Age-group differences in medial cortex activity associated with thinking about self-relevant agendas.

In this functional magnetic resonance imaging (fMRI) study, we compared young and older adults’ brain activity as they thought about motivationally self-relevant agendas (hopes and aspirations, duties and obligations) and concrete control items (e.g., shape of USA). Young adults’ activity replicated a double dissociation (M. K. Johnson et al., 2006): An area of medial frontal gyrus/anterior cingulate cortex was most active during hopes and aspirations trials, and an area of medial posterior cortex—primarily posterior cingulate—was most active during duties and obligations trials. Compared with young adults, older adults showed attenuated responses in medial cortex, especially in medial prefrontal cortex, with both less activity during self-relevant trials and less deactivation during control trials. The fMRI data, together with post-scan reports and the behavioral literature on age-group differences in motivational orientation, suggest that the differences in medial cortex seen in this study reflect young and older adults’ focus on different information during motivationally self-relevant thought. Differences also may be related to an age-associated deficit in controlled cognitive processes that are engaged by complex self-reflection and mediated by prefrontal cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do young and older adults rely on different processes in source memory tasks? A neuropsychological study.

Source memory has consistently been associated with prefrontal function in both normal and clinical populations. Nevertheless, the exact contribution of this brain region to source memory remains uncertain, and evidence suggests that processes used by young and older adults may differ. The authors explored the extent to which scores on composite measures of neuropsychological tests of frontal and medial temporal function differentially predicted the performance of young and older adults on source memory tasks. Results indicated that a frontal composite measure, consistently associated with source memory performance in older adults, was unrelated to source memory in young adults, although it was sensitive to a demanding working memory task. The memory composite score, however, predicted performance in the young group. In addition, item and source memory were correlated in young but not older people. Findings are discussed in terms of age-related differences in working memory and executive functions, and differential binding processes necessary for item and source memory. The requirement to integrate item and source information at encoding appears to place greater demands on executive or working memory processes in older adults than in younger adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging minds and twisting attitudes: An fMRI investigation of age differences in inhibiting prejudice.

Cognitive capacity is believed to decline with age, but it is not known whether this decline extends to tasks involving social cognition. In the current study, social neuroscience methodologies were used to examine the effects of age-related cognitive decline on older adults’ abilities to engage regulatory mechanisms (which are typically impaired by normal aging) to inhibit negative reactions to stigmatized individuals. Older and young adults were presented with images of stigmatized individuals (e.g., individuals with amputations, substance abusers) and of normal controls while they underwent functional magnetic resonance imaging. All participants were also given a battery of tests to assess their executive function capacity. Young adults showed more activity in areas associated with empathy (i.e., medial prefrontal cortex) than did older adults when viewing stigmatized faces. By contrast, older adults with relatively preserved levels of executive function had heightened activity in areas previously implicated in emotion regulation (i.e., lateral prefrontal cortex) as compared to other groups. These results suggest that although cognitive decline may interfere with older adults’ attitudes toward stigmatized individuals, older adults with relatively preserved cognitive function may utilize different strategies to compensate for these deficits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Implications of Cortical Recruitment and Brain Morphology for Individual Differences in Inhibitory Function in Aging Humans.

The authors assessed individual differences in cortical recruitment, brain morphology, and inhibitory task performance. Similar to previous studies, older adults tended toward bilateral activity during task performance more than younger adults. However, better performing older adults showed less bilateral activity than poorer performers, contrary to the idea that additional activity is universally compensatory. A review of the results and of extant literature suggests that compensatory activity in prefrontal cortex may only be effective if the additional cortical processors brought to bear on the task can play a complementary role in task performance. Morphological analyses revealed that frontal white matter tracts differed as a function of performance in older adults, suggesting that hemispheric connectivity might impact both patterns of recruitment and cognitive performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and single versus multiple cues in source monitoring.

Participants heard words said by 2 speakers and later decided who said each word. The authors varied the perceptual distinctiveness of the speakers and the distinctiveness of the cognitive operations participants performed on the words. Relative to younger adults, older adults had significantly lower source monitoring scores when perceptual or cognitive operations conditions were similar but not when either cue was more distinctive. Combining cues did not affect source monitoring of younger adults but hurt older adults' performance relative to the distinctive perceptual condition. Evidently, older adults generate cognitive cues at the expense of encoding perceptual cues; any deficit in binding perceptual and semantic information disadvantages them more in source monitoring than in old/new recognition. There was no correlation between neuropsychological tests assessing frontal function and source monitoring in older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

True and false memories in children and adults: A cognitive neuroscience perspective.

The authors consider evidence concerning accuracy and distortion in children's recollections within the broader context of recent research on memory that has used the methods and conceptual framework of cognitive neuroscience. They focus on 3 phenomena (source amnesia, confabulation, and false recognition) that have been observed in young children and in adults who have sustained damage to the frontal lobes. Similarities and differences between the memory performance of young children and frontal lobe patients are noted, and evidence concerning frontal lobe maturation and cognitive development is examined. The literature provides suggestive but not conclusive support for the hypothesis that some aspects of memory development and cognitive development are associated with immature frontal functioning. The authors conclude by considering several cognitive and temperamental factors that may be related to suggestibility and memory distortion in young children. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Differential effects of age on involuntary and voluntary autobiographical memory.

Research on aging and autobiographical memory has focused almost exclusively on voluntary autobiographical memory. However, in everyday life, autobiographical memories often come to mind spontaneously without deliberate attempt to retrieve anything. In the present study, diary and word-cue methods were used to compare the involuntary and voluntary memories of 44 young and 38 older adults. The results showed that older adults reported fewer involuntary and voluntary memories than did younger adults. Additionally, the life span distribution of involuntary and voluntary memories did not differ in young adults (a clear recency effect) or in older adults (a recency effect and a reminiscence bump). Despite these similarities between involuntary and voluntary memories, there were also important differences in terms of the effects of age on some memory characteristics. Thus, older adults’ voluntary memories were less specific and were recalled more slowly than those of young adults, but there were no reliable age differences in the specificity of involuntary memories. Moreover, older adults rated their involuntary memories as more positive than did young adults, but this positivity effect was not found for voluntary memories. Theoretical implications of these findings for research on autobiographical memory and cognitive aging are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age-related changes in regional cerebral blood flow during working memory for faces

Young and old adults underwent positron emission tomography during the performance of a working memory task for faces (delayed match-to-sample), in which the delay between the sample and choice faces was varied from 1 to 21 s. Reaction time was slower and accuracy lower in the old group, but not markedly so. Values of regional cerebral blood flow (rCBF) were analyzed for sustained activity across delay conditions, as well as for changes as delay increased. Many brain regions showed similar activity during these tasks in both young and old adults, including left anterior prefrontal cortex, which had increased rCBF with delay, and ventral extrastriate cortex, which showed decreased rCBF with delay. However, old adults had less activation overall and less modulation of rCBF across delay in right ventrolateral prefrontal cortex than did the young adults. Old adults also showed greater rCBF activation in left dorsolateral prefrontal cortex across all WM delays and increased rCBF at short delays in left occipitoparietal cortex compared to young adults. Activity in many of these regions was differentially related to performance in that it was associated with decreasing response times in the young group and increasing response times in the older individuals. Thus despite the finding that performance on these memory tasks and associated activity in a number of brain areas are relatively preserved in old adults, differences elsewhere in the brain suggest that different strategies or cognitive processes are used by the elderly to maintain memory representations over short periods of time.     

Recollection- and familiarity-based memory in healthy aging and amnestic mild cognitive impairment.

Little is known about the cognitive mechanisms of the memory impairment associated with amnestic mild cognitive impairment (aMCI). We explored recollection and familiarity in 27 healthy young adults, 45 healthy older adults, and 17 individuals with aMCI. Relative to the younger adults, recollection was reduced in the older adults, especially among those with aMCI. Familiarity did not differ among groups. In the healthy younger and older adults, better performance on a set of clinical memory measures that are sensitive to medial temporal lobe functioning was associated with greater recollection. In addition, among the healthy older adults better executive functioning was also associated with greater recollection. These results are consistent with the notion that recollection is a product of strategic processes mediated by the prefrontal cortex that suppport the retrieval of context-dependent memories from the hippocampus. Hippocampal atrophy associated with aMCI may disrupt this brain network, and thereby interfere with recollection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging increases inattentional blindness to the gorilla in our midst.

When engaged in an attention-demanding task, people are surprisingly vulnerable to inattentional blindness—the failure to notice an unexpected event. Two theories of cognitive aging, attentional capacity models and inhibitory deficit models, make opposite predictions about age differences in susceptibility to inattentional blindness. We tested these predictions using an inattentional blindness paradigm developed by Simons and Chabris (1999) and found that older adults were more likely to experience inattentional blindness than young adults. These results are compatible with attentional capacity models of cognitive aging but not with current inhibitory deficit models. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

On the mechanisms of plasticity in young and older adults after instruction in the method of loci: Evidence for an amplification model.

A meta-analytic review of the literature points out that young adults benefit more from instruction in mnemonic techniques than do older adults. In a study on memory plasticity after instruction in the method of loci, it was found that the cognitive mechanisms of plasticity in young and older adults are largely identical, with the age-related variables of speed of mental operations, associative memory, and number of list rehearsals as the core influences on plasticity. The data fit an amplification model of plasticity, in which variables positively associated with pretest performance and negatively associated with age are positively related to plasticity. Also, older adults were found to comply less with instructions, and when complying, to apply the method of loci correctly less often. Noncompliance, incorrect strategy use, and amplification might explain the adult age differences in treatment gain after instruction in a mnemonic technique. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The resting and activation issue of hypofrontality: a single photon emission computed tomography study in neuroleptic-naive and neuroleptic-free schizophrenic female patients

BACKGROUND: Functional neuroimaging findings of "hypofrontality" in schizophrenic patients is still controversial, due to the heterogeneity of methods and patient samples. This study tries to prevent some of these concerns by studying neuroleptic-naive (NN) and neuroleptic-free (NF) young female patients both in resting conditions and during a frontal cognitive activation task. METHODS: Regional cerebral blood flow (rCBF) was studied at rest and during the Wisconsin Card Sorting Test (WCST) in 25 young acute unmedicated schizophrenic female patients (14 NN and 11 NF) and 15 female controls, using single photon emission computed tomography. RESULTS: The schizophrenic and control groups did not differ in rCBF during the baseline condition, but the schizophrenic group failed to activate the frontal lobe during the WCST condition. In addition, the left anterior temporal rCBF at rest correlated with the Scale for the Assessment of Positive Symptoms total score. CONCLUSIONS: The results suggest that hypofrontality in young acute unmedicated schizophrenic patients is a result of an inability to activate frontal regions during cognition, rather than a baseline decrease in frontal activity. Furthermore, positive symptoms seem to be associated with left temporal cortex activity.     

Synchrony effects in inhibitory control over thought and action.

Two experiments explore whether synchrony between peak circadian arousal periods and time of testing influences inhibitory efficiency for younger and older adults. Experiment 1 assesses inhibitory control over no-longer-relevant thoughts, and Experiment 2 assesses control over unwanted but strong responses, as well as performance on neuropsychological tasks that index frontal function. Inhibitory control is greatest at optimal times for both age groups and is generally greater for younger than for older adults. Performance on 2 neuropsychological measures (Stroop and Trails) also changes over the day, at least for older adults, and is correlated with inhibitory indexes, suggesting that for older adults changes in inhibition may be mediated by circadian variations in frontal functioning. By contrast, access to well-learned responses is not vulnerable to synchrony or age effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of aging and frontal function on the neural correlates of regulative and evaluative aspects of cognitive control.

The influence of aging and frontal function on the neural correlates of regulative and evaluative control was examined by means of event-related brain potentials (ERPs). The behavioral data indicated that interference was greater for older than for younger adults and that this difference was mediated by frontal function. The ERP data revealed effects of aging on the neural correlates of both regulative and evaluative control. Prestimulus neural activity was correlated with response time and frontal function, and these relationships were moderated by the response-to-stimulus interval (RSI); the poststimulus data also revealed age-related differences in the neural correlates of evaluative control that interacted with RSI. These data support predictions derived from the context processing deficit theory of aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unpleasant situations elicit different emotional responses in younger and older adults.

Older adults report less distress in response to interpersonal conflicts than do younger adults, yet few researchers have examined factors that may contribute to these age differences. Emotion regulation is partially determined by the initial cognitive and emotional reactions that events elicit. The authors examined reported thoughts and emotions of younger and older adults (N = 195) while they listened to 3 different audiotaped conversations in which people were ostensibly making disparaging remarks about them. At 4 points during each scenario, the tape paused and participants engaged in a talk-aloud procedure and rated their level of anger and sadness. Findings reveal that older adults reported less anger but equal levels of sadness compared to younger adults, and their comments were judged by coders as less negative. Older adults made fewer appraisals about the people speaking on the tape and expressed less interest in learning more about their motives. Together, findings are consistent with age-related increases in processes that promote disengagement from offending situations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age differences in proactive interference, working memory, and abstract reasoning.

[Correction Notice: An erratum for this article was reported in Vol 23(4) of Psychology and Aging (see record 2008-19072-007). The original article contained an incorrect DOI. The correct DOI is as follows: 10.1037/a0012577.] It has been hypothesized that older adults are especially susceptible to proactive interference (PI) and that this may contribute to age differences in working memory performance. In young adults, individual differences in PI affect both working memory and reasoning ability, but the relations between PI, working memory, and reasoning in older adults have not been examined. In the current study, young, old, and very old adults performed a modified operation span task that induced several cycles of PI buildup and release as well as two tests of abstract reasoning ability. Age differences in working memory scores increased as PI built up, consistent with the hypothesis that older adults are more susceptible to PI, but both young and older adults showed complete release from PI. Young adults' reasoning ability was best predicted by working memory performance under high PI conditions, replicating M. Bunting (2006). In contrast, older adults' reasoning ability was best predicted by their working memory performance under low PI conditions, thereby raising questions regarding the general role of susceptibility to PI in differences in higher cognitive function among older adults. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and everyday judgments: The impact of motivational and processing resource factors.

It has been hypothesized that reductions in cognitive resources might result in older adults engaging in less systematic processing than young adults when making everyday judgments. In 2 experiments, the authors tested individuals aged from 24 to 89 years to examine the degree to which task-related information associated with more superficial versus complex processing differentially influenced performance. They also examined the hypothesis that motivational factors would moderate age differences in processing complexity. In both studies, there were no age differences in the use of simple versus complex processing. Increasing age was, however, associated with increasing selectivity in cognitive resource engagement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The aging decision maker: Cognitive aging and the adaptive selection of decision strategies.

Are older adults' decision abilities fundamentally compromised by age-related cognitive decline? Or can they adaptively select decision strategies? One study (N = 163) investigated the impact of cognitive aging on the ability to select decision strategies as a function of environment structure. Participants made decisions in either an environment that favored the use of information-intensive strategies or one favoring the use of simple, information-frugal strategies. Older adults tended to (a) look up less information and take longer to process it and (b) use simpler, less cognitively demanding strategies. In accordance with the idea that age-related cognitive decline leads to reliance on simpler strategies, measures of fluid intelligence explained age-related differences in information search and strategy selection. Nevertheless, both young and older adults seem to be equally adapted decision makers in that they adjust their information search and strategy selection as a function of environment structure, suggesting that the aging decision maker is an adaptive one. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Brain imaging and age-related changes in cognition

Although there is currently some debate as to the degree of structural changes in the brain that occur with age, there is little doubt that such changes occur. There also are physiological changes in many areas that could have implications for cognitive function in the elderly. One way to study the impact of these age-related changes in the brain on cognition is to use neuroimaging techniques to examine brain activity during the performance of various tasks, and determine how this activity differs between young and older individuals. This approach has been used to study functions such as memory, perception, and attention, and it has generally been found that older individuals utilize different areas of the brain than do young subjects when carrying out the same cognitive task. This has led some researchers to suggest that older persons utilize different functional brain networks, perhaps to compensate for reductions of efficiency in some brain areas. The areas of the brain most often found to be more active during cognitive tasks in the elderly are the frontal lobes. Studies that have directly examined the functional networks utilized during cognition have found that older people do indeed have different functional interactions involving the frontal lobes, and therefore, utilize different functional networks. In some cases this differential activity has been accompanied by cognitive performance in the older participants that is equivalent to that seen in the young, suggesting that greater reliance on this brain region is related in some way to the maintained ability of the older individuals to perform the task. However, data collected to date on this issue are still limited, so although the evidence is intriguing, the definitive interpretation of these findings must await further experiments.     

Age and rate of activation in semantic memory.

Two word-primed picture-naming experiments were carried out to test the hypothesis that rate of activation in semantic memory is slower for older adults than for young adults. The presence of priming effects, both positive and negative, was taken as evidence of activation. In Exp 1 there was no age difference in the time of onset of either facilitation or inhibition by primes. A computer simulation, based on a simple connectionist model, showed that slower processing would have only a minimal effect on the time of onset of priming effects under the assumptions of the model; however, offset of inhibition by primes would be delayed if processing rate were reduced. In Exp 2 older adults showed inhibition by primes over a longer interval than did young adults, which was taken as evidence that the general slowing associated with aging extends to the transmission of activation at the earliest levels of cognitive processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)