Effects of acute and sub-acute hypobaric hypoxia on oxidative stress: a field study in the Alps.

PURPOSE: High altitude results in lower barometric pressure and hence partial pressure of O2 decrease can lead to several molecular and cellular changes, such as generation of reactive oxygen species (ROS). Electron Paramagnetic Resonance technique was adopted in the field, to evaluate the effects of acute and sub-acute hypobaric hypoxia (HH) on ROS production by micro-invasive method. Biological biomarkers, indicators of oxidative stress, renal function and inflammation were investigated too. METHODS: Fourteen lowlander subjects (mean age 27.3 ± 5.9 years) were exposed to HH at 3269 m s.l. ROS production, related oxidative damage to cellular components, systemic inflammatory response and renal function were determined through blood and urine profile performed at 1st, 2nd, 4th, 7th, and 14th days during sojourn. RESULTS: Kinetics of changes during HH exposition showed out significant (range p < 0.05-0.0001) increases that at max corresponds to 38% for ROS production rate, 140% for protein carbonyl, 44% for lipid peroxidation, 42% for DNA damage, 200% for inflammatory cytokines and modifications in renal function (assessed by neopterin concentration: 48%). Conversely, antioxidant capacity significantly (p < 0.0001) decreased - 17% at max. CONCLUSION: This 14 days in-field study describes changes of oxidative-stress biomarkers during HH exposure in lowlanders. The results show an overproduction of ROS and consequent oxidative damage to protein, lipids and DNA with a decrease in antioxidant capacity and the involvement of inflammatory status and a transient renal dysfunction. Exposure at high altitude induces a hypoxic condition during acute and sub-acute phases accompanied by molecular adaptation mechanism indicating acclimatization.

P260Right cardiac chambers remodeling in marathon and ultra-trail athletes detected by speckle-tracking echocardiography.

BACKGROUND: Strenuous and chronic exercise training can have detrimental effects on cardiac morphology and function. Our aim was to evaluate the cardiac adaptation between 2 different specialties' endurance athletes: marathon runners (M) and ultra-trailers (UT). METHODS: 47 M (age 45±7, men 32; training: 18 (9-53) years*days/week), 41 UT (age 42±9, men 38, training: 30 (15-66) years*days/week) were submitted in rest condition to conventional 2D echocardiography and Speckle-Tracking echo (STE) (Beyond Diogenes 2.0, AMID) during agonistic season and compared with 15 age matched sedentary individuals (S) (age 43±6, men 10). RESULTS: Left ventricle (LV) global longitudinal strain (GLS) and global radial strain (GRS) were increased in M and UT compared to S (see table) without differences in LV anatomy and function. Right ventricle (RV) end-diastolic area (p=0.026), fractional area changing (p=0.008) and RV GLS were increased in UT compared to M. Moreover UT showed larger right atrium (RA) volume compared to M (p=0.03) and S (p=0.003). RA GLS was reduced in UT compared to M while the RA Global Circumferential Strain was significantly increased in UT. After adjusted for age, sex and HR as covariates, UT showed a reduced RA GLS (OR 0.907; CI 0.856-0.961) and increased RV FAC (OR 1.172; CI: 1.044-1.317) compared to M; while when compared to S subjects, UT showed increased RA volume (OR 1.048; CI 1.002-1.096) and RV GLS (OR 0.667; CI 0.490-0.907). CONCLUSION: UT showed higher RV and RA morphological and functional remodeling in comparison with M. 2D-STE is a useful tool to investigate the deformation dynamic in different sport specialties. Further studies will be necessary to clarify the long-term consequences for cardiac health due to myocardial perturbations.MUTSpLV GLS-28.59±3.43*-27.64±4.18*-24.82±4.53<0.05LV GRS69.85±8.94*66.59±11.19*56.27±16.25<0.001RV GLS-25.60±10.54-30.41±4.38*-27.10±4.64<0.05RA GLS37.15±13.4931.65±9.60*35.37±9.99<0.05RA GCS17.46±6.4222.28±8.97*23.37±6.47<0.01.

Gender-related differences in moral judgments.

The moral sense is among the most complex aspects of the human mind. Despite substantial evidence confirming gender-related neurobiological and behavioral differences, and psychological research suggesting gender specificities in moral development, whether these differences arise from cultural effects or are innate remains unclear. In this study, we investigated the role of gender, education (general education and health education) and religious belief (Catholic and non-Catholic) on moral choices by testing 50 men and 50 women with a moral judgment task. Whereas we found no differences between the two genders in utilitarian responses to non-moral dilemmas and to impersonal moral dilemmas, men gave significantly more utilitarian answers to personal moral (PM) dilemmas (i.e., those courses of action whose endorsement involves highly emotional decisions). Cultural factors such as education and religion had no effect on performance in the moral judgment task. These findings suggest that the cognitive-emotional processes involved in evaluating PM dilemmas differ in men and in women, possibly reflecting differences in the underlying neural mechanisms. Gender-related determinants of moral behavior may partly explain gender differences in real-life involving power management, economic decision-making, leadership and possibly also aggressive and criminal behaviors.

Modulation of beta oscillations in the subthalamic area during action observation in Parkinson's disease.

Mapping observed actions into the onlooker's motor system seems to provide the neurofunctional mechanisms for action understanding. Subthalamic nucleus (STN) local field potential (LFP) recordings in patients with movement disorders disclosed that network oscillations in the beta range are involved in conveying motor and non-motor information across the cortico-basal ganglia-thalamo-cortical loop. This evidence, together with the existence of connections between the STN and cortical areas active during observation of actions performed by other people, suggests that the STN oscillatory activity in specific frequency bands could encode not only motor information, but also information related to action observation. To test this hypothesis we directly recorded STN oscillations through electrodes for deep brain stimulation in patients with Parkinson's disease during observation of actions and of static objects. We found selective action-related oscillatory modulations in two functionally distinct beta bands: whereas low-beta oscillations (10-18 Hz) selectively desynchronized only during action-observation, high-beta oscillations (20-30 Hz) synchronized both during the observation of action and action-related objects. Low-beta modulations are therefore specific to action observation and high-beta modulations are related to the action scene. Our findings show that in the basal ganglia there are functional changes spreading to the action environment, probably presetting the motor system in relation to the motor context and suggesting that the dynamics of beta oscillations can contribute to action understanding mechanisms.

Transcranial direct current stimulation improves recognition memory in Alzheimer disease.

OBJECTIVE: To evaluate the cognitive effect of transcranial direct current stimulation (tDCS) over the temporoparietal areas in patients with Alzheimer disease (AD). METHODS: In 10 patients with probable AD, we delivered anodal tDCS (AtDCS), cathodal tDCS (CtDCS), and sham tDCS (StDCS) over the temporoparietal areas in three sessions. In each session recognition memory and visual attention were tested at baseline (prestimulation) and 30 minutes after tDCS ended (poststimulation). RESULTS: After AtDCS, accuracy of the word recognition memory task increased (prestimulation: 15.5 +/- 0.9, poststimulation: 17.9 +/- 0.8, p = 0.0068) whereas after CtDCS it decreased (15.8 +/- 0.6 vs 13.2 +/- 0.9, p = 0.011) and after StDCS it remained unchanged (16.3 +/- 0.7 vs 16.0 +/- 1.0, p = 0.75). tDCS left the visual attention-reaction times unchanged. CONCLUSION: Transcranial direct current stimulation (tDCS) delivered over the temporoparietal areas can specifically affect a recognition memory performance in patients with Alzheimer disease (AD). Because tDCS is simple, safe and inexpensive, our finding prompts studies using repeated tDCS, in conjunction with other therapeutic interventions for treating patients with AD.

Cerebellar transcranial direct current stimulation impairs the practice-dependent proficiency increase in working memory.

How the cerebellum is involved in the practice and proficiency of non-motor functions is still unclear. We tested whether transcranial direct current stimulation (tDCS) over the cerebellum (cerebellar tDCS) induces after-effects on the practice-dependent increase in the proficiency of a working memory (WM) task (Sternberg test) in 13 healthy subjects. We also assessed the effects of cerebellar tDCS on visual evoked potentials (VEPs) in four subjects and compared the effects of cerebellar tDCS on the Sternberg test with those elicited by tDCS delivered over the prefrontal cortex in five subjects. Our experiments showed that anodal or cathodal tDCS over the cerebellum impaired the practice-dependent improvement in the reaction times in a WM task. Because tDCS delivered over the prefrontal cortex induced an immediate change in the WM task but left the practice-dependent proficiency unchanged, the effects of cerebellar tDCS are structure-specific. Cerebellar tDCS left VEPs unaffected, its effect on the Sternberg task therefore seems unlikely to arise from visual system involvement. In conclusion, tDCS over the cerebellum specifically impairs the practice-dependent proficiency increase in verbal WM.

Lie-specific involvement of dorsolateral prefrontal cortex in deception.

Lies are intentional distortions of event knowledge. No experimental data are available on manipulating lying processes. To address this issue, we stimulated the dorsolateral prefrontal cortex (DLPFC) using transcranial direct current stimulation (tDCS). Fifteen healthy volunteers were tested before and after tDCS (anodal, cathodal, and sham). Two types of truthful (truthful selected: TS; truthful unselected: TU) and deceptive (lie selected: LS; lie unselected: LU) responses were evaluated using a computer-controlled task. Reaction times (RTs) and accuracy were collected and used as dependent variables. In the baseline task, the RT was significantly longer for lie responses than for true responses ([mean +/- standard error] 1153.4 +/- 42.0 ms vs. 1039.6 +/- 36.6 ms; F(1,14) = 27.25, P = 0.00013). At baseline, RT for selected pictures was significantly shorter than RT for unselected pictures (1051.26 +/- 39.0 ms vs. 1141.76 +/- 41.1 ms; F(1,14) = 34.85, P = 0.00004). Whereas after cathodal and sham stimulation, lie responses remained unchanged (cathodal 5.26 +/- 2.7%; sham 5.66 +/- 3.6%), after anodal tDCS, RTs significantly increased but did so only for LS responses (16.86 +/- 5.0%; P = 0.002). These findings show that manipulation of brain function with DLPFC tDCS specifically influences experimental deception and that distinctive neural mechanisms underlie different types of lies.

Improved naming after transcranial direct current stimulation in aphasia.

Transcranial direct current stimulation (tDCS) has been proposed as an adjuvant technique to improve functional recovery after ischaemic stroke. This study evaluated the effect of tDCS over the left frontotemporal areas in eight chronic non-fluent post-stroke aphasic patients. The protocol consisted of the assessment of picture naming (accuracy and response time) before and immediately after anodal or cathodal tDCS (2 mA, 10 minutes) and sham stimulation. Whereas anodal tDCS and sham tDCS failed to induce any changes, cathodal tDCS significantly improved the accuracy of the picture naming task by a mean of 33.6% (SEM 13.8%).

Gender-related differences in the human subthalamic area: a local field potential study.

The objective of this study was to investigate the possible existence of gender-related neurophysiological differences in the oscillatory activity of the human subthalamic area. To this end, we recorded local field potentials (LFPs) after neurosurgical procedures for deep brain stimulation (DBS) in 24 patients (12 males and 12 females) with Parkinson's disease. LFP recordings at rest before levodopa medication (19 nuclei from 11 female patients and 16 nuclei from ten male patients) showed significantly higher power in the alpha/low-beta band (8-12 Hz, P<0.01; 13-20 Hz, P=0.03) in females than in males. After levodopa medication (ten nuclei from six female patients and 11 nuclei from seven male patients), the power in the high-gamma band (60-90 Hz) and of the 300 Hz rhythm was significantly higher in females than in males (high-gamma, P=0.007; 300 Hz, P=0.002). These findings show that functional gender-related differences in the central nervous system involve the human subthalamic area (STN) and its response to levodopa in Parkinson's disease. Gender-related neurophysiological differences may be important for understanding gender-specific features of neurodegenerative disorders and should be considered when interpreting LFP data from the human basal ganglia.

Low-frequency subthalamic oscillations increase after deep brain stimulation in Parkinson's disease.

This work is the second of a series of papers in which we investigated the neurophysiological basis of deep brain stimulation (DBS) clinical efficacy using post-operative local field potential (LFP) recordings from DBS electrodes implanted in the subthalamic nucleus (STN) in patients with Parkinson's disease. We found that low-frequency (1-1.5Hz) oscillations in LFP recordings from the STN of patients with Parkinson's disease dramatically increase after DBS of the STN itself (log power change=0.93+/-0.62; Wilcoxon: p=0.0002, n=13), slowly decaying to baseline levels after turning DBS off. The DBS-induced increase of low-frequency LFP oscillations is highly reproducible and appears only after the delivery of DBS for a time long enough to induce clinical improvement. This increase of low-frequency LFP oscillations could reflect stimulation-induced modulation of network activity or could represent changes of the electrochemical properties at the brain-electrode interface.