Search

Blink-related oscillations (BROs) are newly discovered neurophysiological brainwave responses associated with spontaneous blinking, and represent environmental monitoring and awareness processes as the brain evaluates new visual information appearing after eye re-opening. BRO responses have been demonstrated in healthy young adults across multiple task states and are modulated by both task and environmental factors, but little is known about this phenomenon in aging. To address this, we undertook the first large-scale evaluation of BRO responses in healthy aging using the Cambridge Centre for Aging and Neuroscience (Cam-CAN) repository, which contains magnetoencephalography (MEG) data from a large sample (N = 457) of healthy adults across a broad age range (18–88) during the performance of a simple target detection task. The results showed that BRO responses were present in all age groups, and the associated effects exhibited significant age-related modulations comprising an increase in sensor-level global field power (GFP) and source-level theta and alpha spectral power within the bilateral precuneus. Additionally, the extent of cortical activations also showed an inverted-U relationship with age, consistent with neurocompensation with aging. Crucially, these age-related differences were not observed in the behavioral measures of task performance such as reaction time and accuracy, suggesting that blink-related neural responses during the target detection task are more sensitive in capturing aging-related brain function changes compared to behavioral measures alone. Together, these results suggest that BRO responses are not only present throughout the adult lifespan, but the effects can also capture brain function changes in healthy aging—thus providing a simple yet powerful avenue for evaluating brain health in aging. [ABSTRACT FROM AUTHOR]

Performance in perceptual tasks often improves with practice. This effect is known as "perceptual learning," and it has been the source of a great deal of interest and debate over the course of the last century. Here, we consider the effects of perceptual learning within the context of signal detection theory. According to signal detection theory, the improvements that take place with perceptual learning can be due to increases in "internal signal strength" or decreases in "internal noise." We used a combination of psychophysical techniques (external noise masking and double-pass response consistency) that involve corrupting stimuli with externally added noise to discriminate between the effects of changes in signal and noise as observers learned to identify sets of unfamiliar visual patterns. Although practice reduced thresholds by as much as a factor of 14, internal noise remained virtually fixed throughout training, indicating learning served to predominantly increase the strength of the internal signal. We further examined the specific nature of the changes that took place in signal strength by correlating the externally added noise with observer's decisions across trials (response classification). This technique allowed us to visualize some of the changes that took place in the linear templates used by the observers as learning occurred, as well as test the predictions of a linear template-matching model. Taken together, the results of our experiments offer important new theoretical constraints on models of perceptual learning.

Objectives: Loneliness is a modifiable risk factor for depression and dementia in older age. Validated interventions are needed to mitigate the impact of loneliness in older adults. Some evidence suggests that mindfulness meditation may reduce stress, improve mood and cognitive function, and may also impact loneliness per se. Many meditation apps offer an accessible way to meditate at home. However, robust research is needed to assess the benefits of meditation using this technology for older adults. Muse is a meditation app that analyzes brain signals during meditation and provides users with real-time neurofeedback on their level offocus. Methods: We conducted a pilot, randomized controlled trial to establish the acceptability and feasibility of a remote, mindfulness intervention using Muse in older adults, and to obtain preliminary data on its impact on mood and cognition. Twenty-six adults reporting feeling lonely were enrolled and randomized to an 8-week Muse- based meditation (MM) or a brain- training active control (BT) program. The MM group completed meditation sessions with real- time neurofeedback and guided meditation sessions using Muse. The BT group completed cognitively challenging games on the commercially available Peak app and listened to podcasts. The groups were matched on the amount of interactions with study staff and total program duration. Outcome measures included standardized self-report scales of loneliness, stress, depression, well-being, quality of life, sleep disturbance, resilience, and mindfulness. Staff blinded to program assignment administered cognitive tasks of episodic memory, working memory, and sustained attention, as well as a breath counting task. Assessments were taken at Pre, Mid, and Post intervention, and after a 2-month and 4-month (4M) follow-upperiod. Results: Participants found both programs engaging and the remote assessments were feasible. The MM group showed a greater improvement in depressive symptoms, and psychological andphysical QOL, compared to the BT group, at Post and at 4M. Conclusions: A Muse-based mindfulness program is an acceptable and accessible intervention for older adults. A large-scale randomized trial is warranted to evaluate the efficacy of this intervention in this group. [ABSTRACT FROM AUTHOR]

The completion of partly occluded objects appears instantaneous and effortless, but empirically takes measurable time. The current study investigates how amount of occlusion affects the time course and mechanisms of visual completion. Experiment 1 used a primed-matching paradigm to determine completion times for objects occluded by various amounts. Experiments 2 and 3 used a dot-localization paradigm to probe completed contour representations for a qualitative shift above some spatial limit. The results demonstrate that time to completion rises with amount of occlusion. Nonetheless, the visual system can complete highly occluded objects, even when the occlusion renders visible contours nonrelatable. Furthermore, prolonged completion times for highly occluded objects do not result from a breakdown of low-level interpolation processes: The same contour completion mechanism operates on objects occluded by different spatial extents.