ORCID Profile
0000-0003-0275-1476
Current Organisation
University of Adelaide
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Publisher: Informa UK Limited
Date: 13-10-2023
Publisher: Wiley
Date: 03-11-2020
DOI: 10.1111/PSYP.13719
Publisher: Cold Spring Harbor Laboratory
Date: 30-06-2023
DOI: 10.1101/2023.06.28.546988
Abstract: As visual working memory (WM) is limited in capacity, it is important to direct neural resources towards task-relevant information and away from task-irrelevant information. Neural oscillations in the alpha frequency band (8-12 Hz) have been suggested to play a role in the inhibition of distracting information during WM retention in younger adults, but it is unclear if alpha power modulation also supports distractor inhibition in older adults. Here, we recorded electroencephalography (EEG) while 24 younger (aged 18-35) and 24 older (aged 60-86) adults completed a modified delay match-to-s le task in which distractors of varying strength appeared during the retention period. We found: (1) strong distractors impaired WM performance compared with weak and no distractors in both age groups, but there were no age-differences in WM performance (2) while younger adults demonstrated significant increases in alpha power prior to the onset of the distractor in all conditions, decreases in alpha power were seen in all distractor conditions in older adults (3) there was no difference in alpha power between the strong and no distractor conditions and (4) alpha power in anticipation of the distractor was only associated with task performance in younger adults. Our results suggest that younger adults, but not older adults, modulate alpha power in anticipation of distractors during the visual WM retention period.
Publisher: Center for Open Science
Date: 27-04-2021
Abstract: Both selective attention and visual working memory (WM) performance are vulnerable to age related decline. Older adults perform worse on, and are less able to modulate oscillatory power in the alpha frequency range (8-12 Hz) than younger adults in WM tasks involving predictive cues about ‘where’ or ‘when’ a stimulus will be present. However, no study has investigated whether alpha power is modulated by cues predicting ‘how long’ an encoding duration will be. To test this, we recorded electroencephalography (EEG) while 24 younger (aged 18-33 years) and 23 older (aged 60-77 years) adults completed a modified delay match-to-s le task where participants were cued to the duration (either 0.1 s or 0.5 s) of an encoding stimulus consisting of 4 coloured squares. We found: (1) predictive cues increased WM capacity, but long encoding duration trials led to reduced WM capacity in both age groups, compared to short encoding duration trials (2) no evidence for differences in preparatory alpha power between predictive and neutral cues for either short or long encoding durations, but preparatory alpha suppression was weaker in older adults (3) retention period oscillatory power differed between short and long encoding duration trials, but these differences were no longer present when comparing the trial types from the onset of the encoding stimulus and (4) oscillatory power in the preparatory and retention periods were not related to task performance. Our results suggest that preparatory alpha power is not modulated by predictive cues towards encoding duration during visual WM, however, reductions in alpha/beta oscillatory power during visual WM retention may be linked to the encoding stimulus, rather than a process specific to WM retention.
Publisher: Cold Spring Harbor Laboratory
Date: 20-11-2019
DOI: 10.1101/848127
Abstract: Working memory (WM) is vulnerable to age-related decline, particularly under high loads. Visual alpha oscillations contribute to WM performance in younger adults, and although alpha decreases in power and frequency with age, it is unclear if alpha activity supports WM in older adults. We recorded electroencephalography (EEG) while 24 younger (aged 18-35 years) and 30 older (aged 50-86) adults performed a modified Sternberg task with varying load conditions. Older adults demonstrated slower reaction times at all loads, but there were no significant age differences in accuracy. Regardless of age, alpha power decreased, and alpha frequency increased with load during encoding, and the magnitude of alpha suppression during retention was larger at higher loads. While alpha power during retention was lower than fixation in older, but not younger adults, the relative change from fixation was not significantly different between age groups. In idual differences in alpha power did not predict performance for either age groups or at any WM loads. Future research should elaborate the functional significance of alpha power and frequency changes that accompany WM performance in cognitive ageing.
Publisher: Springer Science and Business Media LLC
Date: 20-11-2020
Publisher: Cold Spring Harbor Laboratory
Date: 17-07-2020
DOI: 10.1101/2020.07.16.207738
Abstract: As working memory (WM) is limited in capacity, it is important to direct neural resources towards processing task-relevant information while ignoring distractors. Neural oscillations in the alpha frequency band (8-12 Hz) have been suggested to play a role in the inhibition of task-irrelevant information during WM, although results are mixed, possibly due to differences in the type of WM task employed. Here, we examined the role of alpha power in inhibition of anticipated distractors of varying strength using a modified Sternberg task where the encoding and retention periods were temporally separated. We recorded EEG while 20 young adults completed the task and found: 1) slower reaction times in strong distractor trials compared to weak distractor trials 2) increased alpha power in posterior regions from baseline prior to presentation of a distractor regardless of condition and 3) no differences in alpha power between strong and weak distractor conditions. Our results suggest that parieto-occipital alpha power is increased prior to a distractor. However we could not find evidence that alpha power is further modulated by distractor strength.
Publisher: Center for Open Science
Date: 14-02-2022
Abstract: Visual working memory (WM) is vulnerable to age-related decline, but the causes of such performance deficits are unclear. Here, we investigated whether the ability to consolidate items into the visual WM store differs between young and older adults. 18 older (aged 60-77) and 17 younger adults (aged 18-35) completed a change detection paradigm that measured visual WM consolidation rate. A memory set of either 2, 4 or 6 coloured squares was presented, followed by a pattern mask to disrupt WM consolidation. The consolidation time between memory set and mask varied between 17 and 484 ms. We found that older adults demonstrated poorer performance (measured by d’) across all loads and were particularly affected by shorter consolidation times at load-2 compared with younger adults. However, both young and older adults were equally affected by the masks at load-4 and load-6. We demonstrate evidence for altered WM consolidation in older adults, which may explain poorer visual WM performance with age.
Publisher: Cold Spring Harbor Laboratory
Date: 09-2021
DOI: 10.1101/2021.08.31.458328
Abstract: Previous research using electroencephalography (EEG) and magnetoencephalography (MEG) has shown that neural oscillatory activity within the alpha band (8-12 Hz) becomes slower and lower in litude with advanced age. However, most studies have focused on quantifying age-related differences in periodic oscillatory activity with little consideration of the influence of aperiodic activity on these measures. The aim of this study was to investigate age differences in aperiodic activity inherent in the resting EEG signal. We assessed aperiodic activity in 85 healthy younger adults (mean age: 22.2 years, SD: 3.9, age range: 18–35, 37 male) and 92 healthy older adults (mean age: 66.1 years, SD: 8.2, age range 50–86, 53 male) by fitting the 1/f-like background activity evident in EEG power spectra using the fitting oscillations & one over f (FOOOF) toolbox. Across the scalp, the aperiodic exponent and offset were smaller in older compared to younger participants, reflecting a flatter 1/f-like slope and a downward broadband shift in the power spectra with age. Before correcting for aperiodic activity, older adults showed slower peak alpha frequency and reduced peak alpha power relative to younger adults. After correcting for aperiodic activity, peak alpha frequency remained slower in older adults however, peak alpha power no longer differed statistically between age groups. The large s le size utilized in this study, as well as the depth of analysis, provides further evidence that the aperiodic component of the resting EEG signal is altered with aging and should be considered when investigating neural oscillatory activity.
No related grants have been discovered for Sabrina Sghirripa.