Insular Cortical Thickness in Patients With Somatoform Pain Disorder: Are There Associations With Symptom Severity and Childhood Trauma?

Background: Studies show significant alterations in insular cortical thickness in patients with somatoform pain disorder (SPD). Additionally, associations between childhood maltreatment and morphometric alterations in insular cortex have been observed. Since patients with SPD often report about adverse childhood experiences, we were interested in the interrelationship of exposure to childhood maltreatment and insular cortical thickness in patients with SPD.

Neural mechanisms of perceptive and affective processing of body stimuli in anorexia nervosa - are there developmental effects?

Different components of body image processing seem to be reflected by different neural mechanisms. A core symptom of Anorexia nervosa (AN) is a disturbance of body image with correlates found on a neural level. The present study focuses on the neural processing of visual body stimuli of different weight categories in adolescent and adult AN patients.

Neural processing of food and emotional stimuli in adolescent and adult anorexia nervosa patients.

Background: A constant preoccupation with food and restrictive eating are main symptoms of anorexia nervosa (AN). Imaging studies revealed aberrant neural activation patterns in brain regions processing hedonic and reward reactions as well as-potentially aversive-emotions. An imbalance between so called "bottom-up" and "top-down" control areas is discussed.

The Brain Network of Itch Distraction.

is missing (Commentary).

Brain mechanisms of abnormal temperature perception in cold allodynia induced by ciguatoxin.

Objective: Cold allodynia occurs as a major symptom of neuropathic pain states. It remains poorly treated with current analgesics. Ciguatoxins (CTXs), ichthyosarcotoxins that cause ciguatera, produce a large peripheral sensitization to dynamic cold stimuli in Aδ-fibers by activating sodium channels without producing heat or mechanical allodynia.

Improved quantification of important beer quality parameters based on nonlinear calibration methods applied to FT-MIR spectra.

During the production process of beer, it is of utmost importance to guarantee a high consistency of the beer quality. For instance, the bitterness is an essential quality parameter which has to be controlled within the specifications at the beginning of the production process in the unfermented beer (wort) as well as in final products such as beer and beer mix beverages. Nowadays, analytical techniques for quality control in beer production are mainly based on manual supervision, i.

Cerebral Networks Linked to Itch-related Sensations Induced by Histamine and Capsaicin.

This functional magnetic resonance imaging (fMRI) study explored the central nervous processing of itch induced by histamine and capsaicin, delivered via inactivated cowhage spicules, and the influence of low-dose naltrexone. Scratch bouts were delivered at regular intervals after spicule insertion in order temporarily to suppress the itch. At the end of each trial the subjects rated their itch and scratch-related sensations.

Separating fusion from rivalry.

Visual fusion is the process in which differing but compatible binocular information is transformed into a unified percept. Even though this is at the basis of binocular vision, the underlying neural processes are, as yet, poorly understood. In our study we therefore aimed to investigate neural correlates of visual fusion.

Gender differences in itch and pain-related sensations provoked by histamine, cowhage and capsaicin.

Cowhage, capsaicin and histamine, all applied via spicules, were used to induce itch and pain-related sensations in 15 male and 15 female subjects. Sensory qualities were assessed by questionnaire; intensities and time courses of the "itching" and "burning" sensation were measured alternately, but continuously on a VAS. In addition, axon reflexes were assessed.

Effect of low-level laser therapy on blood flow and oxygen- hemoglobin saturation of the foot skin in healthy subjects: a pilot study.

Background And Aims: This study on healthy test subjects intends to show whether one-off Low-Level Laser Therapy (LLLT) has an instant effect on the perfusion or the oxygenation of the skin tissue. These possible instant effects may have an influence on the accelerated wound healing which is often observed after application of LLLT, in addition to the usual postulated effects of LLLT which occur with a time delay normally.

Study Design/materials And Methods: The study was carried out double-blind and placebo-controlled in two batches of testing.

CNS BOLD fMRI effects of sham-controlled transcutaneous electrical nerve stimulation in the left outer auditory canal - a pilot study.

Background: It has recently been shown that electrical stimulation of sensory afferents within the outer auditory canal may facilitate a transcutaneous form of central nervous system stimulation. Functional magnetic resonance imaging (fMRI) blood oxygenation level dependent (BOLD) effects in limbic and temporal structures have been detected in two independent studies. In the present study, we investigated BOLD fMRI effects in response to transcutaneous electrical stimulation of two different zones in the left outer auditory canal.

Central projection of pain arising from delayed onset muscle soreness (DOMS) in human subjects.

Delayed onset muscle soreness (DOMS) is a subacute pain state arising 24-48 hours after a bout of unaccustomed eccentric muscle contractions. Functional magnetic resonance imaging (fMRI) was used to examine the patterns of cortical activation arising during DOMS-related pain in the quadriceps muscle of healthy volunteers evoked by either voluntary contraction or physical stimulation. The painful movement or physical stimulation of the DOMS-affected thigh disclosed widespread activation in the primary somatosensory and motor (S1, M1) cortices, stretching far beyond the corresponding areas somatotopically related to contraction or physical stimulation of the thigh; activation also included a large area within the cingulate cortex encompassing posteroanterior regions and the cingulate motor area.

Differences and similarities on neuronal activities of people being happily and unhappily in love: a functional magnetic resonance imaging study.

Background: Brain activity was studied in grief following frustrated love compared to romantic love, and it was hypothesized that unhappy lovers compared to happy lovers would have decreased brain activity in regions specific to emotional and reward circuits, such as frontal brain areas, anterior cingulate cortex (ACC), bilateral insula or posterior cingulate cortex (PCC).

Methods: Twelve volunteers intensely in love and 12 volunteers recently separated from their romantic partners were scanned performing 3 runs of functional magnetic resonance imaging acquisition. Subjects viewed partner pictures versus erotic pictures during the first run of the scanning process, autobiographical pictures versus neutral pictures during the second and autobiographical texts versus neutral texts during the third run.

Cerebral representation of the relief of itch by scratching.

Cerebral processing of itch-scratching cycles was studied with functional magnetic resonance imaging (fMRI) in healthy volunteers. The back of the hand was repetitively scratched in the absence and presence of itch induced by histamine applied close to the scratched site. Blood-oxygenation-level-dependent (BOLD) effects were assessed in predefined cortical and subcortical brain regions of interest.

Bilateral brainstem activation by thermal stimulation of the face in healthy volunteers.

Contralateral sensory deficits in Wallenberg's lateral medullary syndrome suggest bilateral processing of trigeminal afferent input in the human brainstem. On the basis of experiments in rodents and clinical data, the present study addresses the hypothesis of bilateral projection of facial nociceptive input onto the spinal trigeminal nucleus (STN) in healthy humans. Nociceptive processing in the brainstem was investigated by functional magnetic resonance imaging (fMRI) in 18 healthy volunteers.

Impact of scratching on itch and sympathetic reflexes induced by cowhage (Mucuna pruriens) and histamine.

Cowhage and histamine, both applied via spicules, were used to induce itch. The quality and intensity of the sensations, axon reflex flare, sympathetic skin vasoconstrictions and the interference of scratching with itch processing were studied. Axon reflex flare reactions were measured by laser Doppler imaging and reflex vasoconstrictions in the finger were recorded by laser Doppler flowmetry.

Experimental tooth pain elevates substance P and matrix metalloproteinase-8 levels in human gingival crevice fluid.

Objective: Tooth pain can induce a neurogenic inflammatory reaction in gingiva in association with local elevations of matrix metalloproteinase (MMP)-8, which is considered the major tissue destructive protease in gingival crevice fluid (GCF). The pro-inflammatory neuropeptides released by sensory nerves coordinate the activities of the immuno-effector cells and may influence the secretion of MMP-8. With this background, we studied whether experimental tooth pain can trigger changes in GCF levels of the neuropeptide substance P (SP) and MMP-8.

Itch induced by a novel method leads to limbic deactivations a functional MRI study.

Functional brain imaging studies on itch usually use histamine as a stimulus and, in consequence, have to cope with the highly variable time course of this particular itch sensation. In this study, we describe a novel method of histamine application. To provoke itch, a mixture of histamine and codeine was applied through intradermally positioned microdialysis fiber.

The influence of simultaneous ratings on cortical BOLD effects during painful and non-painful stimulation.

This fMRI study investigates the influence of a rating procedure on BOLD signals in common pain-activated cortical brain regions. Painful and non-painful mechanical impact stimuli were applied to the left hand of healthy volunteers. Subjects performed ratings of the perceived intensity during every second stimulation period by operating a visual analogue scale with the right hand.

Brain activation during input from mechanoinsensitive versus polymodal C-nociceptors.

C-nociceptors mediating cutaneous pain in humans can be distinguished in mechano-heat-responsive units (CMH) and mechano-insensitive units (CMi). However, if sensitized in damaged tissue, CMi play an important role in inflammatory pain. CMi differ from CMH by higher electrical thresholds and by mediating the axon reflex.

Hypocapnia related changes in pain-induced brain activation as measured by functional MRI.

Stress, acute pain and chronic pain may often result in hyperventilation (HV) which produces hypocapnia. The aim of this fMRI-study was to investigate the influence of hypocapnia on cortical activation during noxious stimulation in 14 healthy volunteers. The intensity of voluntary HV was controlled by capnometry Three tasks were performed in the fMRI sessions: (I) three 3-min HV periods with 7-min periods of recovery in between; (II) mechanically induced phasic pain stimulation--pain task (PT); (III) tapping--motor task (MT).

Brain processing during mechanical hyperalgesia in complex regional pain syndrome: a functional MRI study.

Complex Regional Pain Syndromes (CRPS) are characterized by a triad of sensory, motor and autonomic dysfunctions of still unknown origin. Pain and mechanical hyperalgesia are hallmarks of CRPS. There are several lines of evidence that central nervous system (CNS) changes are crucial for the development and maintenance of mechanical hyperalgesia.

Neural activation during experimental allodynia: a functional magnetic resonance imaging study.

Abstract Pain induced by gentle stroking, i.e. dynamic-mechanical allodynia, is one of the most distressing symptoms of neuropathic pain.

Parameter estimation of human nerve C-fibers using matched filtering and multiple hypothesis tracking.

We describe how multiple-target tracking may be used to estimate conduction velocity changes and recovery constants of human nerve C-fibers. These parameters discriminate different types of C-fibers and pursuing this may promote new insights into differential properties of nerve fiber membranes. Action potentials (APs) were recorded from C-fibers in the peroneal nerve of awake human subjects.