A distributed brain response predicting the facial expression of acute nociceptive pain.

Pain is a private experience observable through various verbal and non-verbal behavioural manifestations, each of which may relate to different pain-related functions. Despite the importance of understanding the cerebral mechanisms underlying those manifestations, there is currently limited knowledge of the neural correlates of the facial expression of pain. In this functional magnetic resonance imaging (fMRI) study, noxious heat stimulation was applied in healthy volunteers and we tested if previously published brain signatures of pain were sensitive to pain expression.

A distributed brain response predicting the facial expression of acute nociceptive pain.

Pain is a private experience observable through various verbal and non-verbal behavioural manifestations, each of which may relate to different pain-related functions. Despite the importance of understanding the cerebral mechanisms underlying those manifestations, there is currently limited knowledge on the neural correlates of the facial expression of pain. In this functional magnetic resonance imaging (fMRI) study, noxious heat stimulation was applied in healthy volunteers and we tested if previously published brain signatures of pain were sensitive to pain expression.

Brain mechanisms associated with facial encoding of affective states.

Affective states are typically accompanied by facial expressions, but these behavioral manifestations are highly variable. Even highly arousing and negative valent experiences, such as pain, show great instability in facial affect encoding. The present study investigated which neural mechanisms are associated with variations in facial affect encoding by focusing on facial encoding of sustained pain experiences.

Brain responses to the vicarious facilitation of pain by facial expressions of pain and fear.

Observing pain in others facilitates self-pain in the observer. Vicarious pain facilitation mechanisms are poorly understood. We scanned 21 subjects while they observed pain, fear and neutral dynamic facial expressions.

Brain Responses to Hypnotic Verbal Suggestions Predict Pain Modulation.

The effectiveness of hypnosis in reducing pain is well supported by the scientific literature. Hypnosis typically involves verbal suggestions but the mechanisms by which verbal contents are transformed into predictive signals to modulate perceptual processes remain unclear. We hypothesized that brain activity during verbal suggestions would predict the modulation of responses to acute nociceptive stimuli.

Distinct fMRI patterns colocalized in the cingulate cortex underlie the after-effects of cognitive control on pain.

Demanding tasks can influence following behaviors but the underlying mechanisms remain largely unclear. In the present functional magnetic resonance imaging (fMRI) study, we used multivariate pattern analyses (MVPA) to compare patterns of brain activity associated with pain in response to noxious stimuli administered after a task requiring cognitive control (Stroop) and evaluate their functional interaction based on a mediation analysis model. We found that performing a difficult cognitive task leads to subsequent increases in pain and pain-related multivariate responses across the brain and within the anterior mid-cingulate cortex (aMCC).

Keeping an eye on pain expression in primary somatosensory cortex.

Facial expressions of pain are composed of a subset of pain-indicative muscle movements. Amongst this subset, contracting the muscles surrounding the eyes (orbicularis oculi muscle) is the most frequent response and has been linked specifically to pain intensity, a fundamental aspect of the sensory dimension of pain. To further explore this link, the present study used functional magnetic resonance imaging (fMRI) to test the hypothesis that orbicularis oculi activation during pain reflects the magnitude of brain responses in areas being involved in processing the sensory dimension of pain.

HYPNOTIC AUTOMATICITY IN THE BRAIN AT REST: An Arterial Spin Labelling Study.

The feeling of automaticity reported by individuals undergoing a hypnotic procedure is an essential dimension of hypnosis phenomenology. In the present study, healthy participants rated their subjective experience of automaticity and resting-state arterial spin labelling (ASL) scans were acquired before and after a standard hypnotic induction (i.e.

Correction: Test-retest reliability of myelin imaging in the human spinal cord: Measurement errors versus region- and aging-induced variations.

[This corrects the article DOI: 10.1371/journal.pone.

Test-retest reliability of myelin imaging in the human spinal cord: Measurement errors versus region- and aging-induced variations.

Purpose: To implement a statistical framework for assessing the precision of several quantitative MRI metrics sensitive to myelin in the human spinal cord: T1, Magnetization Transfer Ratio (MTR), saturation imposed by an off-resonance pulse (MTsat) and Macromolecular Tissue Volume (MTV).

Methods: Thirty-three healthy subjects within two age groups (young, elderly) were scanned at 3T. Among them, 16 underwent the protocol twice to assess repeatability.

Brain processing of the temporal dimension of acute pain in short-term memory.

The dynamics of noxious sensation shapes pain perception, yet the memory of the temporal dimension of pain remains almost completely unexplored. Here, brain activity during the memory of pain duration was contrasted with that associated with the memory of pain intensity using functional magnetic resonance imaging and a delayed reproduction task. Participants encoded, maintained during a short delay, and reproduced (1) the "duration" of pain (ie, onset-to-offset), (2) the "dynamics" of pain (ie, evolution of pain over time), or (3) the intensity of pain (ie, control with no explicit temporal processing required).

Thicker posterior insula is associated with disease duration in women with irritable bowel syndrome (IBS) whereas thicker orbitofrontal cortex predicts reduced pain inhibition in both IBS patients and controls.

Unlabelled: Patients with irritable bowel syndrome (IBS) are affected by chronic abdominal pain and show decreased pain inhibition. Moreover, they exhibit differences in brain morphology compared with healthy volunteers. The aim of this study was to examine whether decreased pain inhibition is associated with altered brain morphology in IBS patients.

Cerebral regulation of facial expressions of pain.

Facial expression of affective states plays a key role in social interactions. Interestingly, however, individuals differ substantially in their level of expressiveness, ranging from high expressive to stoic individuals. Here, we investigate which brain mechanisms underlie the regulation of facial expressiveness to acute pain.

Cerebral and spinal modulation of pain by emotions.

Emotions have powerful effects on pain perception. However, the brain mechanisms underlying these effects remain largely unknown. In this study, we combined functional cerebral imaging with psychophysiological methods to explore the neural mechanisms involved in the emotional modulation of spinal nociceptive responses (RIII-reflex) and pain perception in healthy participants.

Comparing functional connectivity via thresholding correlations and singular value decomposition.

We compare two common methods for detecting functional connectivity: thresholding correlations and singular value decomposition (SVD). We find that thresholding correlations are better at detecting focal regions of correlated voxels, whereas SVD is better at detecting extensive regions of correlated voxels. We apply these results to resting state networks in an fMRI dataset to look for connectivity in cortical thickness.

Differentiating noxious- and innocuous-related activation of human somatosensory cortices using temporal analysis of fMRI.

The role of the somatosensory cortices (SI and SII) in pain perception has long been in dispute. Human imaging studies demonstrate activation of SI and SII associated with painful stimuli, but results have been variable, and the functional relevance of any such activation is uncertain. The present study addresses this issue by testing whether the time course of somatosensory activation, evoked by painful heat and nonpainful tactile stimuli, is sufficient to discriminate temporal differences that characterize the perception of these stimulus modalities.