Social Touch Reduces Pain Perception-An fMRI Study of Cortical Mechanisms.

Unmyelinated low-threshold mechanoreceptors (C-tactile, CT) in the human skin are important for signaling information about hedonic aspects of touch. We have previously reported that CT-targeted brush stroking by means of a robot reduces experimental mechanical pain. To improve the ecological validity of the stimulation, we developed standardized human-human touch gestures for signaling attention and calming.

Robotic Stroking on the Face and Forearm: Touch Satiety and Effects on Mechanical Pain.

Slow stroking touch is generally perceived as pleasant and reduces thermal pain. However, the tactile stimuli applied tend to be short-lasting and typically applied to the forearm. This study aimed to compare the effects of a long-lasting brushing stimulus applied to the facial region and the forearm on pressure pain thresholds (PPTs) taken on the hand.

A potential role for two brainstem nuclei in craniovascular nociception and the triggering of migraine headache.

Aim: To use an animal model of migraine to test whether migraine headache might arise from a brainstem-trigeminal nucleus pathway.

Methods: We measured evoked and spontaneous activity of second-order trigeminovascular neurons in rats to test whether the activity of these neurons increased following the induction of cortical spreading depression or the imposition of light flash - two potential migraine triggers, or headache provokers. We then tested whether drugs that could activate, or inactivate, neurons of the nucleus raphe magnus or the periaqueductal gray matter, would affect any such increases selectively for the dura mater.

An ultrafast system for signaling mechanical pain in human skin.

The canonical view is that touch is signaled by fast-conducting, thickly myelinated afferents, whereas pain is signaled by slow-conducting, thinly myelinated ("fast" pain) or unmyelinated ("slow" pain) afferents. While other mammals have thickly myelinated afferents signaling pain (ultrafast nociceptors), these have not been demonstrated in humans. Here, we performed single-unit axonal recordings (microneurography) from cutaneous mechanoreceptive afferents in healthy participants.

Noxious, but not innocuous, thermal stimuli evoke pERK expression in dorsal horn neurons after spared nerve injury in adult rats.

Noxious stimulation of sensory afferents evokes phosphorylated extracellular signal regulated kinase (pERK) expression in spinal cord neurons. This study investigated the expression of pERK in the dorsal horn neurons in response to innocuous and noxious cold stimuli in naïve versus spared nerve injury (SNI) rats. Noxious cold or hot stimuli (0 or 45°C) elicited pERK expression in laminae I-II whereas cooling stimuli from 32°C to 25, 15 or 5°C produced no or little pERK expression in dorsal horn neurons.

Effect of dietary iodine on production of iodine enriched eggs.

Aim: Objective of this study was to investigate the effect of different levels of iodine supplementation on iodine content of eggs in laying hens.

Materials And Methods: In the experiment, 135 laying hens (White Leghorn) of 55 weeks age were randomly distributed to 5 dietary treatments; each group contained 27 laying hens distributed in three replicates of 9 birds each. Diet T1 was control basal layer diet without iodine enrichment in which iodine content (I2) was as per NRC recommendation.

Sensory perturbations using suture and sutureless repair of transected median nerve in rats.

The effects of changes to cold, mechanical, and heat thresholds following median nerve transection with repair by sutures (Su) or Rose Bengal adhesion (RA) were compared to sham-operated animals. Both nerve-injured groups showed a transient, ipsilateral hyposensitivity to mechanical and heat stimuli followed by a robust and long-lasting hypersensitivity (6-7 weeks) with gradual recovery towards pre-injury levels by 90 days post-repair. Both tactile and thermal hypersensitivity were seen in the contralateral limb that was similar in onset but differed in magnitude and resolved more rapidly compared to the injured limb.

Psychophysical Investigations into the Role of Low-Threshold C Fibres in Non-Painful Affective Processing and Pain Modulation.

We recently showed that C low-threshold mechanoreceptors (CLTMRs) contribute to touch-evoked pain (allodynia) during experimental muscle pain. Conversely, in absence of ongoing pain, the activation of CLTMRs has been shown to correlate with a diffuse sensation of pleasant touch. In this study, we evaluated (1) the primary afferent fibre types contributing to positive (pleasant) and negative (unpleasant) affective touch and (2) the effects of tactile stimuli on tonic muscle pain by varying affective attributes and frequency parameters.

Long term recovery of median nerve repair using laser-activated chitosan adhesive films.

Sutures remain the standard peripheral nerve repair technique, whether applied directly or indirectly to nerve tissue. Unfortunately, significant postoperative complications can result, such as inflammation, neuroma formation and foreign body reactions. Photochemical-tissue-bonding (PTB) using rose Bengal (RB) integrated into a chitosan bioadhesive is an alternative nerve repair device that removes the need for sutures.