Mapped four new brain areas involved in many cognitive processes

Summary: Researchers have mapped four new areas of the human anterior prefrontal cortex that play a critical role in cognitive processing. Two of these newly mapped areas are larger in women than in men.

Source: Human Brain Project

Researchers at the Human Brain Project (HBP) have mapped four new areas of the human anterior prefrontal cortex that play an important role in cognitive functions. Two of the newly identified areas are relatively larger in women than in men.

The human dorsolateral prefrontal cortex is involved in cognitive control including attentional selection, working memory, decision making, and action planning. Changes in this brain region are suspected to play a role in schizophrenia, obsessive-compulsive disorder, depression and bipolar disorder, making it an important research target.

Researchers from Forschungszentrum Jülich and Heinrich-Heine University Düsseldorf now provide detailed, three-dimensional maps of four new areas of the brain region.

Probability maps of the four newly identified areas SFS1, SFS2, MFG1 and MFG2. Credit: Bruno et al

In order to identify the boundaries between brain areas, the researchers statistically analyzed the distribution of cells (cytoarchitecture) in 10 post-mortem human brains. After reconstructing the mapped areas in 3D, the researchers overlaid the maps from the 10 different brains and generated probability maps that reflect how much the location and size of each area varies between individuals.

High intersubject variability has been a major challenge for previous attempts to map this brain region, resulting in considerable discrepancies in preexisting maps and inconclusive information that makes it very difficult to understand the specific involvement of individual brain areas in different cognitive functions.

The new probabilistic maps account for inter-individual variability and can be directly overlaid with datasets from functional studies to directly correlate the structure and function of areas.

When the brains of female and male tissue donors were compared, the researchers found that the relative volumes of two of the newly identified areas were significantly larger in female brains than in male brains. This finding may be related to sex differences in cognitive function and behavior, as well as in the prevalence and symptoms of associated brain diseases.

The maps are being integrated into the Julich Brain Atlas which is openly accessible through EBRAINS.

About this brain mapping research news

Author: Peter Zekert
Source: Human Brain Project
Contact: Peter Zekert – Human Brain Project
Image: Image is credited to Bruno et al

Original Research: Open access
“Cytoarchitecture, intersubject variability, and 3D mapping of four novel areas of the human anterior prefrontal cortex” by Bruno et al. Frontiers in neuroanatomy


Summary

Cytoarchitecture, intersubject variability, and 3D mapping of four novel areas of the human anterior prefrontal cortex

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The dorsolateral prefrontal cortex (DLPFC) plays a key role in cognitive control and executive functions such as working memory, attention, value encoding, decision making, monitoring, and control strategies. behavior However, the relationships between this variety of functions and the underlying cortical areas, which specifically contribute to these functions, are still not well understood.

Existing microstructural maps differ in the number, location, and extent of DLPFC areas. Furthermore, there is considerable intersubject variability in both the sulcal pattern and the microstructure of this region, which precludes comparison with functional neuroimaging studies.

The aim of this study was to provide microstructural and cytoarchitectonic maps of the human anterior DLPFC in 3D space. We therefore analyzed 10 postmortem human brains and mapped their borders using a well-established approach based on statistical image analysis. Four novel areas (i.e., SFS1, SFS2, MFG1, and MFG2) were identified in serial cell body-stained brain sections that occupy the superior anterior frontal sulcus and middle frontal gyrus, i.e., a region corresponding to parts of Brodmann areas 9 and 46.

Differences between areas in cytoarchitecture were captured using gray-level index profiles, which reflect changes in the volume fraction of cell bodies from the surface of the brain to the edge of the cortex and white matter

A hierarchical cluster analysis of these profiles indicated that anterior DLPFC areas showed greater cytoarchitectonic similarity with each other than with neighboring frontal pole areas (areas Fp1 and Fp2), Broca’s region (areas 44 and 45 ) of the ventral prefrontal cortex, and posterior DLPFC areas (8d1, 8d2, 8v1 and 8v2).

Area-specific cytoarchitectonic differences were found between male and female brains. Individual areas were reconstructed in 3D and probability maps were created in MNI Colin27 and ICBM152casym reference spaces to account for the variability of areas in stereotaxic space.

The new maps contribute to Julich-Brain and are publicly available as a resource for studying neuroimaging data, helping to clarify the functional and organizational principles of the human prefrontal cortex.

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