Neuroanatomical correlates of aging, cardiopulmonary fitness level, and education.

Fitness and education may protect against cognitive impairments in aging. They may also counteract age-related structural changes within the brain. Here we analyzed volumetric differences in cerebrospinal fluid and gray and white matter, along with neuropsychological data, in adults differing in age, fitness, and education.

Effects of measurement method, wavelength, and source-detector distance on the fast optical signal.

Fast optical signals can be used to study the time course of neuronal activity in localized cortical areas. The first report of such signals [Gratton, G., Corballis, P.

Putting things into perspective: individual differences in working-memory span and the integration of information.

An important function of working memory is the integration of incoming information into an appropriate model of the contextual situation. We hypothesized that individual variability in working-memory function (estimated using Engle's operation-span measure) may lead to differential reactivity to a changing context. We recorded event-related brain potentials (ERPs) and reaction-time measures to stimuli embedded in long stimulus series (two auditory discrimination tasks), and examined the participants' responses in relation to how the current stimuli fit with the context generated by the previous stimuli.

Sensory ERPs predict differences in working memory span and fluid intelligence.

The way our brain reacts to sensory stimulation may provide important clues about higher-level cognitive function and its operation. Here we show that short-latency (< 200 ms) sensory cortical responses elicited by visual and auditory stimuli differ dramatically between subjects with high and low working-memory span, as well as between subjects scoring high and low on a fluid intelligence test. Our findings also suggest that this link between sensory responses and complex cognitive tasks is modality specific (visual sensory measures correlate with visuo-spatial tasks whereas auditory sensory measures correlate with verbal tasks).