Increased Cortical Thickness in Alzheimer's Disease

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Alzheimer's disease (AD) is characterized by widespread brain atrophy.
• Some brain regions, including the anterior cingulate cortex (ACC), may show increased thickness in AD patients compared to controls.
• The clinical significance and underlying mechanisms of this increased cortical thickness are not well understood.

Purpose of the Study:

• To investigate the occurrence and clinical relevance of increased cortical thickness in sporadic Alzheimer's disease (AD).
• To determine if increased cortical thickness in AD is associated with specific clinical symptoms.
• To explore the relationship between regions of increased cortical thickness and areas of brain atrophy.

Main Methods:

• Analysis of cross-sectional clinical, neuropsychological, and neuroimaging data from the Alzheimer's Disease Neuroimaging Initiative (ADNI).
• Comparison of cortical thickness between AD subjects and healthy controls.
• Application of atrophy network mapping to identify functional connections between increased thickness and atrophy regions.

Main Results:

• AD patients exhibited increased cortical thickness in the anterior cingulate cortex (ACC) and visual cortex.
• Increased thickness in the left ACC correlated with preserved cognitive function.
• Increased thickness in the left visual cortex was associated with the occurrence of hallucinations.
• Regions with increased thickness were functionally connected to, yet anticorrelated with, regions of brain atrophy (r = -0.81, p < 0.05).

Conclusions:

• Increased cortical thickness in AD is clinically relevant and associated with symptoms.
• This phenomenon preferentially occurs in brain regions functionally linked to, but anticorrelated with, areas of atrophy.
• Findings suggest potential compensatory neuroplasticity mechanisms in response to neurodegeneration in Alzheimer's disease.