Metabolic changes in concussed American football players during the acute and chronic post-injury phases

<p>Abstract</p> <p>Background</p> <p>Despite negative neuroimaging findings many athletes display neurophysiological alterations and post-concussion symptoms that may be attributable to neurometabolic alterations.</p> <p>Methods</p> <p>The present study investigated the effects of sports concussion on brain metabolism using ¹H-MR Spectroscopy by comparing a group of 10 non-concussed athletes with a group of 10 concussed athletes of the same age (mean: 22.5 years) and education (mean: 16 years) within both the acute and chronic post-injury phases. All athletes were scanned 1-6 days post-concussion and again 6-months later in a 3T Siemens MRI.</p> <p>Results</p> <p>Concussed athletes demonstrated neurometabolic impairment in prefrontal and motor (M1) cortices in the acute phase where NAA:Cr levels remained depressed relative to controls. There was some recovery observed in the chronic phase where Glu:Cr levels returned to those of control athletes; however, there was a pathological increase of m-I:Cr levels in M1 that was only present in the chronic phase.</p> <p>Conclusions</p> <p>These results confirm cortical neurometabolic changes in the acute post-concussion phase as well as recovery and continued metabolic abnormalities in the chronic phase. The results indicate that complex pathophysiological processes differ depending on the post-injury phase and the neurometabolite in question.</p

Troubles d'apprentissage au cégep: une nouvelle ressource pour comprendre et intervenir /

Tiré de l'écran-titre (visionné le 27 mars 2013)

Sensitivity to First- and Second-Order Drifting Gratings in 3-Month-Old Infants

In two experiments, we investigated 3-month-old infants' sensitivity to first- and second-order drifting gratings. In Experiment 1 we used forced-choice preferential looking with drifting versus stationary gratings to estimate depth modulation thresholds for 3-month-old infants and a similar task for a comparison group of adults. Thresholds for infants were more adult-like for second-order than first-order gratings. In Experiment 2, 3-month-olds dishabituated to a change in first-order orientation, but not to a change in direction of first- or second-order motion. Hence, results from Experiment 1 were likely driven by the perception of flicker rather than motion. Thus, infants' sensitivity to uniform motion is slow to develop and appears to be driven initially by flicker-sensitive mechanisms. The underlying mechanisms have more mature tuning for second-order than for first-order information

Orientation discrimination in 5-year-olds and adults tested with luminance-modulated and contrast-modulated gratings

We compared thresholds for discriminating orientation by 5-year-olds and adults for first-order (luminance-modulated) and second-order (contrast-modulated) gratings. To achieve equal visibility, we set the contrast for each age and condition at a fixed multiple of the contrast threshold for discriminating horizontal from vertical gratings. The minimum tilt that could be discriminated from vertical was four to five times larger in 5-year-olds than in adults, even when the noise was removed from the first-order stimuli and amplitude modulation increased to 0.90. Thresholds at both ages were significantly worse (1.2-1.5 times worse) for second-order modulation than for equally visible first-order modulation, and 5-year-olds were equally immature for both types of pattern. Together, the findings suggest that orientation discrimination is slow to develop and worse for second-order than first-order patterns in both children and adults

The effects of exercise during pregnancy on the newborn’s brain: study protocol for a randomized controlled trial

Abstract Background It is generally accepted that an active lifestyle is beneficial for cognition in children, adults and the elderly. Recently, studies using the rat animal model found that the pups of mothers who exercised during pregnancy had increased hippocampal neurogenesis and better memory and learning abilities. The aim of this report is to present the experimental protocol of a study that is designed to verify if an active lifestyle during pregnancy in humans has an impact on the newborn's brain. Methods 60 pregnant women will be included in a randomized controlled study. The experimental group will be asked to exercise a minimum of 20 minutes three times per week, at a minimal intensity of 55% of their maximal aerobic capacity. The control group will not be exercising. The effect of exercise during pregnancy on the newborn's brain will be investigated 8 to 12 days postpartum by means of the mismatch negativity, a neurophysiological brain potential that is associated to auditory sensory memory. We hypothesize that children born to mothers who exercised during their pregnancy will present shorter latencies and larger mismatch negativity amplitudes, indicating more efficient auditory memory processes. Discussion As of September 2011, 17 women have joined the study. Preliminary results show that the experimental group are active 3.1 ± 0.9 days per week while the control group only exercise 0.8 ± 0.6 days per week. The results of this study will present insight on fetal neuroplasticity and will be a valuable tool for health professionals who wish to encourage pregnant women to exercise. Trial registration ClinicalTrials.gov registration: NTC01220778</p

Influence of monocular deprivation during infancy on the later development of spatial and temporal vision

AbstractUsing the method of limits, we measured spatial and temporal vision in 15 patients, aged 4–28 years, who had been monocularly deprived of patterned visual input during infancy by a dense cataract. All patients showed losses in both spatial and temporal vision, with greater losses in spatial than in temporal vision. Losses were smaller when there had been more patching of the non-deprived eye. The results indicate that visual deprivation has smaller effects on the neural mechanisms mediating temporal vision than on those mediating spatial vision