Distribution of neurons across functional areas in the mouse cerebral cortex reveals quantitatively different cortical zones
How are neurons distributed along the cortical surface and across functional areas? Here we use the isotropic fractionator (Herculano-Houzel and Lent, 2005) to analyze the distribution of neurons across the entire isocortex of the mouse, divided into 18 functional areas defined anatomically. We find...
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| Format: | Journal Article |
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Frontiers Research Foundation
2013
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| Online Access: | http://hdl.handle.net/20.500.11937/25952 |
| _version_ | 1848751848856485888 |
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| author | Herculano-Houzel, S. Watson, Charles Paxinos, G. |
| author_facet | Herculano-Houzel, S. Watson, Charles Paxinos, G. |
| author_sort | Herculano-Houzel, S. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | How are neurons distributed along the cortical surface and across functional areas? Here we use the isotropic fractionator (Herculano-Houzel and Lent, 2005) to analyze the distribution of neurons across the entire isocortex of the mouse, divided into 18 functional areas defined anatomically. We find that the number of neurons underneath a surface area (the N/A ratio) varies 4.5-fold across functional areas and neuronal density varies 3.2-fold. The face area of S1 contains the most neurons, followed by motor cortex and the primary visual cortex. Remarkably, while the distribution of neurons across functional areas does not accompany the distribution of surface area, it mirrors closely the distribution of cortical volumes—with the exception of the visual areas, which hold more neurons than expected for their volume. Across the non-visual cortex, the volume of individual functional areas is a shared linear function of their number of neurons, while in the visual areas, neuronal densities are much higher than in all other areas. In contrast, the 18 functional areas cluster into three different zones according to the relationship between the N/A ratio and cortical thickness and neuronal density: these three clusters can be called visual, sensory, and, possibly, associative.These findings are remarkably similar to those in the human cerebral cortex (Ribeiro et al., 2013) and suggest that, like the human cerebral cortex, the mouse cerebral cortex comprises two zones that differ in how neurons form the cortical volume, and three zones that differ in how neurons are distributed underneath the cortical surface, possibly in relation to local differences in connectivity through the white matter. Our results suggest that beyond the developmental divide into visual and non-visual cortex, functional areas initially share a common distribution of neurons along the parenchyma that become delimited into functional areas according to the pattern of connectivity established later. |
| first_indexed | 2025-11-14T07:59:15Z |
| format | Journal Article |
| id | curtin-20.500.11937-25952 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:59:15Z |
| publishDate | 2013 |
| publisher | Frontiers Research Foundation |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-259522017-09-13T15:23:04Z Distribution of neurons across functional areas in the mouse cerebral cortex reveals quantitatively different cortical zones Herculano-Houzel, S. Watson, Charles Paxinos, G. occipital cortex numbers of neurons mouse cortical development neuronal density visual cortex How are neurons distributed along the cortical surface and across functional areas? Here we use the isotropic fractionator (Herculano-Houzel and Lent, 2005) to analyze the distribution of neurons across the entire isocortex of the mouse, divided into 18 functional areas defined anatomically. We find that the number of neurons underneath a surface area (the N/A ratio) varies 4.5-fold across functional areas and neuronal density varies 3.2-fold. The face area of S1 contains the most neurons, followed by motor cortex and the primary visual cortex. Remarkably, while the distribution of neurons across functional areas does not accompany the distribution of surface area, it mirrors closely the distribution of cortical volumes—with the exception of the visual areas, which hold more neurons than expected for their volume. Across the non-visual cortex, the volume of individual functional areas is a shared linear function of their number of neurons, while in the visual areas, neuronal densities are much higher than in all other areas. In contrast, the 18 functional areas cluster into three different zones according to the relationship between the N/A ratio and cortical thickness and neuronal density: these three clusters can be called visual, sensory, and, possibly, associative.These findings are remarkably similar to those in the human cerebral cortex (Ribeiro et al., 2013) and suggest that, like the human cerebral cortex, the mouse cerebral cortex comprises two zones that differ in how neurons form the cortical volume, and three zones that differ in how neurons are distributed underneath the cortical surface, possibly in relation to local differences in connectivity through the white matter. Our results suggest that beyond the developmental divide into visual and non-visual cortex, functional areas initially share a common distribution of neurons along the parenchyma that become delimited into functional areas according to the pattern of connectivity established later. 2013 Journal Article http://hdl.handle.net/20.500.11937/25952 10.3389/fnana.2013.00035 Frontiers Research Foundation fulltext |
| spellingShingle | occipital cortex numbers of neurons mouse cortical development neuronal density visual cortex Herculano-Houzel, S. Watson, Charles Paxinos, G. Distribution of neurons across functional areas in the mouse cerebral cortex reveals quantitatively different cortical zones |
| title | Distribution of neurons across functional areas in the mouse cerebral cortex reveals quantitatively different cortical zones |
| title_full | Distribution of neurons across functional areas in the mouse cerebral cortex reveals quantitatively different cortical zones |
| title_fullStr | Distribution of neurons across functional areas in the mouse cerebral cortex reveals quantitatively different cortical zones |
| title_full_unstemmed | Distribution of neurons across functional areas in the mouse cerebral cortex reveals quantitatively different cortical zones |
| title_short | Distribution of neurons across functional areas in the mouse cerebral cortex reveals quantitatively different cortical zones |
| title_sort | distribution of neurons across functional areas in the mouse cerebral cortex reveals quantitatively different cortical zones |
| topic | occipital cortex numbers of neurons mouse cortical development neuronal density visual cortex |
| url | http://hdl.handle.net/20.500.11937/25952 |