Evaluation of psychosocial and biological parameters in women seeking for a caesarean section and women who are aiming for vaginal delivery: a cross-sectional study.

PURPOSE: To investigate psychosocial and biological parameters that may influence decision-making concerning the mode of delivery in women with caesarean section on maternal request (CSMR). METHODS: Two 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. RESULTS: Women 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). CONCLUSION: Women 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.

Changes in birth-related pain perception impact of neurobiological and psycho-social factors.

PURPOSE: To analyse post-partum short- and long-term pain sensitivity and the influence of endogenous pain inhibition as well as distinct psycho-social factors on birth-related pain. METHODS: Pain sensitivity was assessed in 91 primiparous women at three times: 2-6 weeks before, one to 3 days as well as ten to 14 weeks after childbirth. Application of a pressure algometer in combination with a cold pressor test was utilised for measurement of pain sensitivity and assessment of conditioned pain modulation (CPM). Selected psycho-social factors (anxiety, social support, history of abuse, chronic pain and fear of childbirth) were evaluated with standardised questionnaires and their effect on pain processing then analysed. RESULTS: Pressure pain threshold, cold pain threshold and cold pain tolerance increased significantly directly after birth (all p < 0.001). While cold pain parameters partly recovered on follow-up, pressure pain threshold remained increased above baseline (p < 0.001). These pain-modulating effects were not found for women with history of abuse. While CPM was not affected by birth, its extent correlated significantly (r = 0.367) with the drop in pain sensitivity following birth. Moreover, high trait anxiety predicted an attenuated reduction in pain sensitivity (r = 0.357), while there was no correlation with fear of childbirth, chronic pain and social support. CONCLUSION: Pain sensitivity showed a decrease when comparing post-partum with prepartum values. The extent and direction of CPM appear to be a trait variable that predicted post-partum hypalgesia without being changed itself. Post-partum hypalgesia was reduced in women with a history of abuse and high trait anxiety, which suggests that individual differences in CPM affect childbirth experience.

Incision and stress regulation in borderline personality disorder: neurobiological mechanisms of self-injurious behaviour.

BACKGROUND: Patients with borderline personality disorder frequently show non-suicidal self-injury (NSSI). In these patients, NSSI often serves to reduce high levels of stress. AIMS: Investigation of neurobiological mechanisms of NSSI in borderline personality disorder. METHOD: 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. RESULTS: 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. CONCLUSIONS: 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.

Simultaneous EEG/MEG yields complementary information of nociceptive evoked responses.

OBJECTIVE: Nociceptive stimuli have been studied either by dipolar modelling using electroencephalography (EEG) or magnetoencephalography (MEG), but rarely using both techniques simultaneously. This study aims to investigate the spatiotemporal representation of cortical activity in response to non-nociceptive (tactile) and nociceptive (laser) stimuli using parallel EEG-MEG recordings. METHODS: We performed simultaneous EEG and MEG recordings in 12 healthy subjects by applying pneumatic tactile and nociceptive laser stimuli on the right- and left-hand dorsum. We analyzed brain responses for both modalities and methods by means of global field power (GFP), and dipole source locations, strengths and orientations calculated in the depth to identify similarities and differences. RESULTS: Prominent GFP peaks were similar in EEG and MEG for tactile responses but different for nociceptive responses. CONCLUSIONS: Methodically, MEG was superior to EEG in detecting the earliest nociceptive laser-evoked components with earlier latency in primary- and secondary somatosensory cortices, whereas EEG was superior to MEG in detecting late nociceptive components due to radially oriented deeper cortical activity. SIGNIFICANCE: EEG and MEG revealed in part differential nociceptive waveform patterns, peak latencies, and source orientations, making combined recordings favorable to examine pain-related activity as a whole in high temporal-spatial resolution.

Cerebral processing of sharp mechanical pain measured with arterial spin labeling.

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.

Review of techniques useful for the assessment of sensory small fiber neuropathies: Report from an IFCN expert group.

Nerve conduction studies (NCS) are an essential aspect of the assessment of patients with peripheral neuropathies. However, conventional NCS do not reflect activation of small afferent fibers, including Aδ and C fibers. A definitive gold standard for laboratory evaluation of these fibers is still needed and therefore, clinical evaluation remains fundamental in patients with small fiber neuropathies (SFN). Several clinical and research techniques have been developed for the assessment of small fiber function, such as (i) microneurography, (ii) laser evoked potentials, (iii) contact heat evoked potentials, (iv) pain-related electrically evoked potentials, (v) quantitative thermal sensory testing, (vi) skin biopsy-intraepidermal nerve fiber density and (vii) corneal confocal microscopy. The first five are physiological techniques, while the last two are morphological. They all have advantages and limitations, but the combined use of an appropriate selection of each of them would lead to gathering invaluable information for the diagnosis of SFN. In this review, we present an update on techniques available for the study of small afferent fibers and their clinical applicability. A summary of the anatomy and important physiological aspects of these pathways, and the clinical manifestations of their dysfunction is also included, in order to have a minimal common background.

Dipole source analyses of laser evoked potentials obtained from subdural grid recordings from primary somatic sensory cortex.

The cortical potentials evoked by cutaneous application of a laser stimulus (laser evoked potentials, LEP) often include potentials in the primary somatic sensory cortex (S1), which may be located within the subdivisions of S1 including Brodmann areas 3A, 3B, 1, and 2. The precise location of the LEP generator may clarify the pattern of activation of human S1 by painful stimuli. We now test the hypothesis that the generators of the LEP are located in human Brodmann area 1 or 3A within S1. Local field potential (LFP) source analysis of the LEP was obtained from subdural grids over sensorimotor cortex in two patients undergoing epilepsy surgery. The relationship of LEP dipoles was compared with dipoles for somatic sensory potentials evoked by median nerve stimulation (SEP) and recorded in area 3B (see Baumgärtner U, Vogel H, Ohara S, Treede RD, Lenz FA. J Neurophysiol 104: 3029-3041, 2010). Both patients had an early radial dipole in S1. The LEP dipole was located medial, anterior, and deep to the SEP dipole, which suggests a nociceptive dipole in area 3A. One patient had a later tangential dipole with positivity posterior, which is opposite to the orientation of the SEP dipole in area 3B. The reversal of orientations between modalities is consistent with the cortical surface negative orientation resulting from superficial termination of thalamocortical neurons that receive inputs from the spinothalamic tract. Therefore, the present results suggest that the LEP may result in a radial dipole consistent with a generator in area 3A and a putative later tangential generator in area 3B.

Comparison of LEP and QST and their contribution to standard sensory diagnostic assessment of spinal lesions: a pilot study.

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.

Posterior insular activity contributes to the late laser-evoked potential component in EEG recordings.

OBJECTIVE: Nociceptive activity in some brain areas has concordantly been reported in EEG source models, such as the anterior/mid-cingulate cortex and the parasylvian area. Whereas the posterior insula has been constantly reported to be active in intracortical and fMRI studies, non-invasive EEG and MEG recordings mostly failed to detect activity in this region. This study aimed to determine an appropriate inverse modeling approach in EEG recordings to model posterior insular activity, assuming the late LEP (laser evoked potential) time window to yield a better separation from other ongoing cortical activity. METHODS: In 12 healthy volunteers, nociceptive stimuli of three intensities were applied. LEP were recorded using 32-channel EEG recordings. Source analysis was performed in specific time windows defined in the grand-average dataset. Two distinct dipole-pairs located close to the operculo-insular area were compared. RESULTS: Our results show that posterior insular activity yields a substantial contribution to the latest part (positive component) of the LEP. CONCLUSIONS: Even though the initial insular activity onset is in the early LEP time window,modelingthe insular activity in the late LEP time window might result in better separation from other ongoing cortical activity. SIGNIFICANCE: Modeling the late LEP activity might enable to distinguish posterior insular activity.

Modality-specific facilitation of noninjurious sharp mechanical pain by topical capsaicin.

We had previously shown that a "blunt blade" stimulator can mimic the noninjurious strain phase of incisional pain, but not its sustained duration. Here, we tested whether acute sensitization of the skin with topical capsaicin can add the sustained phase to this noninvasive surrogate model of intraoperative pain. Altogether, 110 healthy volunteers (55 male and 55 female; 26 ± 5 years) participated in several experiments using the "blunt blade" (0.25 × 4 mm) on normal skin (n = 36) and on skin pretreated by a high-concentration capsaicin patch (8%, Qutenza; n = 36). These data were compared with an experimental incision (n = 40) using quantitative and qualitative pain ratings by numerical rating scale and SES Pain Perception Scale descriptors. Capsaicin sensitization increased blade-induced pain magnitude and duration significantly (both P < 0.05), but it failed to fully match the sustained duration of incisional pain. In normal skin, the SES pattern of pain qualities elicited by the blade matched incision in pain magnitude and pattern of pain descriptors. In capsaicin-treated skin, the blade acquired a significant facilitation only of the perceived heat pain component (P < 0.001), but not of mechanical pain components. Thus, capsaicin morphed the descriptor pattern of the blade to become more capsaicin-like, which is probably explained best by peripheral sensitization of the TRPV1 receptor. Quantitative sensory testing in capsaicin-sensitized skin revealed hyperalgesia to heat and pressure stimuli, and loss of cold and cold pain sensitivity. These findings support our hypothesis that the blade models the early tissue-strain-related mechanical pain phase of surgical incisions.

Multiple somatotopic representations of heat and mechanical pain in the operculo-insular cortex: a high-resolution fMRI study.

Whereas studies of somatotopic representation of touch have been useful to distinguish multiple somatosensory areas within primary (SI) and secondary (SII) somatosensory cortex regions, no such analysis exists for the representation of pain across nociceptive modalities. Here we investigated somatotopy in the operculo-insular cortex with noxious heat and pinprick stimuli in 11 healthy subjects using high-resolution (2 × 2 × 4 mm) 3T functional magnetic resonance imaging (fMRI). Heat stimuli (delivered using a laser) and pinprick stimuli (delivered using a punctate probe) were directed to the dorsum of the right hand and foot in a balanced design. Locations of the peak fMRI responses were compared between stimulation sites (hand vs. foot) and modalities (heat vs. pinprick) within four bilateral regions of interest: anterior and posterior insula and frontal and parietal operculum. Importantly, all analyses were performed on individual, non-normalized fMRI images. For heat stimuli, we found hand-foot somatotopy in the contralateral anterior and posterior insula [hand, 9 ± 10 (SD) mm anterior to foot, P < 0.05] and in the contralateral parietal operculum (SII; hand, 7 ± 10 mm lateral to foot, P < 0.05). For pinprick stimuli, we also found somatotopy in the contralateral posterior insula (hand, 9 ± 10 mm anterior to foot, P < 0.05). Furthermore, the response to heat stimulation of the hand was 11 ± 12 mm anterior to the response to pinprick stimulation of the hand in the contralateral (left) anterior insula (P < 0.05). These results indicate the existence of multiple somatotopic representations for pain within the operculo-insular region in humans, possibly reflecting its importance as a sensory-integration site that directs emotional responses and behavior appropriately depending on the body site being injured.

Dipole source analyses of early median nerve SEP components obtained from subdural grid recordings.

The median nerve N20 and P22 SEP components constitute the initial response of the primary somatosensory cortex to somatosensory stimulation of the upper extremity. Knowledge of the underlying generators is important both for basic understanding of the initial sequence of cortical activation and to identify landmarks for eloquent areas to spare in resection planning of cortex in epilepsy surgery. We now set out to localize the N20 and P22 using subdural grid recording with special emphasis on the question of the origin of P22: Brodmann area 4 versus area 1. Electroencephalographic dipole source analysis of the N20 and P22 responses obtained from subdural grids over the primary somatosensory cortex after median nerve stimulation was performed in four patients undergoing epilepsy surgery. Based on anatomical landmarks, equivalent current dipoles of N20 and P22 were localized posterior to (n = 2) or on the central sulcus (n = 2). In three patients, the P22 dipole was located posterior to the N20 dipole, whereas in one patient, the P22 dipole was located on the same coordinate in anterior-posterior direction. On average, P22 sources were found to be 6.6 mm posterior [and 1 mm more superficial] compared with the N20 sources. These data strongly suggest a postcentral origin of the P22 SEP component in Brodmann area 1 and render a major precentral contribution to the earliest stages of processing from the primary motor cortex less likely.

The glutamate to γ-aminobutyric acid ratio in the posterior insula is associated with pain perception in healthy women but not in women with borderline personality disorder.

This study aimed to investigate whether the differences in pain perception between patients with borderline personality disorder (BPD) and healthy subjects (HCs) can be explained by differences in the glutamate/GABA ratio in the posterior insula. In total, 29 BPD patients and 31 HCs were included in the statistical analysis. Mechanical pain sensitivity was experimentally assessed with pinprick stimuli between 32 and 512 mN on a numeric rating scale. The metabolites were measured in the right posterior insula using the MEshcher-GArwood Point-RESolved Spectroscopy sequence for single-voxel magnetic resonance spectroscopy (1H-MRS). The 256- and the 512-mN pinprick stimuli were perceived as significantly less painful by the BPD patient group compared with HCs. No differences were found between groups for the glutamate/GABA ratios. A positive correlation between the glutamate/GABA ratio and the pain intensity ratings to 256- and 512-mN pinpricks could be found in the combined and in the HC group. In the BPD patient group, the correlations between the glutamate/GABA ratio and the pain intensity ratings to 256- and 512-mN pinpricks did not reach significance. In conclusion, the study showed that individual differences in pain perception may in part be explained by the individual glutamate/GABA ratio in the posterior insula. However, this possible mechanism does not explain the differences in pain perception between BPD patients and HCs.

Differential perception of sharp pain in patients with borderline personality disorder.

BACKGROUND: Cutting is the most common method of non-suicidal self-injury (NSSI) to reduce inner tension in patients with Borderline Personality Disorder (BPD). Aim of this study was to compare pain perception induced by an incision and by application of a surrogate model for sharp mechanical pain (a non-invasive "blade") in BPD. METHODS: 22 female patients and 20 healthy controls (HC) received a small incision into the volar forearm, a 7s-blade application on the same side, and non-invasive phasic stimuli (pinprick, blade, laser, tactile). Pain intensity as well as affective versus sensory components were assessed. RESULTS: Incision was rated similarly by both groups (BPD: 28.6 ± 5.5 vs. HC: 33.9 ± 6.6; mean maximum pain ± SEM; p > 0.8), without significant difference for "7-s-blade" (BPD: 18.1 ± 3.8 vs. HC: 25.3 ± 3.6; mean maximum pain ± SEM; p > 0.17) or between "7-s-blade" and incision (BPD: p > 0.12; HC: p > 0.84). However, patients' intensity ratings returned significantly faster to baseline after incision (BPD: 38.9 ± 12.6 s vs. HC: 74.52 ± 11.5 s; p < 0.05), and patients evaluated "blade" and incision without any affective and with different sensory descriptors, indicating an altered evaluation of NSSI-like stimulation with qualitative in addition to quantitative differences-especially for the sharp pain component. CONCLUSIONS: The reduced perception of suprathreshold nociceptive stimuli is based on a missing affective component and specific loss of the perception of "sharpness" as part of the sensory component of pain. The results further demonstrate the usefulness of the "blade" for the perception of sharpness in patients. SIGNIFICANCE: Patients with Borderline Personality Disorder (BPD) who engage in non-suicidal self-injury (NSSI) report less pain in response to phasic nociceptive stimuli. In comparing an invasive pain stimulus to phasic nociceptive stimuli in BPD patients, the "blade" as non-invasive surrogate model for sharp mechanical pain in psychiatric patients is used. In contrast to healthy volunteers, BPD patients do not report significant affective ratings and specifically display a reduced sensory component for sharpness.

Effects of a Painful Stimulus on Stress Regulation in Male Patients With Borderline Personality Disorder: A Pilot Study.

Pain processing in relation to stress has so far not been investigated in male patients with borderline personality disorder (BPD). This experimental pilot study examined 17 male BPD patients and 20 male healthy controls (HCs) to assess the effects of a pain stimulus on arousal, aggression, pain (ratings), and heart rate. At baseline, BPD patients showed significantly higher arousal and aggression; however, there was no significant difference in heart rate compared to the HC group. Following stress induction, a noninvasive mechanical pain stimulus was applied. No significant differences in pain ratings or heart rates were found between the groups. For arousal, a significantly stronger decrease was revealed in the BPD group compared to the HC group (t = 2.16, p = .038). Concerning aggression, the BPD group showed a significantly greater decrease after the pain stimulus than the HC group (t = 3.25, p = .002). This data showed that nonsuicidal self-injury can reduce arousal and aggression in male BPD.

Hemispheric asymmetry of hand representation in human primary somatosensory cortex and handedness.

OBJECTIVE: To evaluate interhemispheric differences of hand representation in primary somatosensory (SI) and motor (MI) cortices and its relation to handedness. METHODS: MRI-based EEG dipole source analysis was performed separately for early (P14, N20, P22) and middle/late latency (P30, N60, N110) SEP components after left and right median nerve stimulation. In addition, the location of the MI hand area (Omega region) and handedness were determined. RESULTS: Equivalent current dipoles (ECDs) of N20, P30 and N60 SEP components were localized in contralateral SI (area 3b, N20 and P30; area 1, N60), the mean P22 ECD localization was in area 4 of contralateral MI. In contrast to the Omega region and the precentral P22 component, ECDs in both areas 3b and 1 were located more laterally in the right than in the left hemisphere. ECDs in the right SI lay more laterally than the ipsilateral Omega region. Asymmetry in SI was not correlated with handedness. CONCLUSIONS: The data demonstrate that the location of hand representation shows relevant hemispheric asymmetry in human SI, both in areas 3b and 1. SIGNIFICANCE: Hemispheric asymmetry in SI must be considered in the studies on cortical reorganization and plasticity in SI as well as for transcranial magnetic stimulation (TMS) over SI.

Posterior Insular GABA Levels Inversely Correlate with the Intensity of Experimental Mechanical Pain in Healthy Subjects.

This study aimed to investigate the relation of GABA and glutamate levels in the posterior insula and mechanical pain sensitivity in healthy subjects. Nineteen healthy female individuals underwent single voxel magnetic resonance spectroscopy (MRS) at 3 T. Metabolites were measured in the right posterior insula using MEGA-PRESS spectral editing. Mechanical pain sensitivity was experimentally assessed with pinprick stimuli on a numeric rating scale. Ratings of perceived intensity of 256 mN and 512 mN pinprick stimuli were negatively correlated with GABA levels and positively with glutamate levels in the posterior insula. Pinprick pain ratings were also positively correlated with the glutamate/GABA ratio. No significant correlation for pinprick stimuli of lower forces than 256 mN was observed. The results of our study support the hypothesis that excitatory and inhibitory neurotransmitter levels and/or the ratio of glutamate/GABA levels in the posterior insula are related to individual differences in pain sensitivity. These results are in line with chronic pain studies, where elevated glutamate/GABA ratios in the insular cortex of patients with chronic pain syndromes were observed.

Stress reactivity and pain-mediated stress regulation in remitted patients with borderline personality disorder.

Objective: Patients with borderline personality disorder (BPD) use nonsuicidal self-injury (NSSI) to cope with states of elevated inner tension. It is unclear to what extent remitted BPD patients experience these states and whether the experience of pain still regulates emotion. The purpose of this study was the investigation of baseline stress levels, stress reactivity, and pain-mediated stress regulation in remitted BPD patients. Method: Subjective and objective stress parameters were assessed in 30 remitted BPD patients, 30 current BPD patients, and 30 healthy controls. After stress induction, a non-nociceptive tactile stimulus, a tissue-injuring, or a noninvasive pain stimulus was applied to the right volar forearm. Results: Baseline stress levels of remitted BPD patients lie in between the stress levels of current BPD patients and healthy controls. Urge for NSSI increased significantly more in current than remitted BPD patients. The experience of pain led to a greater decrease of arousal in current compared to remitted BPD patients and healthy controls. Conclusions: States of increased tension still seem to appear in remitted BPD patients. The role of pain-mediated stress regulation appears to be reduced in remitted patients.

The role of nociceptive input and tissue injury on stress regulation in borderline personality disorder.

Approximately 60% to 90% of patients with borderline personality disorder (BPD) show nonsuicidal self-injurious behavior (NSSI) with cutting being the most frequently applied method. One of NSSI's functions is to reduce aversive tension. Previous studies have found a tension-reducing effect of painful tissue injury by an incision. It is still unclear whether this effect is based on the effect of tissue injury or the effect of pain experience, or both. The aim of this study was to determine whether tissue injury leads to a stronger stress reduction than a sole pain stimulus in patients with BPD. After stress induction, 57 BPD patients and 60 healthy controls (HCs) received either an incision or a non-tissue-injuring mechanical nociceptive stimulus ("blade") typically perceived as painful or a non-nociceptive tactile sham stimulus (blunt end of scalpel). Participants were unaware of which procedure was applied. For stress assessment, subjective and objective parameters were measured. As immediate response to the stimulus application, we found greater stress reduction after both painful stimuli (incision and blade) in BPD patients but no difference in stress decrease between the tissue-injuring incision and the non-tissue-injuring pain stimulus (blade). Compared with HCs, incision and blade were followed by greater immediate decrease of arousal in BPD patients. Our findings confirm that among BPD patients, the nociceptive input leads to stress reduction. In contrast, the impact of tissue damage on stress reduction was relatively small. In addition, the results suggest that painful stimuli lead to a greater stress reduction in BPD patients compared with HCs.

Evidence for early activation of primary motor cortex and SMA after electrical lower limb stimulation using EEG source reconstruction.

Compared to median nerve somatosensory evoked potentials (SEP), less is known about activity evoked by nerve stimulation of the lower limb. To understand the mechanisms and the physiology of sensor- and motor control it is useful to investigate the sensorimotor functions as revealed by a standardized functional status. Therefore, we investigated SEPs of the lower limb in 6 healthy male volunteers. For each side, tibial and peroneal nerves were stimulated transcutaneously at the fossa poplitea. The tibial nerves were also stimulated further distally at the ankle joint. Source localization was applied to 64-EEG-channel data of the SEPs. In contrast to somatosensory areas, which are activated after median nerve stimulation, we found dipoles adjacent to motor areas near Brodmann area 4 (BA 4) for SEP components P 32/40 and P 54/60 and near the supplementary motor area (SMA) for the N 75/83 component. These sources could reliably be distinguished for each individual subject as well as for the grand mean data set. Our data show that afferent projections from the lower limb mainly reach primary motor areas (BA 4) and only subsequently, with a delay of 40 ms, higher order motor areas such as SMA. We conclude that a focused view on SEP of the lower limb could be a useful tool to investigate pathological states in motor control or peripheral deafferentiation.