Print Close

Regional Heterogeneity of Aging Gradients Informed by Cyto- and Myelo-architectonic Organization

Poster No:

928

Submission Type:

Abstract Submission

Authors:

Kristen Kennedy¹, David Hoagey², Ekarin Pongpipat¹, Karen Rodrigue¹

Institutions:

¹The University of Texas at Dallas, Dallas, TX, ²Washington University in St. Louis, St. Louis, MO

First Author:

Kristen Kennedy, PhD
The University of Texas at Dallas
Dallas, TX

Co-Author(s):

David Hoagey, PhD
Washington University in St. Louis
St. Louis, MO

Ekarin Pongpipat
The University of Texas at Dallas
Dallas, TX

Karen Rodrigue, PhD
The University of Texas at Dallas
Dallas, TX

Introduction:

Differences in cell density across the cerebral cortex has been linked to the size and caliber of dendrites, axons, and intra-laminar white matter. Aging of the human brain is characterized by high heterogeneity and heterochronicity, but this differential aging pattern is not well-understood. Utilizing a cyto- and myelo-archetectonic informed approach to brain parcellation allows for an examination of the pattern of brain aging, based on regional underlying cellular properties. The current study utilizes the digitized von Economo-Koskinas (vE-K) atlas to investigate whether the variance in brain aging follows these structural organization properties. The vE-K parcellation scheme delineates brain regions by their cellular complexity with five cortical types (ordered from rich complexity to poor complexity): agranular, frontal, parietal, polar, and granular.

Methods:

Participants included 97 healthy adults across the lifespan (aged 24-90 years old, mean age 58, 59 women) from the Dallas Area Longitudinal Lifespan Aging Study (DALLAS) who underwent an MRI session that included multi shell diffusion imaging and a T1-w scan. Biophysical modeling using NODDI was conducted to compute neurite density, orientation dispersion, and extracellular free-water from each of the vE-K parcels. The t1-w image was used to map the parcels into diffusion space for each participant. Multi-level modeling was used to first determine the association between each NODDI metric and the associated cortical type (CT), and then to estimate how that relationship differs across the lifespan.

Results:

The results indicated that neurite density was the lowest in frontal and parietal cortical types, and displayed the flattest age-related slope. There was no significant difference in neurite density between the granular and agranular cortices. Orientation dispersion was generally high in association cortices, particular in the parietal cortical type, and lowest in agranular cortices. There were strong age differences in orientation dispersion across the cortical types. For extracellular free water index, frontal and parietal association-like cortices demonstrated consistently high free water values and very steep age slopes across all cortical types, but especially for granular areas.

.

Conclusions:

Based on these findings we conclude that incorporating cellular-organization histological information, such as that available in the digitized von Economo-Koskinas atlas, adds important information to structural neuroimaging given its still coarse resolution. Cellular complexity, at the laminar level, is associated with gray matter diffusion properties and does so at a regionally differential fashion. We found that areas with low myelin content have the lowest neurite density and consistently high levels of orientation dispersion and free water.The presence of granule cells with a lower density allows for increased complexity of the laminar structure and the ability to propagate larger dendritic arbors and maximize short range connections. We demonstrate that the prototypical association cortex types, frontal and parietal, which contain some granule cells, but with lower density, are the most vulnerable to the aging process. We also provide evidence for a retrogenesis-like gradient of brain aging, where primary motor, sensory, auditory, and visual areas develop earliest and remain intact longer than the later developing association cortices and also underscores developmental and evolutionary precedence in brain aging.

Lifespan Development:

Aging ¹

Modeling and Analysis Methods:

Diffusion MRI Modeling and Analysis

Segmentation and Parcellation

Neuroanatomy, Physiology, Metabolism and Neurotransmission:

Cortical Anatomy and Brain Mapping

Cortical Cyto- and Myeloarchitecture ²

Keywords:

Aging

Cortex

Cortical Layers

MRI

NORMAL HUMAN

Segmentation

STRUCTURAL MRI

^1|2Indicates the priority used for review

Abstract Information

By submitting your proposal, you grant permission for the Organization for Human Brain Mapping (OHBM) to distribute your work in any format, including video, audio print and electronic text through OHBM OnDemand, social media channels, the OHBM website, or other electronic publications and media.

I accept

The Open Science Special Interest Group (OSSIG) is introducing a reproducibility challenge for OHBM 2025. This new initiative aims to enhance the reproducibility of scientific results and foster collaborations between labs. Teams will consist of a “source” party and a “reproducing” party, and will be evaluated on the success of their replication, the openness of the source work, and additional deliverables. Click here for more information. Propose your OHBM abstract(s) as source work for future OHBM meetings by selecting one of the following options:

I do not want to participate in the reproducibility challenge.

Please indicate below if your study was a "resting state" or "task-activation” study.

Other

Healthy subjects only or patients (note that patient studies may also involve healthy subjects):

Healthy subjects

Was this research conducted in the United States?

Yes

Are you Internal Review Board (IRB) certified? Please note: Failure to have IRB, if applicable will lead to automatic rejection of abstract.

Yes, I have IRB or AUCC approval

Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.

Yes

Were any animal research approved by the relevant IACUC or other animal research panel? NOTE: Any animal studies without IACUC approval will be automatically rejected.

Not applicable

Please indicate which methods were used in your research:

Structural MRI

Diffusion MRI

For human MRI, what field strength scanner do you use?

3.0T

Which processing packages did you use for your study?

Free Surfer

Provide references using APA citation style.

N/A

UNESCO Institute of Statistics and World Bank Waiver Form

I attest that I currently live, work, or study in a country on the UNESCO Institute of Statistics and World Bank List of Low and Middle Income Countries list provided.