Search results for " Stimulus"
showing 10 items of 75 documents
Clinical evaluation criteria for the assessment of impaired pain sensitivity by thulium-laser evoked potentials
2000
Abstract Objectives : Cortical potentials evoked by carbon dioxide laser pulses have been applied in clinical practice to study nociceptive pathways for several years. In this study, we evaluate the properties of an infrared laser (thulium-YAG) with a penetration depth in the skin that matches the intracutaneous depth of nociceptors. Methods : Temperature measurements and modelling showed that the thulium laser generates painful intracutaneous temperatures with less surface heating than the carbon dioxide laser and with no side effects (up to 600 mJ pulse energy). To develop clinical evaluation criteria, laser-evoked potentials (LEPs) were recorded from 3 midline positions (Fz, Cz, Pz) vers…
Persistent antinociception through repeated self-injury in patients with borderline personality disorder.
2012
Abstract Patients with borderline personality disorder, mostly female, exhibit severe autoaggressive behavior, namely an intentionally performed, nonsuicidal self-injury and severe blunting of pain perception, the mechanism of which is hitherto not understood. Because the nociceptive system displays a high degree of plasticity, the aim of this study was to analyze the relationship of pain perception to self-injurious behavior. Pain perception of mechanical and chemical noxious stimuli was studied by quantitative sensory testing in 22 patients (15 female, 7 male) with borderline personality disorder (BPD) according to DSM-IV and 22 age- and gender-matched controls. BPD patients exhibited a s…
Psychophysics, flare, and neurosecretory function in human pain models: capsaicin versus electrically evoked pain.
2007
Intradermal capsaicin injection (CAP) and electrical current stimulation (ES) are analyzed in respect to patterns and test-retest reliability of pain as well as sensory and neurosecretory changes. In 10 healthy subjects, 2 CAP (50 g) and 2 ES (5 to 30 mA) were applied to the volar forearm. The time period between 2 identical stimulations was about 4 months. Pain ratings, areas of mechanical hyperalgesia, and allodynia were assessed. The intensity of sensory changes was quantified by using quantitative sensory testing. Neurogenic flare was assessed by using laser Doppler imaging. Calcito- nin gene-related peptide (CGRP) release was quantified by dermal microdialysis in combination with an en…
Effects of instruction on acquisition and extinction of electrodermal responses to fear-relevant stimuli.
1977
In the present study we examined the hypothesis that electrodermal responses conditioned to fear-relevant stimuli are insensitive to verbal instructions. In the first experiment, different groups of subjects were conditioned to fear-relevant and fear-irrelevant control stimuli in a long interstimulus interval differential paradigm with shock as the unconditioned stimulus. Then half of the subjects were informed that no more shocks would be presented, and a number of extinction trials followed. The instruction completely abolished responding to fear-irrelevant stimuli, while leaving responses to the fear-relevant stimuli unaffected. In the second experiment, subjects were "conditioned" to fe…
Do Intensity Ratings and Skin Conductance Responses Reliably Discriminate Between Different Stimulus Intensities in Experimentally Induced Pain?
2010
Abstract The present study addresses the question whether pain-intensity ratings and skin conductance responses (SCRs) are able to detect different intensities of phasic painful stimuli and to determine the reliability of this discrimination. For this purpose, 42 healthy participants of both genders were assigned to either electrical, mechanical, or laser heat-pain stimulation (each n = 14). A whole range of single brief painful stimuli were delivered on the right volar forearm of the dominant hand in a randomized order. Pain-intensity ratings and SCRs were analyzed. Using generalizability theory, individual and gender differences were the main contributors to the variability of both intens…
Differential effects on the laser evoked potential of selectively attending to pain localisation versus pain unpleasantness
2004
Abstract Objective : To determine the effects on the laser evoked potential (LEP) of selectively attending to affective (unpleasantness) versus sensory-discriminative (localisation) components of pain. Methods : LEPs, elicited by painful CO 2 laser stimulation of two areas of the right forearm, were recorded from 62 electrodes in 21 healthy volunteers, during three tasks that were matched for generalised attention: Localisation (report stimulus location), Unpleasantness (report stimulus unpleasantness), Control (report pain detection). LEP components are named by polarity, latency, and electrode. Results : N300-T7 peak amplitude was significantly greater during Localisation than Unpleasantn…
Thinking about movement hurts: The effect of motor imagery on pain and swelling in people with chronic arm pain
2008
Objective: Chronic painful disease is associated with pain on movement, which is presumed to be caused by noxious stimulation. We investigated whether motor imagery, in the absence of movement, increases symptoms in patients with chronic arm pain. Methods: Thirty‐seven subjects performed a motor imagery task. Pain and swelling were measured before, after, and 60 minutes after the task. Electromyography findings verified no muscle activity. Patients with complex regional pain syndrome (CRPS) were compared with those with non‐CRPS pain. Secondary variables from clinical, psychophysical, and cognitive domains were related to change in symptoms using linear regression. Results: Motor imagery in…
Differential nociceptive deficits in patients with borderline personality disorder and self-injurious behavior: laser-evoked potentials, spatial disc…
2003
Approximately 70-80% of women meeting criteria for borderline personality disorder (BPD) report attenuated pain perception or analgesia during non-suicidal, intentional self-mutilation. The aim of this study was to use laser-evoked potentials (LEPs) and psychophysical methods to differentiate the factors that may underlie this analgesic state. Ten unmedicated female patients with BPD (according to DSM-IV) and 14 healthy female control subjects were investigated using brief radiant heat pulses generated by a thulium laser and five-channel LEP recording. Heat pulses were applied as part of a spatial discrimination task (two levels of difficulty) and during a mental arithmetic task. BPD patien…
Context, remember–know recognition judgements, and ROC parameters
2007
Recent work (e.g., Dunn, 2004; Heathcote, 2003) has questioned the necessity of postulating two processes to explain recognition memory. As part of this trend, strength theories of the remember-know methodology have gained in support. We present three experiments with pictorial material in which we force participants to use differential contextual information at test. Participants were required to give remember-know judgements and confidence ratings for each test stimulus. Hits, false alarms, remember-know data, and discrimination indices indicated systematic variations as a function of the availability and use of contextual information. Moreover, when we normalised the receiver operating c…
Dynamics of the general factor of personality: A predictor mathematical tool of alcohol misuse
2020
[EN] There are few studies developed about the general factor of personality (GFP) dynamics. This paper uses a dynamical mathematical model, the response model, to predict the short-term effects of a dose of alcohol on GFP and reports the results of an alcohol intake experiment. The GFP dynamical mechanism of change is based on the unique trait personality theory (UTPT). This theory proposes the existence of GFP, which occupies the apex of the hierarchy of personality. An experiment with 37 volunteers was performed. All the participants completed The five-adjective scale of the general factor of personality (GFP-FAS) in trait-format (GFP-T) and state-format (GFP-S) before alcohol consumptio…