Biology subjects

Gazes, Y.

Publications and source records attributed to Gazes, Y..

4 recordsLinked to original sources

bioRxiv2025

cpCST: A New Continuous Performance Test for High-Precision Assessment of Attention Across the Lifespan

Assessing sustained attention presents methodological challenges, particularly when spanning diverse populations whose baseline sensorimotor functioning may vary significantly. This study introduces the Continuous Performance Critical Stability Task (cpCST), a novel paradigm combining high-density sampling of behavior (30Hz), individualized calibration, and fixed-difficulty assessment to measure attentional control. In a sample of 166 adults (ages 18-76), we evaluated the psychometric properties of the cpCSTs instantaneous reaction time (iRT) metric derived through dynamic time warping. Results demonstrated exceptional reliability (bootstrap split-half r = .999), age invariance, and predictive validity for cognitive performance (flanker and Woodcock-Johnson) and cardiorespiratory fitness (est. VO2max). The cpCST achieved high temporal efficiency, with just two minutes of data correlating at r = .94 with full-task performance, outperforming a standard arrow-based flanker task. The cpCSTs individualized calibration effectively isolated attentional control processes from baseline sensorimotor function, eliminating age-related slowing effects typically observed in reaction time tasks. This approach offers methodological advantages for lifespan studies, clinical populations, integration with neurophysiological measures, and computational modeling approaches while addressing limitations of existing attention assessment paradigms.

animal behavior and cognition↗

bioRxiv2024

Network-based amyloid-beta pathology predicts subsequent cognitive decline in cognitively normal older adults

The deposition of amyloid-{beta} (A{beta}) protein in the human brain is a hallmark of Alzheimers disease and is related to cognitive decline. However, the relationship between early A{beta} deposition and future cognitive impairment remains poorly understood, particularly concerning its spatial distribution and network-level effects. Here, we employed a cross-validated machine learning approach and investigated whether integrating subject-specific brain connectome information with A{beta} burden measures improves predictive validity for subsequent cognitive decline. Baseline regional A{beta} pathology measures from positron emission tomography (PET) imaging predicted prospective cognitive decline. Incorporating structural connectome, but not functional connectome, information into the A{beta} measures improved predictive performance. We further identified a neuropathological signature pattern linked to future cognitive decline, which was validated in an independent cohort. These findings advance our understanding of how A{beta} pathology relates to brain networks and highlight the potential of network-based metrics for A{beta}-PET imaging to identify individuals at higher risk of cognitive decline.

neuroscience↗

bioRxiv2020

fMRI-guided white matter connectivity in fluid and crystallized cognitive abilities in healthy adults

This study examined within-subject differences among three fluid abilities that decline with age: reasoning, episodic memory and processing speed, compared with vocabulary, a crystallized ability that is maintained with age. The data were obtained from the Reference Ability Neural Network (RANN) study from which 221 participants had complete behavioral data for all 12 cognitive tasks, three per ability, along with fMRI and diffusion weighted imaging data. We used fMRI task activation to guide white matter tractography, and generated mean percent signal change in the regions associated with the processing of each ability along with diffusion tensor imaging measures, fractional anisotropy (FA) and mean diffusivity (MD), for each cognitive ability. Qualitatively brain regions associated with vocabulary were more localized and lateralized to the left hemisphere whereas the fluid abilities were associated with brain activations that were more distributed across the brain and bilaterally situated. Using continuous age, we observed smaller correlations between MD and age for white matter tracts connecting brain regions associated with the vocabulary ability than that for the fluid abilities, suggesting that vocabulary white matter tracts were better maintained with age. Furthermore, after multiple comparisons correction, the mean percent signal change for the episodic memory showed positive associations with behavioral performance, and the associations between MD and percent signal change differed by age such that, when divided into three age groups to further explore this interaction, only the oldest age group show a significant negative correlation between the two brain measures. Overall, the vocabulary ability may be better maintained with age due to the more localized brain regions involved, which places smaller reliance on long distance white matter tracts for signal transduction. These results support the hypothesis that functional activation and white matter structures underlying the vocabulary ability contribute to the abilitys greater resistance against aging.

neuroscience↗

bioRxiv2019

White matter regions with low microstructure in young adults are associated with white matter hyperintensities in late life

BackgroundWhite matter hyperintensities (WMH) are areas of increased signal observed on T2-weighted magnetic resonance imaging (MRI) that reflect macrostructural white matter damage frequently observed in aging. The extent to which diminished microstructure precedes or results from white matter damage is unknown. The aim of this study was to evaluate the hypothesis that white matter areas that show normatively lower microstructure are most susceptible to develop WMH. MethodsFive hundred fifty-seven older adults (age: 73.9{+/-}5.7yrs) underwent diffusion weighted imaging (DWI) and T2-weighted magnetic resonance imaging (MRI). Diffusion weighted imaging scans were processed into parametric maps of fractional anisotropy (FA) and T2-weighted MRI scans were segmented into WMH. All images were spatially normalized to standard space. A FA template was created to represent normative values from a separate, independent sample of young, healthy adults (N=49, age: 25.8{+/-}2.8yrs) and a WMH frequency template was created from the segmented WMH in the older adults. We compared FA values between areas defined as WMH with those defined as normal appearing white matter (NAWM) in the older participants. White matter hyperintensity frequency was binned (0-5%, 5-10%, 10-15%, 15-20%, >20%) and we determined whether WMH frequency bins were different by normative FA values defined in the younger group. ResultsFractional anisotropy values were lower (p<0.001) in WMH regions compared with NAWM regions in the older sample. Areas with higher WMH frequency in older adults had lower FA values in younger adults (5-10%>10-15%>15-20%; p<0.001). DiscussionLow FA values are observed in frank WMH, but FA is also normatively low in regions with high WMH frequency prior to damage. Regions with normatively lower microstructure are more susceptible to future damage from factors such as chronic hypoperfusion or pathology.

neuroscience↗