Aging into Perceptual Control: A Dynamic Causal Modeling for fMRI Study of Bistable Perception
Ehsan Dowlati1, Sarah E Adams2, Alexandra B Stiles3
1Virginia Tech Carilion School of Medicine Roanoke, VA, USA.
Frontiers in Human Neuroscience
|April 12, 2016
Summary
Older adults exhibit enhanced top-down control over visual perception, resisting biases more effectively than younger individuals. This age-related difference in neural mechanisms may influence cognitive symptoms in psychopathology.
Area of Science:
- Neuroscience
- Cognitive Aging
- Brain Imaging
Background:
- Aging alters brain activity, often showing a posterior-to-anterior cortical shift.
- The impact of these aging-related neural changes on cognitive symptoms in psychopathology is not well understood.
- Investigating age-related differences in perceptual control offers insights into cognitive resilience.
Purpose of the Study:
- To determine if aging influences the cortical control of perceptual beliefs and biases.
- To examine effective connectivity during volitional control of ambiguous visual stimuli.
- To test for age-related increases in top-down control over early visual networks.
Main Methods:
- Utilized a visual illusion paradigm with a bias training component for ambiguous images.
- Compared functional magnetic resonance imaging (fMRI) data from older (n=16) and younger (n=14) participants.
- Applied Dynamic Causal Models (DCM) to analyze effective connectivity during perceptual decision-making.
Main Results:
- Older adults showed greater resistance to experimenter-induced visual bias compared to younger adults.
- This resistance in older adults correlated with increased activity in prefrontal and temporal cortices.
- Dynamic Causal Models revealed enhanced top-down connectivity from the middle temporal gyrus to the Lingual gyrus in older adults post-training.
Conclusions:
- Older adults demonstrate superior top-down strategic control over perceptual beliefs.
- Age-dependent neural mechanisms, particularly in effective connectivity, influence perceptual bias.
- These findings suggest potential neural pathways relevant to understanding aberrant belief states in psychopathology.
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