Neuroimaging studies of healthy aging often reveal differences in neural activation patterns between young and elderly groups for episodic memory tasks, even though there are no differences in behavioral performance. One explanation typically offered is that the elderly compensate for their memory deficiencies through the recruitment of additional prefrontal regions. The present study of healthy aging compared magnetoencephalographic (MEG) time-courses localized to specific cortical regions in two groups of subjects (20-29 years and ≥65 years) during a visual delayed-match-to-sample (DMS) task. MR morphometrics and neuropsychological test results were also examined with the hope of providing insight into the nature of the age-related differences. The behavioral results indicated no differences in performance between young and elderly groups. Although there was a main effect of age on the latency of the initial peak in primary/secondary visual cortex, these longer latencies were not correlated with the performance of elderly on the DMS task. The lateral occipital gyrus (LOG) revealed qualitatively different patterns of activity for the two age groups corroborated by neuropsychological test results. Morphometric results for the young versus elderly groups revealed less white (WM) and gray matter (GM) volumes in the frontal lobes of the elderly. When a group of middle-aged subjects (33-43 years) was included in the morphometric analyses, the middle-aged subjects revealed statistically greater WM volumes in frontal and parietal cortex suggesting immature WM tracts in the young. Perhaps our elderly utilized a different strategy compared to the young due to the different brain maturation levels of these groups.

Methanol poisonings continue to occur in the United States with toddlers at the highest risk for exposure, but adolescents and adults at the highest risk for life-threatening intoxications. Over half of product-identified cases were due to consumption of windshield wiperfluid. Efforts should be undertaken to minimize methanol exposures.

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Articles you may be interested inAtomic layer deposited beryllium oxide: Effective passivation layer for III-V metal/oxide/semiconductor devices J. Appl. Phys. 109, 064101 (2011); 10.1063/1.3553872Pulse response of thin III/V semiconductor photocathodes A simple procedure for the rapid formation of uniform native oxides on various III-V semiconductor materials is described. A puIsed applied potential drives an anodic oxide formation process on the semiconductor immersed in a glycol:water:acid solution. Uniform oxides up to 2000 A thick can be grown in a few minutes at room temperature and used to define areas for current injection into the semiconductor. AlGaAs diode lasers fabricated with 50-pm-wide current stripes defined by pulsed anodic oxide had threshold current densities substantially lower than lasers fabricated with 50-,um-wide stripes defined by chemical-vapor-deposited SiO,.

We used magnetoencephalography in combination with magnetic resonance imaging to investigate the effects of aging on the temporal dynamics of activity localized to several brain regions during an auditory oddball task. The most interesting effects were noted in the superior temporal gyrus as follows: (1) responses were generally stronger to rare than to frequent tones throughout the entire 600-ms time interval, and (2) increases in the amplitude of the 40-ms peak and the latency of the maximum late response were evident in the elderly. Although superior temporal gyrus activity has traditionally been associated with early sensory processing, these results suggest that superior temporal gyrus activity is also important for later decision-related processing.