Amygdala responses to emotionally valenced stimuli in older and younger adults

ABSTRACT—As they age, adults experience less negative emotion, come to pay less attention to negative than to positive emotional stimuli, and become less likely to remember negative than positive emotional materials. This profile of findings suggests that, with age, the amygdala may show decreased reactivity to negative information while maintaining or increasing its reactivity to positive information. We used event-related functional magnetic resonance imaging to assess whether amygdala activation in response to positive and negative emotional pictures changes with age. Both older and younger adults showed greater activation in the amygdala for emotional than for neutral pictures; however, for older adults, seeing positive pictures led to greater amygdala activation than seeing negative pictures, whereas this was not the case for younger adults. Older adults experience less negative affect than younger adults in both cross-sectional and longitudinal studies (Carstensen, Pasupathi

A direct test of the unequal-variance signal detection model of recognition memory

Analyses of the receiver operating characteristic (ROC) almost invariably suggest that, on a recognition memory test, the standard deviation of memory strengths associated with the lures (sigma(lure)) is smaller than that of the targets (sigma(target)). Often, sigma(lure)/ sigma(target) approximately = 0.80. However, that conclusion is based on a model that assumes that the memory strength distributions are Gaussian in form. In two experiments, we investigated this issue in a more direct way by asking subjects to simply rate the memory strengths of targets and lures using a 20-point or a 99-point strength scale. The results showed that the standard deviation of the ratings made to the targets (S(target)) was, indeed, larger than the standard deviation of the ratings made to the lures (S(lure)). Moreover, across subjects, the ratio S(lure)/ S(target) correlated highly with the estimate of sigma(lure)/ sigma(target) obtained from ROC analysis, and both estimates were, on average, approximately equal to 0.80.</p

The limited usefulness of models based on recollection and familiarity.

A recent report concluded that magnetoencephalographic signals of neural activity associated with memory based on the recollection process are independent from signals associated with memory based on the familiarity process. These data can be interpreted equally well, however, as indications of memory aggregated from both processes and showing that signals associated with high-confidence recognition are dissociable from signals associated with low-confidence recognition. The usefulness of interpreting neural data according to psychological models based on recollection and familiarity is discussed

The limited usefulness of models based on recollection and familiarity.

A recent report concluded that magnetoencephalographic signals of neural activity associated with memory based on the recollection process are independent from signals associated with memory based on the familiarity process. These data can be interpreted equally well, however, as indications of memory aggregated from both processes and showing that signals associated with high-confidence recognition are dissociable from signals associated with low-confidence recognition. The usefulness of interpreting neural data according to psychological models based on recollection and familiarity is discussed

External distraction impairs categorization performance in older adults.

The detrimental influence of distraction on memory and attention is well established, yet it is not as clear if irrelevant information impacts categorization abilities and if this impact changes in aging. We examined categorization with morphed prototype stimuli in both younger and older adults, using an adaptive staircase approach to assess participants' performance in conditions with and without visual distractors. Results showed that distraction did not affect younger adults, but produced a negative impact on older adults' categorization such that there was an interaction of age and distraction. These results suggest a relationship between the increased susceptibility to visual distraction in normal aging and impairment in categorization

External distraction impairs categorization performance in older adults.

The detrimental influence of distraction on memory and attention is well established, yet it is not as clear whether irrelevant information impacts categorization abilities and whether this impact changes in aging. We examined categorization with morphed prototype stimuli in both younger and older adults, using an adaptive staircase approach to assess participants' performance in conditions with and without visual distractors. Results showed that distraction did not affect younger adults, but produced a negative impact on older adults' categorization such that there was an interaction of age and distraction. These results suggest a relationship between the increased susceptibility to visual distraction in normal aging and impairment in categorization