Age-related Changes In Processing Research Articles

Age-related changes in the organization of spontaneously occurring behaviors

Age-related changes in spatial and temporal processing have been documented across a range of species. Rodent studies typically investigate differences in performance between adult and senescent animals; however, progressive loss of neurons in the hippocampus and cortex has been observed to occur as early as after adolescence. Therefore, the current study evaluated the effects of age in three- and ten-month-old female rats on the organization of movement in open field and food protection behaviors, two tasks that have previously dissociated hippocampal and cortical pathology. Age-related differences were observed in general measures of locomotion, spatial orientation, and attentional processing. The results of the current study are consistent with age-related changes in the processing of spatial information and motivation that occur earlier in life than previously anticipated. These observations establish a foundation for future studies evaluating interventions that influence these age-related differences in performance.

Auditory P300 in Noise in Younger and Older Adults.

Older adults often report difficulty hearing in background noise which is not completely attributable to peripheral hearing loss. Although age-related declines in cognition and hearing in background noise occur, the underlying age-related changes in processing of auditory stimuli in background noise has yet to be fully understood. The auditory P300 has the potential to elucidate the effects of age on auditory and cognitive processing of stimuli in background noise, but additional research is warranted. The purpose of this study was to investigate age-related differences in cognitive processing of auditory stimuli by evoking the auditory P300 at multiple signal-to-noise ratios (SNRs). A two-group, repeated measures study design was used. A convenience sample of 35 participants, 15 older adults (mean age of 66.4 yr) and 20 younger adults (mean age of 21.1 yr), participated in the study. All participants had negative otologic and neurological histories. The auditory P300 was evoked using an oddball paradigm with 500 (frequent) and 1000 Hz (target) tonal stimuli in quiet and in the presence of background noise at +20, +10, and 0 SNRs. P300 amplitudes and latencies were measured in each condition for every participant. Repeated measures analyses of variance were conducted for the amplitude and latency measures of the P300 for each group. Results from this study demonstrated P300 latencies were significantly longer in older adults in noise at the most challenging condition (0 SNR) compared with the quiet condition and between the +10 SNR and 0 SNR conditions. Although older adults had significantly longer P300 latencies compared with younger adults, no significant group by listening condition interaction existed. No significant P300 amplitude differences were found for group, noise, or group × listening condition interactions. Results provide evidence that auditory cortical processing, regardless of age, is poorer at more difficult SNRs. However, results also demonstrate that older adults perform significantly poorer than younger adults. This supports the notion that some degree of age-related decline in synchronous firing and rate of transmission of the auditory cortical neurons contributing to the auditory P300 exists. Studies are needed to further understand the impact of noise on auditory cortical processing across populations.

Age-related changes in processing faces from detection to identification: ERP evidence

We examined the ability of people 70 to 90 years old to apply global, configural, and featural face-processing strategies. In addition we investigated age-related changes in the ability to categorize faces at basic, subordinate, and individual levels. Using the N170 potential as index of early face processing and the P300 component as index of categorical decision making and effort, we found significant age-related perceptual changes which slowed and somewhat impaired face processing. Specifically, older participants had problems integrating face features into global structures, demonstrating enhanced dependence on distal global information. They did not apply configural computations by default while processing faces which suggests that, unless identification is required, they process faces only at a basic level. These perceptual changes could be the cause for slower and less accurate subordinate categorization, particularly when it is based on details. At the neural levels face processing was not right-lateralized, reflecting excessive involvement of the left hemisphere in perception leading to a more general reduction of interhemispheric asymmetry. In addition we found excessive but nonselective activation of frontal regions adding support to the view that executive control and particularly inhibition of irrelevant input are reduced in the elderly.

Age-related changes in early novelty processing as measured by ERPs

This study investigated age-related changes in the early processing of novel visual stimuli using ERPs. Well-matched old ( n = 30), middle-aged ( n = 30), and young ( n = 32) subjects were presented standard, target/rare, and perceptually novel visual stimuli under Attend and Ignore conditions. Our results suggest that the anterior P2 component indexes the motivational salience of a stimulus as determined by either task relevance or novelty. Its enhancement by focused attention does not decrease with age. Its responsiveness to novel stimuli is particularly striking in older adults. The age-related increase in the anterior P2 to novel visual stimuli does not appear to be due to impaired inhibitory control associated with aging. Rather, the enhanced anterior P2 to novel stimuli in older adults may be linked to age-related changes in the process of matching unusual visual stimuli to stored representations, which is indexed by the temporally overlapping anterior N2 component whose amplitude substantially decreases with age.

Ｎ‐ｂａｃｋ課題を用いた視覚的ワーキングメモリの保持と処理の加齢変化

Age-related changes in processing and retention in visual working memory were examined using visual stimuli that do not allow for verbal-name coding. Participants ranged in age from their 20s to 70s, and data was analyzed using the cross-sectional cohort method. The N-back task was used, and results from the 0-back task (recognition of the last of the continuously presented stimuli) and the 1-back task (recognition of the penultimate stimulus) were compared. The results showed a sudden decrease in performance on the 0-back task for participants in their 60s, and a relatively linear decrease on the 1-back task from the 30s. These results suggest that aging-related changes in visual working memory reflect a decrease in processing speed. They also suggests that the functions of "simple retention" and "processive retention" are different.

Age-related differences in medial prefrontal activation in response to emotional images

Research has suggested that aging results in a "positivity effect," with young adults dwelling on negative information, and older adults attending to positive information. In order to understand age-related changes in emotional processing underlying this effect, the present fMRI study compared neural activity in young and older adults as they viewed positive, negative, and neutral images. Results indicated a striking age-related reversal in the valence of information eliciting activity within the ventromedial prefrontal cortex (VMPFC). Negative in comparison with positive images activated the VMPFC more for young adults, whereas positive in comparison with negative images activated the VMPFC more for the older adults. The VMPFC is a region associated with the processing of emotional information, and more specifically, with emotion generation and emotion regulation. Therefore, the present results suggest that age-related changes in these processes implemented by the VMPFC contribute to older adults' "positivity effect."