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Functional compensation in incipient Alzheimer's disease
A Caroli1, C Geroldi, F Nobili
1LENITEM Laboratory of Epidemiology, Neuroimaging, and Telemedicine, IRCCS San Giovanni di Dio-FBF, 25125 Brescia, Italy.
Neurobiology of Aging
|June 17, 2008
Summary
Early Alzheimer's disease (AD) shows brain compensation mechanisms. The brain attempts to counteract neuronal loss with preserved perfusion in certain areas, despite atrophy and hypoperfusion in others.
Area of Science:
- Neuroscience
- Radiology
- Gerontology
Background:
- Alzheimer's disease (AD) is a progressive neurodegenerative disorder.
- Incipient AD is characterized by early pathological changes and potential compensatory mechanisms.
- Understanding these mechanisms is crucial for early diagnosis and intervention.
Purpose of the Study:
- To investigate functional compensation mechanisms in incipient Alzheimer's disease (AD).
- To identify brain regions with compensatory perfusion or functional depression in early AD.
Main Methods:
- Utilized Magnetic Resonance (MR) imaging and 99mTc ECD SPECT scans.
- Analyzed brain images using SPM2 software to generate t maps.
- Assessed whole-brain gray matter (GM) atrophy and functional changes, masking them to evaluate perfusion.
Main Results:
- Incipient AD exhibited GM atrophy and hypoperfusion in medial temporal and temporoparietal lobes.
- Compensatory preserved perfusion was observed in the posterior cingulate, hippocampus, amygdala, and insula.
- Functional depression occurred in bilateral parahippocampal gyri, indicating regional differences in brain response.
Conclusions:
- A perfusional compensatory mechanism occurs in the neocortex in AD.
- Perfusional depression is evident in the medial temporal lobe during early AD.
- These findings illuminate the brain's reactive strategies against AD-related pathological changes.
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