Experimental muscle hyperalgesia modulates sensorimotor cortical excitability, which is partially altered by unaccustomed exercise

Impaired corticomotor function is reported in patients with lateral epicondylalgia, but the causal link to pain or musculotendinous overloading is unclear. In this study, sensorimotor cortical changes were investigated using a model of persistent pain combined with an overloading condition. In 24 healthy subjects, the effect of nerve growth factor (NGF)-induced pain, combined with delayed-onset muscle soreness (DOMS), was examined on pain perception, pressure pain sensitivity, maximal force, and sensorimotor cortical excitability. Two groups (NGF alone and NGF + DOMS) received injections of NGF into the extensor carpi radialis brevis (ECRB) muscle at day 0, day 2, and day 4. At day 4, the NGF + DOMS group undertook wrist eccentric exercise to induce DOMS in the ECRB muscle. Muscle soreness scores, pressure pain thresholds over the ECRB muscle, maximal grip force, transcranial magnetic stimulation mapping of the cortical ECRB muscle representation, and somatosensory-evoked potentials from radial nerve stimulation were recorded at day 0, day 4, and day 6. Compared with day 0, day 4 showed in both groups: (1) increased muscle soreness (P < 0.01); (2) reduced pressure pain thresholds (P < 0.01); (3) increased motor map volume (P < 0.01); and (4) decreased frontal N30 somatosensory-evoked potential. At day 6, compared with day 4, only the DOMS + NGF group showed: (1) increased muscle soreness score (P < 0.01); (2) decreased grip force (P < 0.01); and (3) decreased motor map volume (P < 0.05). The NGF group did not show any difference on the remaining outcomes from day 4 to day 6. These data suggest that sustained muscle pain modulates sensorimotor cortical excitability and that exercise-induced DOMS alters pain-related corticomotor adaptation

High frequency repetitive transcranial magnetic stimulation to the left dorsolateral prefrontal cortex modulates sensorimotor cortex function in the transition to sustained muscle pain

Based on reciprocal connections between the dorsolateral prefrontal cortex (DLPFC) and basal-ganglia regions associated with sensorimotor cortical excitability, it was hypothesized that repetitive transcranial magnetic stimulation (rTMS) of the left DLPFC would modulate sensorimotor cortical excitability induced by muscle pain. Muscle pain was provoked by injections of nerve growth factor (end of Day-0 and Day-2) into the right extensor carpi radialis brevis (ECRB) muscle in two groups of 15 healthy participants receiving 5 daily sessions (Day-0 to Day-4) of active or sham rTMS. Muscle pain scores and pressure pain thresholds (PPTs) were collected (Day-0, Day-3, Day-5). Assessment of motor cortical excitability using TMS (mapping cortical ECRB muscle representation) and somatosensory evoked potentials (SEPs) from electrical stimulation of the right radial nerve were recorded at Day-0 and Day-5. At Day-0 versus Day-5, the sham compared to active group showed: Higher muscle pain scores and reduced PPTs (P < 0.04); decreased frontal N30 SEP (P < 0.01); increased TMS map volume (P < 0.03). These results indicate that muscle pain exerts modulatory effects on the sensorimotor cortical excitability and left DLPFC rTMS has analgesic effects and modulates pain-induced sensorimotor cortical adaptations. These findings suggest an important role of prefrontal to basal-ganglia function in sensorimotor cortical excitability and pain processing

Macro remains of Chenopodium Quinoa willd from the Plaza of Laqaya site, Nor Lípez, Potosí, Bolivia

Se presentan análisis arqueobotánicos de macrorrestos carbonizados de quinoa recuperados al interior de una torre chullpa situada en la plaza central del sitio Laqaya (Potosí, Bolivia) y datada en los siglos xv-xvi. Con base en este hallazgo discutimos la participación de la quinoa en la vida política de los grupos prehispánicos tardíos del altiplano.This paper presents the analysis of archaeobotanical remains of quinoa found in a chullpa tower located in the main plaza of Laqaya, Potosí, Bolivia, a context dated to the fifteenth through sixteenth centuries. On the basis of this find, we discuss the role of quinoa in the political life of the late pre-Hispanic groups of the altiplano.Fil: Lopez, María Laura. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Antropología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nielsen, Axel Emil. Secretaría de Cultura de la Nación. Dirección Nacional de Cultura y Museos. Instituto Nacional de Antropología y Pensamiento Latinoamericano; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The Danish Veterinary and Food Administration’s Fight against Fake Nutrition News on Digital Media

This article examines fake nutrition news on digital media and the steps the Danish Veterinary and Food Administration (DVFA) are taking to counteract this development. Through a critical discourse analysis of four cases, we aim to shed light on the DVFA’s tactics to counteract the fake nutrition news phenomenon and discuss how the development of digital media has affected the spreading of fake news and alternate methods to combat fake news. The article concludes that the DVFA use discourses of responsibility and credibility to combat fake news and promote their strategy by establishing themselves as a credible source who consumers should trust.Denne artikel undersøger fake nutrition news på digitale medier, og hvordan Fødevarestyrelsen modarbejder denne udvikling. Gennem en kritisk diskursanalyse af fire cases ønsker vi at belyse Fødevarestyrelsens taktik til at modvirke fake news fænomenet og diskutere, hvordan udviklingen af digitale medier har påvirket spredningen af fake news samt alternative metoder til at bekæmpe fake news. Artiklen konkluderer, at Fødevarestyrelsen bruger ansvars- og troværdighedsdiskurser til at bekæmpe fake news og promovere deres strategi ved at fastsætte dem selv som en troværdig kilde, som forbrugere bør stole på