Thad A. Polk

Modulation of neural variability: Age-related reduction, GABAergic basis, and behavioral implications

This study investigates how aging and GABA levels modulate neural variability during visual processing and links it to visual discrimination performance.

Age-related differences in GABA: Impact of analysis technique

This study examines how different analysis techniques affect age-related differences in GABA concentrations, finding that tissue composition significantly influences results.

Age-related declines in neural distinctiveness correlate across brain areas and result from both decreased reliability and increased confusability

This study finds age-related declines in neural distinctiveness across multiple brain regions, driven by reduced reliability and increased confusability of neural activity patterns.

GABA levels in ventral visual cortex decline with age and are associated with neural distinctiveness

This study finds that GABA levels decrease with age in the ventral visual cortex and are linked to reduced neural distinctiveness in older adults.

Age-related differences in white matter: Understanding tensor-based results using fixel-based analysis

This study uses fixel-based analysis to examine age-related white matter differences in older and younger adults, revealing specific microstructural changes associated with aging.

Neural Correlates of Working Memory Training: Evidence for Plasticity in Older Adults

This study shows that working memory training increases neural efficiency and shifts activation peaks towards higher loads in older adults, indicating functional plasticity.

Higher performers upregulate brain signal variability in response to more feature-rich visual input

The paper finds that higher cognitive performers show greater brain signal variability in response to more complex visual stimuli, suggesting a link between neural variability and cognitive performance.

Effects of Aging on the Encoding of Spatial Direction in the Human Brain

This study investigates age-related changes in neural tuning for spatial direction using fMRI, finding broader tuning in older adults in the primary visual cortex but no behavioral impact.

Neural distinctiveness declines with age in auditory cortex and is associated with auditory GABA levels.

This study shows that older adults show less distinct neural activation patterns in auditory cortex and lower GABA levels, with GABA levels predicting neural distinctiveness in older adults.

Michigan Neural Distinctiveness (MiND) project: Investigating the scope, causes, and consequences of age-related neural dedifferentiation

The MiND project investigates age-related neural dedifferentiation by examining its scope, causes, and behavioral consequences using multimodal imaging and behavioral measures.