The aim of the present study was to explore the specific pattern of brain deactivation elicited by painful stimuli, in contrast with that elicited by tactile stimuli. Functional magnetic resonance imaging (fMRI) data were collected from 62 healthy subjects under painful and tactile stimuli with varying intensities. The brain deactivations under different conditions were identified using the general linear model. Two-way analysis of variance (ANOVA) was performed to test whether there was a significant interaction between perceived stimulus intensity (factor 1: high intensity, low intensity) and stimulus modality (factor 2: pain, touch) on the brain deactivations. The results showed that there were significant interactions between stimulus intensity and stimulus modality on the deactivations of left medial superior frontal gyrus, left middle occipital gyrus, left superior frontal gyrus and right middle occipital gyrus (P < 0.05, Cluster-level FWE). The deactivations induced by painful stimuli with low perceived intensity (β = -3.38 ± 0.52) were significantly stronger than those induced by painful stimuli with high perceived intensity (β = -1.22 ± 0.54) (P < 0.001), whereas the differences between the deactivations induced by tactile stimuli with different perceived intensities were not statistically significant. In addition, there were no significant differences between the deactivations elicited by painful and tactile stimuli with the same stimulus intensities. These results suggest that there is a specific relationship between the deactivations induced by painful stimuli in multiple brain regions (such as the left medial superior frontal gyrus) and the stimulus intensity, providing evidence for a deeper understanding of the brain mechanisms underlying pain perception.
Humans ; Touch/physiology* ; Physical Stimulation/methods* ; Pain ; Brain/physiology* ; Magnetic Resonance Imaging/methods* ; Brain Mapping

Touch ; Signal Transduction ; Receptors, G-Protein-Coupled ; Touch Perception

Axilla/pathology* ; Breast Neoplasms/pathology* ; Female ; Humans ; Immunohistochemistry ; Intraoperative Period ; Lymph Nodes/pathology* ; Sensitivity and Specificity ; Sentinel Lymph Node/surgery* ; Sentinel Lymph Node Biopsy ; Touch

The reconstruction of tactile function during the repair of skin damage caused by factors including burns is inseparable from the functional regeneration of tactile receptor Merkel cells. Merkel cells mainly exist in the basal layer of the epidermis and are closely connected with nerves to form Merkel cell-nerve complexes, which play an important role in biological organisms. A large number of studies have shown that Merkel cells conduct precise transmission of mechanical force stimuli through the mechanically gated ion channels PIEZO2, and perform the function of tactile receptors. In this paper, we discussed the characteristics of Merkel cells and analyzed the different subgroups that may possibly exist in this type of cells and their functions, at the same time, we investigated the animal model research of touch-related diseases and the clinical diseases related to touch, revealing the importance of Merkel cell function research.
Animals ; Ion Channels/metabolism* ; Mechanotransduction, Cellular/physiology* ; Merkel Cells/physiology* ; Skin/metabolism* ; Touch/physiology*

Objective: To investigate the regularity of sensory recovery after repairing the wounds on the wrist and back of hand with anterolateral femoral flap without nerve anastomosis. Methods: A cross-sectional study was conducted. From January 2018 to December 2020, patients who underwent free anterolateral femoral flaps without nerve anastomosis to repair wounds on the wrist and back of hand and met the inclusion criteria in Changshu Hai Yu Health Centre and Suzhou Ruihua Orthopedic Hospital were included in this study. Depending on the time interval between the day of the patient's surgery and the day of the cross-sectional survey, 80 patients were divided into 6-month group (15 males and 5 females, aged 22-63 years), 12-month group (16 males and 4 females, aged 21-65 years), 18-month group (15 males and 5 females, aged 25-61 years), and 24-month group (14 males and 6 females, aged 20-65 years), with 20 patients in each group. The area of skin and soft tissue defects after debridement ranged from 6.0 cm×4.5 cm to 18.0 cm×9.0 cm. Anterolateral femoral flaps were cut with areas of 7 cm×5 cm to 20 cm×10 cm and a thickness of 1.0 to 2.5 cm. Each transplanted flap was divided into A (proximal), B/D (bilateral), C (distal), and E (central) regions. The pain sensation, touch sensation, cold sensation, warmth sensation, and two-point discrimination (2-PD) in the aforementioned five regions and the differences in the five senses of the whole flap were tested and compared. Data were statistically analyzed with one-way analysis of variance, Fisher's exact probability test, chi-square test, or McNemar test. Results: In A region of anterolateral femoral flap without nerve anastomosis, compared with those in 6-month group, the pain sensation, touch sensation, cold sensation, and warmth sensation of flap of patients in 12-month group were significantly recovered (with χ² values of 10.10, 14.55, 12.13, and 4.29, respectively, P<0.05 or P<0.01); compared with that in 12-month group, the warmth sensation of flap of patients in 18-month group recovered significantly (χ²=5.23, P<0.05). In B region, compared with those in 6-month group, the pain sensation, touch sensation, and cold sensation of flap of patients in 12-month group recovered significantly (with χ² values of 5.58, 3.96, and 4.29, respectively, P<0.05); compared with those in 12-month group, the pain sensation, touch sensation, cold sensation, and warmth sensation of flap of patients in 18-month group recovered significantly (with χ² values of 5.58, 3.96, 7.03, and 12.38, respectively, P<0.05 or P<0.01). In C region, compared with that in 6-month group, the pain sensation of flap of patients in 12-month group recovered significantly (χ²=4.80, P<0.05); Compared with that in 12-month group, the warmth sensation of flap of patients in 18-month group recovered significantly (χ²=10.16, P<0.01). In D region, compared with those in 6-month group, the pain sensation, touch sensation, and cold sensation of flap of patients in 12-month group recovered significantly (with χ² values of 5.58, 4.29, and 3.96, respectively, P<0.05); compared with those in 12-month group, the pain sensation, touch sensation, cold sensation, and warmth sensation of flap of patients in 18-month group recovered significantly (with χ² values of 5.58, 4.29, 3.96, and 10.10, respectively, P<0.05 or P<0.01). In E region, compared with that in 6-month group, the cold sensation of flap of patients in 12-month group recovered significantly (χ²=4.80, P<0.05); compared with those in 12-month group, the pain sensation, touch sensation, and warmth sensation of flap of patients in 18-month group recovered significantly (with χ² values of 6.47, 4.91, and 9.23, respectively, P<0.05 or P<0.01). The five senses in the 5 regions of flap of patients in 24-month group were similar to those in 18-month group (P>0.05). The recovery of 2-PD in the 5 regions of flap of patients was similar between the two adjacent groups (P>0.05). In 12-month group, the recoveries of pain sensation, touch sensation, and cold sensation of flap of patients in A region were better than those in the other 4 regions (P<0.05 or P<0.01), the recovery of warmth sensation was better than that of B region, C region, and E region (P<0.05 or P<0.01); in 18-month group, the recovery of pain sensation, touch sensation, cold sensation, and warmth sensation of flap of patients in A region of was better than those in area C region (P<0.05). Compared with those in 6-month group, the pain sensation, touch sensation, and cold sensation of the whole flap of patients in 12-month group recovered significantly (with χ² values of 7.62, 7.03, and 5.58, respectively, P<0.05 or P<0.01). Compared with the 12-month group in which 10, 11, 10, and 4 patients had a recovery of pain, touch sensation, cold sensation, and warmth sensation in the whole flap, the 18-month group had significantly more patients with sensations recovered, which were 17, 17, 16, and 14, respectively (with χ² values of 5.58, 4.29, 3.96, and 10.10, respectively, P<0.05 or P<0.01). The five senses of the whole flap of patients in 24-month group were similar to those in 18-month group (P>0.05). Conclusions: In the anterolateral femoral flap without nerve anastomosis for repairing wounds on the wrist and back of hand, the sensation gradually recovered from the proximal end to the distal end. The sensation of touch, pain, and cold began to recover from 6 months after operation, and entered the stable recover period at 18 months after operation. Warmth sensation began to recover from 12 months after operation, and entered the stable recovery period at 18 months after operation. The 2-PD of most flaps was still not recovered 2-year after operation.
Male ; Female ; Humans ; Wrist ; Cross-Sectional Studies ; Touch/physiology* ; Pain ; Anastomosis, Surgical

Humans ; Touch ; Touch Perception

Cartridge cases are crucial physical evidence in gun-related crimes. The successful identification of the touch DNA on cartridge cases can help to screen the suspects and reconstruct the gun-related crime scene. With the improvement of DNA extraction methods and the sensitivity of amplification kit, forensic examiners are expected to obtain more valuable information by testing the touch DNA on cartridge cases. In practical cases, the touch DNA detection on cartridge cases often encounters with low DNA content degradation, mixing and the gunshot residual interference, which brings more challenges to DNA examination and identification. This article reviews forensic research of touch DNA on the cartridge cases from the aspects of factors affecting touch DNA on cartridge cases, advances in the extraction and amplification methods, and the practical applications in order to provide reference for forensic identification of touch DNA on the cartridge cases in real cases.
Crime ; DNA/genetics* ; DNA Fingerprinting ; Forensic Genetics ; Touch

This paper discusses the short-term memory of vibro-tactile perception of human fingertips. By using a self-developed vibro-tactile expression device, a recall experiment was firstly carried out among 20 subjects aged 20-30 (10 males and 10 females) to discover the memory span about the vibro-tactile perception of human fingertips. Within this memory span, a cognitive experiment analyzing the recognition accuracy and the reaction time was carried out. The results showed: (1) The vibro-tactile memory span of human fingertip is 4 ± 1; (2) The vibro-tactile memory span increases as the discrete intensity between vibration stimuli increases; (3) Too long or too short vibration duration will reduce the vibro-tactile memory span, and the optimal vibration duration for men is 400 ms, for women is 300 ms; (4) The more the number of vibration stimuli is perceived by the human fingertip, the lower the recognition accuracy and the longer the reaction time it needs; (5) Compared with the vibration stimuli in disorder, people are more likely to remember the vibration stimuli in increasing/decreasing order; (6) The information extraction mechanism of the short-term memory about fingertip vibro-tactile perception bases a point to point scanning process among these stimuli. These results help to understand the human fingertip tactile characteristics and provide a physiological basis for the study of tactile feedback technologies.
Adult ; Female ; Fingers ; Humans ; Male ; Memory, Short-Term ; Touch ; Touch Perception ; Vibration ; Young Adult

Neuropathic pain is a chronic debilitating symptom characterized by spontaneous pain and mechanical allodynia. It occurs in distinct forms, including brush-evoked dynamic and filament-evoked punctate mechanical allodynia. Potassium channel 2.1 (Kir2.1), which exhibits strong inward rectification, is and regulates the activity of lamina I projection neurons. However, the relationship between Kir2.1 channels and mechanical allodynia is still unclear. In this study, we first found that pretreatment with ML133, a selective Kir2.1 inhibitor, by intrathecal administration, preferentially inhibited dynamic, but not punctate, allodynia in mice with spared nerve injury (SNI). Intrathecal injection of low doses of strychnine, a glycine receptor inhibitor, selectively induced dynamic, but not punctate allodynia, not only in naïve but also in ML133-pretreated mice. In contrast, bicuculline, a GABA receptor antagonist, induced only punctate, but not dynamic, allodynia. These results indicated the involvement of glycinergic transmission in the development of dynamic allodynia. We further found that SNI significantly suppressed the frequency, but not the amplitude, of the glycinergic spontaneous inhibitory postsynaptic currents (gly-sIPSCs) in neurons on the lamina II-III border of the spinal dorsal horn, and pretreatment with ML133 prevented the SNI-induced gly-sIPSC reduction. Furthermore, 5 days after SNI, ML133, either by intrathecal administration or acute bath perfusion, and strychnine sensitively reversed the SNI-induced dynamic, but not punctate, allodynia and the gly-sIPSC reduction in lamina IIi neurons, respectively. In conclusion, our results suggest that blockade of Kir2.1 channels in the spinal dorsal horn selectively inhibits dynamic, but not punctate, mechanical allodynia by enhancing glycinergic inhibitory transmission.
Animals ; Bicuculline ; pharmacology ; Disease Models, Animal ; Glycine ; metabolism ; Hyperalgesia ; drug therapy ; etiology ; metabolism ; Imidazoles ; pharmacology ; Inhibitory Postsynaptic Potentials ; drug effects ; physiology ; Male ; Mice, Inbred C57BL ; Neurons ; drug effects ; metabolism ; Neurotransmitter Agents ; pharmacology ; Peripheral Nerve Injuries ; drug therapy ; metabolism ; Phenanthrolines ; pharmacology ; Potassium Channels, Inwardly Rectifying ; antagonists & inhibitors ; metabolism ; Receptors, GABA-A ; metabolism ; Receptors, Glycine ; metabolism ; Strychnine ; pharmacology ; Synaptic Transmission ; drug effects ; physiology ; Tissue Culture Techniques ; Touch

Human functional MRI studies in acute and various chronic pain conditions have revolutionized how we view pain, and have led to a new theory that complex multi-dimensional pain experience (sensory-discriminative, affective/motivational, and cognitive) is represented by concurrent activity in widely-distributed brain regions (termed a network or pain matrix). Despite these breakthrough discoveries, the specific functions proposed for these regions remain elusive, because detailed electrophysiological characterizations of these regions in the primate brain are lacking. To fill in this knowledge gap, we have studied the cortical areas around the central and lateral sulci of the non-human primate brain with combined submillimeter resolution functional imaging (optical imaging and fMRI) and intracranial electrophysiological recording. In this mini-review, I summarize and present data showing that the cortical circuitry engaged in nociceptive processing is much more complex than previously recognized. Electrophysiological evidence supports the engagement of a distinct nociceptive-processing network within SI (i.e., areas 3a, 3b, 1 and 2), SII, and other areas along the lateral sulcus. Deafferentation caused by spinal cord injury profoundly alters the relationships between fMRI and electrophysiological signals. This finding has significant implications for using fMRI to study chronic pain conditions involving deafferentation in humans.
Animals ; Cerebral Cortex ; diagnostic imaging ; physiopathology ; Humans ; Pain ; diagnostic imaging ; pathology ; physiopathology ; Primates ; Touch ; physiology