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Two neuroimaging studies using functional magnetic resonance imaging (fMRI) and thermally induced pain are presented. Fifteen healthy right-handed subjects were imaged while they had to discern different levels of thermal stimuli in the first study and while they disengaged from the feeling of pain during constant stimulation in the second study. In the first experiment, during painful phasic stimuli, right-sided anterior insular activation as well as bilateral posterior insular activation could be shown regardless of stimulation side, as well as right-sided activation of sensory association areas in the superior parietal lobule. Also, activation of the ipsilateral sensorimotor cortex could be shown. In the second experiment, all subjects succeeded in suppressing the feeling of pain during previously painful levels of stimulation. During the early part of the tonic painful stimulation, bilateral activation of caudate head and dorsolateral prefrontal cortex (DLPFC) as well as insular cortex and dorsal anterior cingulated cortex (dACC) was observed. During the late part of the tonic painful stimulation, anterior insular activation as well as dACC and bilateral prefrontal cortical activation could be shown. Taken together, the activation of PFC and caudate nucleus hints at an important role in the initiation (caudate) and maintenance (PFC) of suppression of the feeling of pain. No ipsilateral sensorimotor activation could be shown in the second experiment. The possible import of unwanted sensorimotor activation due to the simultaneous rating process in the first experiment is discussed.

BackgroundThe TransEurope FootRace 2009 (TEFR09) was one of the longest transcontinental ultramarathons with an extreme endurance physical load of running nearly 4,500 km in 64 days. The aim of this study was to assess the wide spectrum of adaptive responses in humans regarding the different tissues, organs and functional systems being exposed to such chronic physical endurance load with limited time for regeneration and resulting negative energy balance. A detailed description of the TEFR project and its implemented measuring methods in relation to the hypotheses are presented.MethodsThe most important research tool was a 1.5 Tesla magnetic resonance imaging (MRI) scanner mounted on a mobile unit following the ultra runners from stage to stage each day. Forty-four study volunteers (67% of the participants) were cluster randomized into two groups for MRI measurements (22 subjects each) according to the project protocol with its different research modules: musculoskeletal system, brain and pain perception, cardiovascular system, body composition, and oxidative stress and inflammation. Complementary to the diverse daily mobile MR-measurements on different topics (muscle and joint MRI, T2*-mapping of cartilage, MR-spectroscopy of muscles, functional MRI of the brain, cardiac and vascular cine MRI, whole body MRI) other methods were also used: ice-water pain test, psychometric questionnaires, bioelectrical impedance analysis (BIA), skinfold thickness and limb circumference measurements, daily urine samples, periodic blood samples and electrocardiograms (ECG).ResultsThirty volunteers (68%) reached the finish line at North Cape. The mean total race speed was 8.35 km/hour. Finishers invested 552 hours in total. The completion rate for planned MRI investigations was more than 95%: 741 MR-examinations with 2,637 MRI sequences (more than 200,000 picture data), 5,720 urine samples, 244 blood samples, 205 ECG, 1,018 BIA, 539 anthropological measurements and 150 psychological questionnaires.ConclusionsThis study demonstrates the feasibility of conducting a trial based centrally on mobile MR-measurements which were performed during ten weeks while crossing an entire continent. This article is the reference for contemporary result reports on the different scientific topics of the TEFR project, which may reveal additional new knowledge on the physiological and pathological processes of the functional systems on the organ, cellular and sub-cellular level at the limits of stress and strain of the human body.Please see related articles: http://www.biomedcentral.com/1741-7015/10/76 and http://www.biomedcentral.com/1741-7015/10/77

Our experiments showed different cerebral processing of the feeling of nasal patency in ENS patients with prominent activation of areas belonging to the limbic system. The beneficial effect of menthol seems to correspond to activation differences in the temporal pole. These results demonstrate a neuronal substrate for both symptoms and their relief in ENS patients.

Personality profiles as well as pain tolerance of our sample of TEFR09 participants differ from normal controls and-as obtained in previous studies-probably also from chronic pain patients. Low pain perception may predispose a person to become a long-distance runner. It remains unclear, however, whether low pain perception is cause or consequence of continuous extreme training.