Sources of disconnection in neurocognitive aging: cerebral white-matter integrity, resting-state functional connectivity, and white-matter hyperintensity volume.

Age-related decline in fluid cognition can be characterized as a disconnection among specific brain structures, leading to a decline in functional efficiency. The potential sources of disconnection, however, are unclear. We investigated imaging measures of cerebral white-matter integrity, resting-state functional connectivity, and white-matter hyperintensity volume as mediators of the relation between age and fluid cognition, in 145 healthy, community-dwelling adults 19-79 years of age.

Frontoparietal activation during visual conjunction search: Effects of bottom-up guidance and adult age.

We conducted functional magnetic resonance imaging (fMRI) with a visual search paradigm to test the hypothesis that aging is associated with increased frontoparietal involvement in both target detection and bottom-up attentional guidance (featural salience). Participants were 68 healthy adults, distributed continuously across 19 to 78 years of age. Frontoparietal regions of interest (ROIs) were defined from resting-state scans obtained prior to task-related fMRI.

Age mediation of frontoparietal activation during visual feature search.

Activation of frontal and parietal brain regions is associated with attentional control during visual search. We used fMRI to characterize age-related differences in frontoparietal activation in a highly efficient feature search task, detection of a shape singleton. On half of the trials, a salient distractor (a color singleton) was present in the display.

The persistence of distraction: a study of attentional biases by fear, faces, and context.

Efficient processing of the visual world requires that distracting items be avoided, or at least rapidly disengaged from. The mechanisms by which highly salient, yet irrelevant, stimuli lead to distraction, however, are not well understood. Here, we utilized a particularly strong type of distractor--images of human faces--to investigate the mechanisms of distraction and the involuntarily biasing of attention.

Brain connectivity and visual attention.

Emerging hypotheses suggest that efficient cognitive functioning requires the integration of separate, but interconnected cortical networks in the brain. Although task-related measures of brain activity suggest that a frontoparietal network is associated with the control of attention, little is known regarding how components within this distributed network act together or with other networks to achieve various attentional functions. This review considers both functional and structural studies of brain connectivity, as complemented by behavioral and task-related neuroimaging data.

Isolating the internal in endogenous attention.

Neuroimaging studies have provided evidence that a bilateral frontal-parietal network is involved in voluntary attentional control. However, because those studies used instructive cue stimuli, some of the activity may have been due to interactions between cue processing and voluntary orienting. Here, we show that self-initiated voluntary orienting, in the absence of any cue stimulus, evokes activity in this frontal-parietal network.

Hold it! Memory affects attentional dwell time.

The allocation of attention, including the initial orienting and the subsequent dwell time, is affected by several bottom-up and top-down factors. How item memory affects these processes, however, remains unclear. Here, we investigated whether item memory affects attentional dwell time by using a modified version of the attentional blink (AB) paradigm.