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Patients with borderline personality disorder frequently show non-suicidal self-injury (NSSI). In these patients, NSSI often serves to reduce high levels of stress. Investigation of neurobiological mechanisms of NSSI in borderline personality disorder. In total, 21 women with borderline personality disorder and 17 healthy controls underwent a stress induction, followed by either an incision into the forearm or a sham treatment. Afterwards participants underwent resting-state functional magnetic resonance imaging while aversive tension, heart rate and heart rate variability were assessed. We found a significant influence of incision on subjective and objective stress levels with a stronger decrease of aversive tension in the borderline personality disorder group following incision than sham. Amygdala activity decreased more and functional connectivity with superior frontal gyrus normalised after incision in the borderline personality disorder group. Decreased stress levels and amygdala activity after incision support the assumption of an influence of NSSI on emotion regulation in individuals with borderline personality disorder and aids in understanding why these patients use self-inflicted pain to reduce inner tension.

A(δ) and C fibers are the major pain-conducting nerve fibers, activate only partly the same brain areas, and are differently involved in pain syndromes. Whether a stimulus excites predominantly A(δ) or C fibers is a commonly asked question in basic pain research but a quick test was lacking so far. Of 77 verbal descriptors of pain sensations, \"pricking\", \"dull\" and \"pressing\" distinguished best (95% cases correctly) between A(δ) fiber mediated (punctate pressure produced by means of von Frey hairs) and C fiber mediated (blunt pressure) pain, applied to healthy volunteers in experiment 1. The sensation was assigned to A(δ) fibers when \"pricking\" but neither \"dull\" nor \"pressing\" were chosen, and to C fibers when the sum of the selections of \"dull\" or \"pressing\" was greater than that of the selection of \"pricking\". In experiment 2, with an independent cohort, the three-descriptor questionnaire achieved sensitivity and specificity above 0.95 for distinguishing fiber preferential non-mechanical induced pain (laser heat, exciting A(δ) fibers, and 5-Hz electric stimulation, exciting C fibers). A three-item verbal rating test using the words \"pricking\", \"dull\", and \"pressing\" may provide sufficient information to characterize a pain sensation evoked by a physical stimulus as transmitted via A(δ) or via C fibers. It meets the criteria of a screening test by being easy to administer, taking little time, being comfortable in handling, and inexpensive while providing high specificity for relevant information.

Background Aδ and C fibers are the major pain-conducting nerve fibers, activate only partly the same brain areas, and are differently involved in pain syndromes. Whether a stimulus excites predominantly Aδ or C fibers is a commonly asked question in basic pain research but a quick test was lacking so far. Methodology/Principal Findings Of 77 verbal descriptors of pain sensations, “pricking”, “dull” and “pressing” distinguished best (95% cases correctly) between Aδ fiber mediated (punctate pressure produced by means of von Frey hairs) and C fiber mediated (blunt pressure) pain, applied to healthy volunteers in experiment 1. The sensation was assigned to Aδ fibers when “pricking” but neither “dull” nor “pressing” were chosen, and to C fibers when the sum of the selections of “dull” or “pressing” was greater than that of the selection of “pricking”. In experiment 2, with an independent cohort, the three-descriptor questionnaire achieved sensitivity and specificity above 0.95 for distinguishing fiber preferential non-mechanical induced pain (laser heat, exciting Aδ fibers, and 5-Hz electric stimulation, exciting C fibers). Conclusion A three-item verbal rating test using the words “pricking”, “dull”, and “pressing” may provide sufficient information to characterize a pain sensation evoked by a physical stimulus as transmitted via Aδ or via C fibers. It meets the criteria of a screening test by being easy to administer, taking little time, being comfortable in handling, and inexpensive while providing high specificity for relevant information.

Introduction Arterial spin labeling (ASL) is a functional neuroimaging technique that has been frequently used to investigate acute pain states. A major advantage of ASL as opposed to blood‐oxygen‐level‐dependent functional neuroimaging is its applicability for low‐frequency designs. As such, ASL represents an interesting option for studies in which repeating an experimental event would reduce its ecological validity. Whereas most ASL pain studies so far have used thermal stimuli, to our knowledge, no ASL study so far has investigated pain responses to sharp mechanical pain. Methods As a proof of concept, we investigated whether ASL has the sensitivity to detect brain activation within core areas of the nociceptive network in healthy controls following a single stimulation block based on 96 s of mechanical painful stimulation using a blunt blade. Results We found significant increases in perfusion across many regions of the nociceptive network such as primary and secondary somatosensory cortices, premotor cortex, posterior insula, inferior parietal cortex, parietal operculum, temporal gyrus, temporo‐occipital lobe, putamen, and the cerebellum. Contrary to our hypothesis, we did not find any significant increase within ACC, thalamus, or PFC. Moreover, we were able to detect a significant positive correlation between pain intensity ratings and pain‐induced perfusion increase in the posterior insula. Conclusion We demonstrate that ASL is suited to investigate acute pain in a single event paradigm, although to detect activation within some regions of the nociceptive network, the sensitivity of our paradigm seemed to be limited. Regarding the posterior insula, our paradigm was sensitive enough to detect a correlation between pain intensity ratings and pain‐induced perfusion increase. Previous experimental pain studies have proposed that intensity coding in this region may be restricted to thermal stimulation. Our result demonstrates that the posterior insula encodes intensity information for mechanical stimuli as well. Using arterial spin labeling (ASL), one single block of sharp mechanical pain stimulation (96 s) induced perfusion increase in many areas of the nociceptive network. Moreover, a positive correlation between pain intensity ratings and perfusion increase in the posterior insula could be detected. Our results demonstrate that ASL constitutes a powerful alternative to BOLD fMRI for low‐frequency designs and that pain intensity coding in the posterior insula is not restricted to thermal stimulation.

To determine how opiate receptor distribution is co-localized with the distribution of nociceptive areas in the human brain, eleven male healthy volunteers underwent one PET scan with the subtype-nonselective opioidergic radioligand [ 18F]fluoroethyl-diprenorphine under resting conditions. The binding potential (BP), a parameter for the regional cerebral opioid receptor availability, was computed using the occipital cortex as reference region. The following regions of interest (ROIs) were defined on individual MR images: thalamus, sensory motor strip (SI/MI area), frontal operculum, parietal operculum, anterior insular cortex, posterior insular cortex, anterior cingulate cortex (ACC; peri- and subgenual part of “classical ACC” only), midcingulate cortex (MCC, posterior part of “classical ACC”), putamen, caudate nucleus and the amygdala. BP for [ 18F]fluoroethyl-diprenorphine was lowest in the sensory motor strip (0.30). Highest BP was found in thalamus (1.36), basal ganglia (putamen 1.22, caudate 1.16) and amygdala (1.21). In the cingulate cortex, ACC (1.11) had higher BP than MCC (0.86). In the operculo-insular region, we found high BPs in all ROIs: anterior insula (1.16), posterior insula (1.05), frontal operculum (0.99) and parietal operculum (0.77). Factor analysis of interindividual variability of opiate receptor BP revealed four factors (95% explained variance): (1) operculo-insular areas, ACC, MCC and putamen, (2) amygdala and thalamus, (3) caudate and thalamus, (4) SI/MI and MCC. Nociceptive areas of the lateral pain system (frontoparietal operculum and insula) have opiate receptor BPs significantly higher than SI/MI, comparable to anterior and midcingulate areas of the medial pain system. These findings suggest that the cortical anti-nociceptive effects of opiates are not only mediated by ACC and MCC, but also by the operculo-insular cortex, if it can be assumed that opioid binding mediates anti-nociception in those structures.

Pain perception comprises sensory and emotional dimensions. While the emotional experience is thought to be represented in the right hemisphere, we here report a left-hemisphere dominance for the early sensory component of pain perception using brain electrical source analysis of laser-evoked potentials. Ten right-handed subjects underwent several series of laser radiant heat stimuli to pairs of parallel lines on the dorsum of the left or right hand. Stimulus location and intensity were randomised independently. The sensory-discriminative aspects of pain were emphasised by asking the subjects to perform either a spatial or an intensity discrimination task and were contrasted with active distraction by mental arithmetics. Pain ratings obtained after each of the laser stimulus series revealed an analgesic effect of distraction (27%, P < 0.001). Four equivalent dipole sources were active in the latency range of 100–200 ms (bilateral operculoinsular cortex, midcingulate gyrus, postcentral gyrus). The sources in the operculoinsular cortex exhibited (a) the shortest peak latency (155 ± 6 ms), (b) the most pronounced enhancement during spatial and intensity discrimination tasks compared to active distraction (43%, P < 0.001), and (c) a significantly stronger source activity in the left hemisphere independent of stimulation side (23%, P < 0.05). The distribution of these sources extended into the dorsal insula. The postcentral source had the longest peak latency (180 ± 7 ms); its source strength was task-dependent (25%, P = 0.051) but exhibited no hemisphere dominance. The midcingulate source had an intermediate peak latency (169 ± 7 ms). Its source strength was modulated by tasks, but this modulation was significant only in the latency range >200 ms (46%, P < 0.001). These findings suggest a dominant role of the left frontal operculum and adjacent dorsal insula in the early sensory-discriminative dimensions of pain processing. This region has been proposed to be the cortical projection target of nociceptive pathways from the spinal cord to the ventroposteroinferior and ventromedial (its posterior part: VMpo) thalamic nuclei.

Being able to remember physically and emotionally painful events in one's own past may shape behavior, and can create an aversion to a variety of situations. Pain imagination is a related process that may include recall of past experiences, in addition to production of sensory and emotional percepts without external stimuli. This study aimed to understand 1) the central nervous system processes that underlie pain imagination, 2) the retrieval of pain memories, and 3) to compare the latter with visual object memory. These goals were achieved by longitudinally investigating brain function with functional magnetic resonance imaging in a unique group of healthy volunteers who had never experienced tooth pain. In these subjects, we compared brain responses elicited during three experimental conditions in the following order: imagination of tooth pain (pain imagination), remembering one's own house (object memory), and remembrance of tooth pain following an episode of induced acute tooth pain (pain memory). Key observations stemming from group-level conjunction analyses revealed common activation in the posterior parietal cortex for both pain imagination and pain memory, while object and pain memory each had strong activation predominantly within the middle frontal gyrus. When contrasting pain imagination and memory, significant activation differences were observed in subcortical structures (ie, parahippocampus - pain imagination > pain memory; midbrain - pain memory > pain imagination). Importantly, these findings were observed in the presence of consistent and reproducible psychophysical and behavioral measures that informed on the subjects' ability to imagine novel and familiar thoughts, as well as the subjects' pain perception.

This study evaluates the additional use of laser-evoked potentials (LEP) and quantitative sensory testing (QST) in the sensory assessment of spinal lesions. Four consecutive patients with spinal lesions verified by MRI and clinical evidence for mild spinothalamic tract involvement were included. The electrophysiological workup [somatosensory evoked potentials (SEP) and LEP] was compared to QST. Electrophysiology and QST were reassessed after about 6 months. LEP detected impaired spinothalamic tract function in 7/8 examinations. QST pointed to spinothalamic tract lesions by loss of thermal function (3/8); most frequent positive sensory signs (3/8) were paradoxical heat sensations. LEP and QST results were concordant in 6/8 examinations. SEPs were abnormal in 2/8 examinations. Congruent results between SEP and both LEP and QST were obtained in 3/8 examinations. LEP detected more deficits than any single QST parameter or their combination but additional QST allows the detection of positive sensory signs. The diagnostic gain of SEP was limited.

Brain asymmetry is a phenomenon well known for handedness and language specialization and has also been studied in motor cortex. Less is known about hemispheric asymmetries in the somatosensory cortex. In the present study, we systematically investigated the representation of somatosensory function analyzing early subcortical and cortical somatosensory-evoked potentials (SEP) after electrical stimulation of the right and left median nerve. In 16 subjects, we compared thresholds, the peripheral neurogram at Erb point, and, using MRI-based EEG source analysis, the P14 brainstem component as well as N20 and P22, the earliest cortical responses from the primary sensorimotor cortex. Handedness was documented using the Edinburgh Inventory and a dichotic listening test was performed as a measure for language dominance. Whereas thresholds, Erb potential, and P14 were symmetrical, amplitudes of the cortical N20 showed significant hemispheric asymmetry. In the left hemisphere, the N20 amplitude was higher, its generator was located further medial, and it had a stronger dipole moment. There was no difference in dipole orientation. As a possible morphological correlate, the size of the left postcentral gyrus exceeded that of the right. The cortical P22 component showed a lower amplitude and a trend toward weaker dipole strength in the left hemisphere. Across subjects, there were no significant correlations between laterality indices of N20, the size of the postcentral gyrus, handedness, or ear advantage. These data show that asymmetry of median nerve SEP occurs at the cortical level, only. However, both functional and morphological cortical asymmetry of somatosensory representation appears to vary independently of motor and language functions.

PurposeTo investigate psychosocial and biological parameters that may influence decision-making concerning the mode of delivery in women with caesarean section on maternal request (CSMR).MethodsTwo hundred and two women were enrolled prospectively. The study sample (n = 93) consisted of women who aimed for CSMR, the control sample were women who seeked for vaginal delivery (n = 109). Parturients of both samples were enrolled during the pre-birth counselling at the delivery room at the University Medical Centre Mannheim, University Heidelberg, Germany. Women completed standardised questionnaires regarding psychosocial burden (SCL-R 90), fear of childbirth (W-DEQ) and anxiety (STAI), personality structure (HEXACO-Pi-R), and ambiguity tolerance (PFI, PNS, and NFC), social support (F-SozU) as well as one questionnaire assessing demographic parameters and further factors potentially influencing their choice of the mode of delivery. Hair cortisol concentration as a marker for chronic psychological stress and pressure pain threshold with a pressure algometer was assessed.ResultsWomen in the CSMR sample had less social support (F-SozU: 2.99 ± 0.52 vs. 3.12 ± 0.32; p = 0.043) and were less educated (high school or university degree: 37 vs. 71%, p = 0.001) compared to parturients of the control sample. Women who underwent CSMR were less open-minded (HEXACO-Pi-R: 3.08 ± 0.57 vs. 3.26 ± 0.50; p = 0.016) and less extroverted (HEXACO-Pi-R: 3.34 ± 0.36 vs. 3.46 ± 0.41; p = 0.041). The control collective showed higher scores in negative appraisal of the birth (‘W-DEQ-negative appraisal’: 2.5 ± 0.8 vs. 2.2 ± 0.9; p = 0.006), whereas “lack of positive anticipation” was higher in the study collective (‘W-DEQ-lack of positive anticipation’: 3.2 ± 1.2 vs. 2.8 ± 0.8; p = 0.015). The study collective had higher pressure pain threshold values (5.07 ± 2.06 vs. 4.35 ± 1.38; p = 0.007), while no significant differences were observed in hair cortisol concentration comparing both groups (5.0 ± 11.4 vs. 4.9 ± 8.3; p = 0.426). The majority of the control collective (80%) had chosen the vaginal route as their mode of delivery before pregnancy, whereas only 21% of the women in the study collective decided to undergo CSMR before conception. The advice of social sources including both medical and non-medical aspects was rated less important in the study sample, with significant differences indicating a lower relevance of counsel from friends (p = 0.002) and midwives (p < 0.001).ConclusionWomen who inquired a CSMR had lower social support, were less educated, more anxious, and had a lower sensitivity for physical pain compared to women seeking for spontaneous delivery. This should be considered when counselling women requiring CSMR and could be leverage points to intervene to reduce the continuously increasing CSMR rate.