Cognitive Status and Nutritional Markers in a Sample of Institutionalized Elderly People.

Background: Since many of the risk factors for cognitive decline can be modified by diet, the study of nutrition and its relationships with cognitive status in aging has increased considerably in recent years. However, there are hardly any studies that have assessed cognitive status using a comprehensive set of neuropsychological tests along with measures of functional capacity and mood and that have related it to nutritional status measured from several nutritional parameters that have shown its relationships with cognitive function.

Objective: To test the differences in depressive symptomatology and in several measures of nutritional status between three groups classified according to their cognitive status (CS hereafter).

Attentional Modulation of Change Detection ERP Components by Peripheral Retro-Cueing.

Change detection is essential for visual perception and performance in our environment. However, observers often miss changes that should be easily noticed. A failure in any of the processes involved in conscious detection (encoding the pre-change display, maintenance of that information within working memory, and comparison of the pre and post change displays) can lead to change blindness.

Preserved Suppression of Salient Irrelevant Stimuli During Visual Search in Age-Associated Memory Impairment.

Previous studies have suggested that older adults with age-associated memory impairment (AAMI) may show a significant decline in attentional resource capacity and inhibitory processes in addition to memory impairment. In the present paper, the potential attentional capture by task-irrelevant stimuli was examined in older adults with AAMI compared to healthy older adults using scalp-recorded event-related brain potentials (ERPs). ERPs were recorded during the execution of a visual search task, in which the participants had to detect the presence of a target stimulus that differed from distractors by orientation.

Vertical asymmetries and inhibition of return: effects of spatial and non-spatial cueing on behavior and visual ERPs.

The mechanisms underlying inhibition of return (IOR) are still under debate. Besides the probable implication of several processes in its generation, a reason for this uncertainty may be related to experimental factors affecting the presence, time course, and magnitude of IOR. Two of them may be related to the arrangement of the stimuli in the visual field that could cause possible interactions between IOR and response conflict effects (horizontal arrangements) or between IOR and perceptual asymmetries (vertical arrangement).

Response processing during visual search in normal aging: the need for more time to prevent cross talk between spatial attention and manual response selection.

It is still not well known whether the age-related behavioural slowing observed during visual search is due to changes in the allocation of attention, in response activation patterns, or to a combination of both. To help in clarifying it, attention-related (N2 posterior contralateral; N2pc, and N2 central contralateral; N2cc) and response-related (Motor Potential; MP, and Reafferent Potential; RAP) event-related potentials (ERPs) were obtained in healthy young and older participants executing a visual search task. Age was associated with N2pc and N2cc longer latencies, earlier MP onsets and longer MP rise times.

Oscillatory brain activity in the time frequency domain associated to change blindness and change detection awareness.

Despite the importance of change detection (CD) for visual perception and for performance in our environment, observers often miss changes that should be easily noticed. In the present study, we employed time-frequency analysis to investigate the neural activity associated with CD and change blindness (CB). Observers were presented with two successive visual displays and had to look for a change in orientation in any one of four sinusoid gratings between both displays.

Neural correlates of age-related visual search decline: a combined ERP and sLORETA study.

Differences in the neural systems underlying visual search processes for young (n=17, mean age 19.6+/-1.9) and older (n=22, mean age 68.

Feature processing during visual search in normal aging: electrophysiological evidence.

Event-related potentials (ERPs) were recorded from healthy young and older subjects during the execution of a visual search task in which they were required to detect the presence of a target stimulus that differed from distractors in a salient feature (orientation). Apart from the orientation target, a task-irrelevant singleton defined by a different feature (color) was also presented without instruction. The effects of normal aging on the N2pc component, an electrophysiological correlate of the allocation of visuospatial attention, were evaluated for the first time.

Vertical asymmetries in pre-attentive detection of changes in motion direction.

Stimulus localization affects visual motion processing. Vertical asymmetries favouring lower visual field have been reported in event-related potentials (ERPs) and behavioural studies under different attention conditions. However, there are no studies examining such asymmetries to non-attended motion changes.

Cognitive reserve, age, and neuropsychological performance in healthy participants.

The first aim of this study was to explore the relation between cognitive reserve, age, and neuropsychological functioning in a healthy sample; and second, to determine the risk of showing cognitive deficits as a function of cognitive reserve. One hundred forty-six healthy participants between the ages of 20 and 79 were submitted to neuropsychological assessment, focusing on attention, memory, visuo-construction, conceptualization and reasoning. Premorbid IQ as measured with the Wechsler Adult Intelligence Scale Vocabulary subtest was used as a proxy of cognitive reserve.

Pre-attentive detection of motion direction changes in normal aging.

Effects of normal aging on pre-attentive detection of changes in motion direction were evaluated. Young, middle-aged, and older subjects performed a visual central task while standard and deviant gratings varying in motion direction were presented outside the focus of attention. A greater negativity in the event-related potentials (ERPs) to deviants was observed in all groups at posterior sites within the N2 latency range.

Effects of stimulus location on automatic detection of changes in motion direction in the human brain.

We extended the results of a previous report by further exploring the underlying mechanisms of an electrophysiological index of attention-free memory-based detection mechanism to motion-direction changes in the human visual system. By means of presenting bilateral, right- and left-hemifield stimulation in separate conditions, we tried to assess whether the location of the stimuli within the peripheral visual field affected the processing of motion-direction deviations, and to identify brain regions involved in the detection of unattended infrequent changes of motion direction using low-resolution brain electromagnetic tomography (LORETA). Results indicated that the ERP component related to visual change was not affected by stimulus location, and that bilateral temporal and medial regions were activated during this deviance-related response regardless of the hemifield stimulated.

Covert orienting of visuospatial attention in the early stages of aging.

Electrophysiological and behavioral responses were recorded in healthy young (19-23 years) and older (56-66 years) subjects during the execution of a visuospatial attention task. The objective was to test whether covert orienting of visuospatial attention (COVAT) is sensitive to the early stages of aging. All subjects responded faster to targets following valid than invalid cues.