Functional response in ventral temporal cortex differentiates mild cognitive impairment from normal aging.

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Neurology

Background:

• Mild cognitive impairment (MCI) is a transitional stage between normal aging and dementia.
• Identifying early biomarkers for MCI is crucial for timely intervention.
• Neocortical atrophy and task impairment are later signs of cognitive decline.

Purpose of the Study:

• To identify altered brain activation patterns in amnestic MCI that may precede cognitive deficits.
• To investigate functional magnetic resonance imaging (fMRI) differences between MCI and normal seniors (NS).
• To determine if specific brain activation patterns can accurately discriminate between MCI and NS.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to measure brain activity during a lexical decision (LD) task.
• Participants included individuals with amnestic MCI and normal seniors (NS).
• Voxel-based morphometry was employed to assess for neocortical atrophy.

Main Results:

• Both MCI and NS groups performed the LD task with high accuracy (>89%).
• MCI group showed reduced fMRI activation in occipitotemporal regions and inferior frontal cortex compared to NS.
• MCI group exhibited increased activation in bilateral anterior cingulate cortex.
• Reduced fMRI response in the left and right midfusiform gyri accurately discriminated MCI from NS (AUC = 0.93).

Conclusions:

• Disrupted functional response in the ventral temporal lobe, specifically reduced activation in the midfusiform gyri, accurately distinguishes individuals with MCI from NS.
• These findings suggest that fMRI-based detection of altered brain function can serve as an early indicator of cognitive decline.
• This approach may have implications for identifying seniors at risk for developing dementia.