a non-haptic control, compared to experiments accounting for other haptic aspects. These findings suggest that texture processing may recruit higher order integrative structures, and the secondary somatosensory cortex may play a key role in encoding textural properties. The present study provides unique insight into the neural correlates of texture-related processing by assessing the influence of non-textural haptic elements and identifies opportunities for a future research design to understand the neural processing of texture.

The perception of pain, discriminative touch and affective touch in patients suffering from Borderline Personality Disorder

Borderline Personality Disorder (BPD) is often characterized by self-injurious behaviors, with one-half to two-third of these patients reporting hypalgesic or analgesic phenomena during self-harming. Research on pain perception in BPD suggested abnormal processing of nociception either within the sensory-discriminative and/or motivational-affective systems of pain. Nevertheless, it is still unclear whether pain insensitivity could be generalized to other somatosensory submodalities. To investigate this question, 30 BPD patients and 30 matched healthy controls were enrolled in the current study and underwent a somatosensory battery composed of well-established psychophysical test assessing all the principal submodalities of somatosensation, namely pain perception (i.e., warm, cold and mechanical), discriminative touch (i.e., tactile acuity and tactile sensitivity) as well as affective touch. Results showed abnormal warm detection threshold, warm pain threshold, mechanical pain perception, and tactile sensitivity in BPD patients, but no differences emerged neither for tactile acuity nor for cold pain thresholds, cold tolerance, or for affective touch perception. Findings point to a deficit in nociception, as well as in tactile sensitivity in BPD individuals, and were discussed in relation to BPD clinical features including self-injurious behaviors.

Social Touch: Its Mirror-like Responses and Implications in Neurological and Psychiatric Diseases.

What is the significance of a touch encoded by slow-conducted unmyelinated C-tactile (CT) fibers? It is the so-called affiliative touch, which has a fundamental social impact. In humans, it has been demonstrated that the affiliative valence of this kind of touch is encoded by a dedicated central network, not involved in the encoding of discriminative touch, namely, the "social brain". Moreover, CT-related touch has significant consequences on the human autonomic system, not present in the case of discriminative touch, which does not involve CT fibers as the modulation of vagal tone. In addition, CT-related touch provokes central effects as well. An interesting finding is that CT-related touch can elicit "mirror-like responses" since there is evidence that we would have the same perception of a caress regardless of whether it would be felt or seen and that the same brain areas would be activated. Information from CT afferents in the posterior insular cortex likely provides a basis for encoding observed caresses. We also explored the application of this kind of touch in unphysiological conditions and in premature newborns. In the present literature review, we aim to (1) examine the effects of CT-related touch at autonomic and central levels and (2) highlight CT-related touch and mirror networks, seeking to draw a line of connection between them. Finally, the review aims to give an overview of the involvement of the CT system in some neurologic and psychiatric diseases.

Characterizing Touch Discrimination Impairment from Pooled Stroke Samples Using the Tactile Discrimination Test: Updated Criteria for Interpretation and Brief Test Version for Use in Clinical Practice Settings.

Somatosensory loss post-stroke is common, with touch sensation characteristically impaired. Yet, quantitative, standardized measures of touch discrimination available for clinical use are currently limited. We aimed to characterize touch impairment and re-establish the criterion of abnormality of the Tactile Discrimination Test (TDT) using pooled data and to determine the sensitivity and specificity of briefer test versions. Baseline data from stroke survivors (n = 207) and older neurologically healthy controls (n = 100) assessed on the TDT was extracted. Scores were re-analyzed to determine an updated criterion of impairment and the ability of brief test versions to detect impairment. Updated scoring using an area score was used to calculate the TDT percent maximum area (PMA) score. Touch impairment was common for the contralesional hand (83%) but also present in the ipsilesional hand (42%). The criterion of abnormality was established as 73.1 PMA across older adults and genders. High sensitivity and specificity were found for briefer versions of the TDT (25 vs. 50 trials; 12 or 15 vs. 25 trials), with sensitivity ranging between 91.8 and 96.4% and specificity between 72.5 and 95.0%. Conclusion: Updated criterion of abnormality and the high sensitivity and specificity of brief test versions support the use of the TDT in clinical practice settings.

The perception of affective and discriminative touch in blind individuals

Enhanced tactile acuity in blindness is among the most widely reported results of neuroplasticity following prolonged visual deprivation. However, tactile submodalities other than discriminative touch are profoundly understudied in blind individuals. Here, we examined the influence of blindness on two tactile submodalities, affective and discriminative touch, the former being vital for social functioning and emotional processing. We tested 36 blind individuals and 36 age- and sex-matched sighted volunteers. In Experiment 1, we measured the perception of affective tactile signals by asking participants to rate the pleasantness of touch delivered on the palm (nonhairy skin, sparsely innervated with C tactile [CT] fibers) or the forearm (hairy skin, densely innervated with CT fibers) in a CT-optimal versus a CT-nonoptimal manner using a paradigm grounded in studies on tactile sensory neurophysiology. In Experiment 2, we implemented a classic task assessing discriminative touch abilities, the grating orientation task. We found that blind individuals rated the touch as more pleasant when delivered on the palm than on the forearm, while the opposite pattern was observed for sighted participants, who rated stimulation on the forearm as more pleasant than stimulation on the palm. We also replicated the previous findings showing enhanced discriminative tactile acuity in blind individuals. Altogether, our results suggest that blind individuals might experience affective touch differently than sighted individuals, with relatively greater pleasantness perceived on the palm. These results provide a broader insight into somatosensory perception in blind individuals, for the first time taking into consideration the socioemotional aspect of touch.

Eicosapentaenoic acid enhances PIEZO2 inactivation and counteracts PIEZO2 gain of function mutations.

PIEZO2 is an essential mechanosensitive ion channel for touch discrimination, vibration, interoception, and proprioception. Mechanosensitive ion channels rely on membrane composition to transduce physical stimuli into electrical signals. Dietary fatty acids are among the membrane lipid components that dynamically regulate ion channel function. We have previously shown that when part of the plasma membrane, the polyunsaturated fatty acid (PUFA) eicosapentaenoic acid (C20:5, EPA) decreases membrane rigidity and bending stiffness, while enhancing PIEZO1 inactivation. To determine if EPA could also modulate PIEZO2 channel function, we used electrophysiology, fatty acid supplementation, dietary intervention, and lipidomics in vitro and ex vivo. We found that EPA, when incorporated into the membrane, increased the inactivation of heterologously expressed PIEZO2 without significantly affecting the current magnitude or apparent activation threshold. Similarly, we measured an increase in PIEZO2 inactivation in rat and mouse dorsal root ganglia (DRG) neurons after EPA supplementation. Importantly, cultured DRG neurons from mice carrying the C. elegans FAT-1 enzyme (which converts ω-6 to ω-3 PUFAs) or fed for 4-12 weeks with an EPA-enriched diet displayed enhanced PIEZO2 inactivation when compared to neurons from control mice. Moreover, using a consecutive mechanical step protocol, we found that PIEZO2 slowly recovered from inactivation in DRG neurons supplemented with EPA, from fat-1 mice, or from mice fed with an EPA-enriched diet, when compared with the control. These results support the notion that EPA favors PIEZO2 non-conductive states. Gain-of-function PIEZO2 mutations causing Distal Arthrogryposis type 5 display decreased PIEZO2 inactivation and enhanced recovery from inactivation. We show that EPA supplementation restored the gating properties of Distal Arthrogryposis causing mutations to wild-type levels in vitro. Overall, our findings show that dietary fatty acids modulate PIEZO2 function and could be an effective strategy to ameliorate GOF PIEZO2-mediated diseases.

Affective touch in the context of development, oxytocin signaling, and autism.

Touch represents one of our most important senses throughout life and particularly in the context of our social and emotional experiences. In this review, we draw on research on touch processing from both animal models and humans. Firstly, we briefly describe the cutaneous touch receptors and neural processing of both affective and discriminative touch. We then outline how our sense of touch develops and summarize increasing evidence demonstrating how essential early tactile stimulation is for the development of brain and behavior, with a particular focus on effects of tactile stimulation in infant animals and pediatric massage and Kangaroo care in human infants. Next, the potential mechanisms whereby early tactile stimulation influences both brain and behavioral development are discussed, focusing on its ability to promote neural plasticity changes and brain interhemispheric communication, development of social behavior and bonding, and reward sensitivity through modulation of growth factor, oxytocin, and opioid signaling. Finally, we consider the implications of evidence for atypical responses to touch in neurodevelopmental disorders such as autism spectrum disorder and discuss existing evidence and future priorities for establishing potential beneficial effects of interventions using massage or pharmacological treatments targeting oxytocin or other neurochemical systems.

The encoding of touch by somatotopically aligned dorsal column subdivisions

The somatosensory system decodes a range of tactile stimuli to generate a coherent sense of touch. Discriminative touch of the body depends on signals conveyed from peripheral mechanoreceptors to the brain through the spinal cord dorsal column and its brainstem target, the dorsal column nuclei (DCN)1,2. Models of somatosensation emphasize that fast-conducting low-threshold mechanoreceptors (LTMRs) innervating the skin drive the DCN3,4. However, postsynaptic dorsal column (PSDC) neurons within the spinal cord dorsal horn also collect mechanoreceptor signals and form a second major input to the DCN5–7. The significance of PSDC neurons and their contributions to the coding of touch have remained unclear since their discovery. Here we show that direct LTMR input to the DCN conveys vibrotactile stimuli with high temporal precision. Conversely, PSDC neurons primarily encode touch onset and the intensity of sustained contact into the high-force range. LTMR and PSDC signals topographically realign in the DCN to preserve precise spatial detail. Different DCN neuron subtypes have specialized responses that are generated by distinct combinations of LTMR and PSDC inputs. Thus, LTMR and PSDC subdivisions of the dorsal column encode different tactile features and differentially converge in the DCN to generate specific ascending sensory processing streams.

Standardized Quantitative Sensory Testing to Assess Insufficient Recovery of Touch Discrimination in Free Flap Surgery.

With major advances in microsurgical techniques, free tissue transfer has become a widely adopted approach to treat complex soft-tissue defects. However, sensory recovery is poor, leaving the anesthetic skin prone to injuries. Twenty-eight patients with 22 anterior lateral thigh flaps and six latissimus dorsi flaps on their extremities participated in the study. Quantitative sensory testing and two-point discrimination was performed in three test areas and one control on the contralateral unaffected extremity. Physical disability, mental health, quality of life, and characteristics of pain were assessed by the painDetect, Disabilities of the Arm, Shoulder, and Hand, Lower Extremity Functional Scale, and 12-Item Short Form questionnaires, respectively. Somatosensory profiles of all flaps were characterized by an overall loss of nerve function. Small-fiber function was mostly recovered, whereas large-fiber function, and thus touch discrimination, was severely impaired. Mechanical detection thresholds improved over time and from center to the periphery. Reported pain was mild to moderate and correlated with decreased physical function. Standardized quantitative sensory testing provides a useful tool kit to assess the sensory regeneration after surgical treatment of soft-tissue defects. After free tissue transfer, small-fiber function recovers with nerve ingrowth in a centripetal direction from the flap margins to the center, likely by way of collateral axonal sprouting from the undamaged nerves surrounding the flap. Myelinated fibers recover slowly and inefficiently. Therapeutic, IV.

The importance of visual control and biomechanics in the regulation of gesture-speech synchrony for an individual deprived of proprioceptive feedback of body position.

Do communicative actions such as gestures fundamentally differ in their control mechanisms from other actions? Evidence for such fundamental differences comes from a classic gesture-speech coordination experiment performed with a person (IW) with deafferentation (McNeill, 2005). Although IW has lost both his primary source of information about body position (i.e., proprioception) and discriminative touch from the neck down, his gesture-speech coordination has been reported to be largely unaffected, even if his vision is blocked. This is surprising because, without vision, his object-directed actions almost completely break down. We examine the hypothesis that IW’s gesture-speech coordination is supported by the biomechanical effects of gesturing on head posture and speech. We find that when vision is blocked, there are micro-scale increases in gesture-speech timing variability, consistent with IW’s reported experience that gesturing is difficult without vision. Supporting the hypothesis that IW exploits biomechanical consequences of the act of gesturing, we find that: (1) gestures with larger physical impulses co-occur with greater head movement, (2) gesture-speech synchrony relates to larger gesture-concurrent head movements (i.e. for bimanual gestures), (3) when vision is blocked, gestures generate more physical impulse, and (4) moments of acoustic prominence couple more with peaks of physical impulse when vision is blocked. It can be concluded that IW’s gesturing ability is not based on a specialized language-based feedforward control as originally concluded from previous research, but is still dependent on a varied means of recurrent feedback from the body.

A psychophysical and neuroimaging analysis of genital hedonic sensation in men

Current understanding of human genital-brain interactions relates primarily to neuroendocrine and autonomic control, whereas interactions during sexual stimulation remain largely unexplored. Here we present a systematic approach towards identifying how the human brain encodes sensory genital information. Using a validated affective touch paradigm and functional magnetic resonance imaging, we found that hedonic responses to discriminatory versus affective tactile stimulation were distinctly different for both penile shaft and forearm. This suggests that, as with other body sites, genital skin contains small diameter mechanoreceptive nerve fibres that signal pleasant touch. In the brain, secondary somatosensory cortex (S2) distinguished between affective and discriminative touch for the penile shaft, but not for the forearm. Frenulum stimulation induced the greatest reports of subjective pleasure and led to the greatest deactivation of the default-mode network. This study represents a first pass at investigating, in humans, the relationship between innervation of genital surfaces, hedonic feelings, and brain mechanisms, in a systematic way.

Reliability and Validity of the Mongolian version of affective touch questionnaire

Communication via the sense of touch has long been perceived as an important aspect of human development, social comfort, and well-being. Human somatosensory system has in fact two tactile sub-modalities, one providing the well-recognized discriminative touch input to the brain, and the second–the affective or emotional input. C-tactile system is hypothesized to represent the neurobiological substrate for affective and rewarding properties of touch. Lower relationship quality is associated with lower resilience to stressors and can lead to increased vulnerability to mental health disorders. Based on the existing work, we know that social touch can increase well-being and lower state-anxiety. Our goal was to prove content validity for the Mongolian version with the factor structure of the original English version of the TEAQ. We translated, and adapted TEAQ for Mongolian language version. Original TEAQ-117 items were used in the pilot study. In the present study, enrolled 204 participants, age varied between 18 and 57 years (26.9±8.8), 57.8% were female. Validated TEAQ-57 items English version was used, and Exploratory factor analysis confirmed 55 items with 6 component structure. Confirmatory factor analysis demonstrated good consistency and homogeneity of the 6 factor structure of the TEAQ, and satisfactory model fit. Several subscales of the TEAQ revealed positive correlations on quality of life domains, in contrast negative correlations with anxiety and depression. In conclusion, analysed Mongolian version of the TEAQ-55 is a reliable and valid assessment tool of experiences and attitudes towards touch, and similar to component structure for different cultures (Validated British TEAQ-57, and TEAQ-37 RUS). We expected that Mongolian version of the TEAQ might be a helpful tool for screening mental health issues and researchers.