Age-related changes to oscillatory dynamics in hippocampal and neocortical networks

Abstract

Recent models of hippocampal function have emphasized its role in relational binding - the ability to form lasting representations regarding the relations among distinct elements or items which can support memory performance, even over brief delays (e.g., several seconds). The present study examined the extent to which aging is associated with changes in the recruitment of oscillatory activity within hippocampal and neocortical regions to support relational binding performance on a short delay visuospatial memory task. Structural magnetic resonance imaging and MEG were used to characterize potential age-related changes in hippocampal volume, oscillatory activity, and subsequent memory performance, and the relationships among them. Participants were required to bind the relative visuospatial positions of objects that were presented singly across time. Subsequently, the objects were re-presented simultaneously, and participants were required to indicate whether the relative spatial positions among the objects had been maintained. Older and younger adults demonstrated similar task accuracy, and older adults had preserved hippocampal volumes relative to younger adults. Age-group differences were found in pre-stimulus theta (∼5Hz) and beta (∼20Hz) oscillations, and this pre-stimulus activity was related to hippocampal volumes in younger adults. Age-group differences were also found in the recruitment of oscillatory activity from the pre-stimulus period to the task. Only younger adults showed a task-related change in theta power that was predictive of memory performance. In contrast, older adults demonstrated task-related alpha (∼10Hz) oscillatory power changes that were not observed in younger adults. These findings provide novel evidence for the role of the hippocampus and functionally connected regions in relational binding that is disrupted in aging. The present findings are discussed in the context of current models regarding the cognitive neuroscience of aging.

Age-related changes in neural oscillations supporting context memory retrieval

“…In older adults, we did not find a significant relationship between theta and context memory performance. A similar lack of relationship between theta and associative memory accuracy in a short-term memory task has been previously shown for older adults (Rondina et al, 2015). Instead, we found a longer lasting theta synchronization effect over left parietal electrodes for the old, compared to the young, which remained significant after controlling for age differences in context memory.…”

“…Some EEG evidence from a visuospatial associative encoding task suggests that age-related reductions in theta synchronization following event onset may contribute to older adults’ memory impairments (Crespo-Garcia, Cantero, & Atienza, 2012). Similarly, magnetoencephalography (MEG) evidence suggests that increased stimulus-related theta power during encoding predicts relational binding success for the young but not the old in a short-term memory task (Rondina et al, 2015). By contrast, alpha and beta desynchronization was greater for the old than the young but did not support memory performance.…”

Transcranial Low-Level Laser (Light) Therapy for Brain Injury

“…60 The pulsed light may have resonance with existing brain waves such as theta waves that oscillate at 4-10 Hz, found in the hippocampus (or a similar region). 62 …”

Consistent pre-stimulus influences on auditory perception across the lifespan

“…One possibly is that the present sample size was not sufficient to reveal systematic shifts in the relevant frequencies or that such effects are smaller than the frequency resolution employed here. On the other hand it could also be that the mechanisms and time scales by which pre-stimulus activity shapes sensory encoding remain indeed the same, despite an overall change in the relative amplitude of different frequency bands (Babiloni et al, 2006;Cummins and Finnigan, 2007;Rondina et al, 2016;Vlahou et al, 2014). Support for the latter conclusion comes also from studies demonstrating a similar modulation of alpha band activity by acoustical structure and task demands in young and elderly participants (Erb and Obleser, 2013;Tune et al, 2018;Wostmann et al, 2015), from the comparable alignment of lateralized alpha modulations to acoustic stimuli across age groups (Tune et al, 2018), and from a study demonstrating a similar modulation of behavioural performance by stimulus-entrained delta-band activity in young and older participants (Henry et al, 2017).…”