The aging frontal lobe in health and disease : a structural magnetic resonance imaging study

Cortical and subcortical regions of the brain decrease in volume in normal as well as pathological aging. Previous studies indicate that certain parts of the brain, like the prefrontal cortex, may be particularly vulnerable to age-related processes which are manifested by significant volume loss in this region. Cortical volume loss may be further enhanced by different kinds of pathology in the brain.

The purpose of this study was to further investigate regional volumetric changes of the frontal lobe in normal aging and in aging patients with dementia.

In study I-III patients with frontotemporal lobar degeneration (FTLD), Alzheimer’s disease (AD) and healthy controls are investigated. Cortical atrophy is related to clinical symptoms (study I), discussed in relation to gross morphology and cytoarchitecture (study II), and compared with the atrophy in the hippocampus (study III).

In study IV a large number of normal elderly participants are investigated. Age-related volume loss in the limbic system (the dorsal anterior cingulate cortex and the hippocampus) is compared with atrophy of a region of the prefrontal cortex (the orbitofrontal cortex). Volumetric data of frontal and temporal cortical regions and the hippocampus was acquired by manual delineation on structural magnetic resonance images.

Results of study I and III reveal that the clinical symptoms displayed by the subtypes of FTLD are commonly reflected in a specific pattern of atrophy in frontotemporal cortices as well as in the hippocampus. Study II suggests that the surface morphology of sulci and gyri may be unreliable landmarks for cyto-architectonic regions of the frontal cortex. Study IV finally indicates that a common characteristic of limbic regions may be that age-related volume loss is delayed in comparison to regions of the prefrontal cortex. Results also suggest that the dorsal anterior cingulate is more resistant to age-related volume loss than hippocampus, which implies that age-related volume loss occurs at different rates for different regions also within the limbic system.

List of scientific papers

I. Cortical Morphometric Subclassification of Frontotemporal Lobar Degeneration. Olof Lindberg, Per Östberg, Bram Zandbelt, Johanna Öberg, Yi Zhang, Lisa Botes, Christian Andersen, Nenad Bogdanović, Lars-Olof Wahlund. AJNR Am J Neuroradiol. 2009;30:1233–39.
https://doi.org/10.3174/ajnr.A1545

II. A Comparison Between Volumetric Data Generated by Voxel-Based Morphometry and Manual Parcellation of Multimodal Regions of the Frontal Lobe. Olof Lindberg, Amir Manzouri, Eric Westman, Lars-Olof Wahlund. [Accepted]
https://doi.org/10.3174/ajnr.A3093

III. Hippocampal Shape Analysis in Alzheimer’s Disease and Frontotemporal Lobar Degeneration Subtypes. Olof Lindberg, Mark Walterfang, Jeffrey C.L. Looi, Nikolai Malykhin, Per Östberg, Bram Zandbelt , Martin Styner, Beatriz Paniagua, Dennis Velakoulis, Eva Örndahl, Lars-Olof Wahlund. [Accepted]
https://doi.org/10.3233/JAD-2012-112210

IV. Selective preservation of the grey matter in the dorsal part of the anterior cingulate cortex at old and very old age. Olof Lindberg, Carl-Henrik Ehrenkrona, Linnea Engström, Yi Zhang, Eva Örndahl, Erika Jonsson Laukka, Grégoria Kalpouzos, Lars-Olof Wahlund. [Manuscript]