Perceptual and cognitive neural correlates of the useful field of view test in older adults

Mechanisms of spatial contextual cueing in younger and older adults

The contextual cueing effect is the phenomenon observed when response time (RT) becomes faster in visual search in repeated context compared with a new one. In the present study, we explored whether the mechanisms involved in the effect are age dependent. We investigated it in younger (N = 20, 12 women, 21.2 ± 1.75 years) and older (N = 19, nine women, 67.05 ± 3.94 years) adults. We found a faster target identification in the repeated configurations with similar magnitude in the two age groups, which indicates that this contextual cueing effect remained intact even in the older participants. To shed light on the underlying mechanisms, we measured and compared the amplitude of three event-related potentials: N2pc, P3, and response-locked LRP. In the younger group, the larger contextual cueing effect (novel-minus-repeated RT difference) correlated positively with a larger difference in amplitude for repeated compared with novel configurations for both the N2pc and the P3 components, but there was no correlation with the response-locked lateralized readiness potential (rLRP) amplitude difference. However, in the older group, only the rLRP amplitude difference between novel and repeated configurations showed an enhancement with larger contextual cueing. These results suggest that different mechanisms are responsible for the contextual effect in the two age groups. It has both an early and an intermediate locus in younger adults: effective attentional allocation and successful stimulus categorization, or decision-making confidence are involved; while in older adults, a late locus was identified: a more efficient response organization led to a faster reaction.

Functional Neural Correlates of a Useful Field of View (UFOV)-Based fMRI Task in Older Adults

Declines in processing speed performance occur in aging and are a critical marker of functional independence in older adults. Studies suggest that Useful Field of View (UFOV) training may ameliorate cognitive decline. Despite its efficacy, little is known about the neural correlates of this task. Within the current study, 233 healthy older adults completed a UFOV-based task while undergoing functional magnetic resonance imaging (fMRI). During the "stimulus" portion of this task, participants must identify a target in the center of the screen and the location of a target in the periphery, among distractors. During the "probe" portion, participants must decide if the object in the center and the location of the target in the periphery were identical to the "stimulus" screen. Widespread bilateral whole-brain activation was observed when activation patterns of the "probe" contrast were subtracted from the "stimulus" contrast. Conversely, the subtraction of "stimulus" from "probe" was associated with discrete activation patterns consisting of 13 clusters. Additionally, when evaluating the variance associated with task accuracy, specific subregions were identified that may be critical for task performance. Our data elucidate the functional neural correlates of a UFOV-based task, a task used in both cognitive training paradigms and assessment of function.

A pilot investigation on the effects of combination transcranial direct current stimulation and speed of processing cognitive remediation therapy on simulated driving behavior in older adults with HIV

Cognitive impairments seen in people living with HIV (PLWH) are associated with difficulties in everyday functioning, specifically driving. This study utilized speed of processing cognitive remediation therapy (SOP-CRT) with transcranial direct current stimulation (tDCS) to gauge the feasibility and impact on simulated driving. Thirty PLWH (M _age = 54.53, SD = 3.33) were randomly assigned to either: sham tDCS SOP-CRT or active tDCS SOP-CRT. Seven indicators of simulated driving performance and safety were obtained. Repeated measures ANOVAs controlling for driver's license status (valid and current license or expired/no license) revealed a large training effect on average driving speed. Participants who received active tDCS SOP-CRT showed a slower average driving speed (p = 0.020, d = 0.972) than those who received sham tDCS SOP-CRT. Non-significant small-to-medium effects were seen for driving violations, collisions, variability in lane positioning, and lane deviations. Combination tDCS SOP-CRT was found to increase indices of cautionary simulated driving behavior. Findings reveal a potential avenue of intervention and rehabilitation for improving driving safety among vulnerable at-risk populations, such as those aging with chronic disease.

Cognitive Training Enhances Auditory Attention Efficiency in Older Adults

Auditory cognitive training (ACT) improves attention in older adults; however, the underlying neurophysiological mechanisms are still unknown. The present study examined the effects of ACT on the P3b event-related potential reflecting attention allocation (amplitude) and speed of processing (latency) during stimulus categorization and the P1-N1-P2 complex reflecting perceptual processing (amplitude and latency). Participants completed an auditory oddball task before and after 10 weeks of ACT (n = 9) or a no contact control period (n = 15). Parietal P3b amplitudes to oddball stimuli decreased at post-test in the trained group as compared to those in the control group, and frontal P3b amplitudes show a similar trend, potentially reflecting more efficient attentional allocation after ACT. No advantages for the ACT group were evident for auditory perceptual processing or speed of processing in this small sample. Our results provide preliminary evidence that ACT may enhance the efficiency of attention allocation, which may account for the positive impact of ACT on the everyday functioning of older adults.