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Schuurman T, Bruner E. An inclusive anatomical network analysis of human craniocerebral topology. J Anat 2024. [PMID: 38822698 DOI: 10.1111/joa.14068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/19/2024] [Accepted: 05/13/2024] [Indexed: 06/03/2024] Open
Abstract
The human brain's complex morphology is spatially constrained by numerous intrinsic and extrinsic physical interactions. Spatial constraints help to identify the source of morphological variability and can be investigated by employing anatomical network analysis. Here, a model of human craniocerebral topology is presented, based on the bony elements of the skull at birth and a previously designed model of the brain. The goal was to investigate the topological components fundamental to the craniocerebral geometric balance, to identify underlying phenotypic patterns of spatial arrangement, and to understand how these patterns might have influenced the evolution of human brain morphology. Analysis of the craniocerebral network model revealed that the combined structure of the body and lesser wings of the sphenoid bone, the parahippocampal gyrus, and the parietal and ethmoid bones are susceptible to sustain and apply major spatial constraints that are likely to limit or channel their morphological evolution. The results also showcase a high level of global integration and efficient diffusion of biomechanical forces across the craniocerebral system, a fundamental aspect of morphological variability in terms of plasticity. Finally, community detection in the craniocerebral system highlights the concurrence of a longitudinal and a vertical modular partition. The former reflects the distinct morphogenetic environments of the three endocranial fossae, while the latter corresponds to those of the basicranium and calvaria.
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Affiliation(s)
- Tim Schuurman
- Centro Nacional de Investigación Sobre la Evolución Humana, Burgos, Spain
| | - Emiliano Bruner
- Centro Nacional de Investigación Sobre la Evolución Humana, Burgos, Spain
- Alzheimer's Centre Reina Sofía-CIEN Foundation-ISCIII, Madrid, Spain
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Sansalone G, Wroe S, Coates G, Attard MRG, Fruciano C. Unexpectedly uneven distribution of functional trade-offs explains cranial morphological diversity in carnivores. Nat Commun 2024; 15:3275. [PMID: 38627430 PMCID: PMC11021405 DOI: 10.1038/s41467-024-47620-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 04/08/2024] [Indexed: 04/19/2024] Open
Abstract
Functional trade-offs can affect patterns of morphological and ecological evolution as well as the magnitude of morphological changes through evolutionary time. Using morpho-functional landscape modelling on the cranium of 132 carnivore species, we focused on the macroevolutionary effects of the trade-off between bite force and bite velocity. Here, we show that rates of evolution in form (morphology) are decoupled from rates of evolution in function. Further, we found theoretical morphologies optimising for velocity to be more diverse, while a much smaller phenotypic space was occupied by shapes optimising force. This pattern of differential representation of different functions in theoretical morphological space was highly correlated with patterns of actual morphological disparity. We hypothesise that many-to-one mapping of cranium shape on function may prevent the detection of direct relationships between form and function. As comparatively only few morphologies optimise bite force, species optimising this function may be less abundant because they are less likely to evolve. This, in turn, may explain why certain clades are less variable than others. Given the ubiquity of functional trade-offs in biological systems, these patterns may be general and may help to explain the unevenness of morphological and functional diversity across the tree of life.
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Affiliation(s)
- Gabriele Sansalone
- Institute for Marine Biological Resources and Biotechnology (CNR-IRBIM), National Research Council, Via S. Raineri 4, 98122, Messina, Italy.
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia.
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 213D, 41125, Modena, Italy.
| | - Stephen Wroe
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Geoffrey Coates
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Marie R G Attard
- Function, Evolution and Anatomy Research Lab, Zoology Division, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
- British Antarctic Survey, High Cross, Madingley Road, CB3 0ET, Cambridge, UK
| | - Carmelo Fruciano
- Institute for Marine Biological Resources and Biotechnology (CNR-IRBIM), National Research Council, Via S. Raineri 4, 98122, Messina, Italy.
- National Biodiversity Future Center, Piazza Marina 61, 90133, Palermo, Italy.
- Department of Biological, Geological and Environmental Sciences, University of Catania, via Androne 81, 95124, Catania, Italy.
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Jeffery N, Manson A. Postnatal growth and spatial conformity of the cranium, brain, eyeballs and masseter muscles in the macaque (Macaca mulatta). J Anat 2023; 243:590-604. [PMID: 37300248 PMCID: PMC10485578 DOI: 10.1111/joa.13911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 05/15/2023] [Accepted: 05/26/2023] [Indexed: 06/12/2023] Open
Abstract
Spatial growth constraints in the head region can lead to coordinated patterns of morphological variation that pleiotropically modify genetically defined phenotypes as the tissues compete for space. Here we test for such architectural modifications during rhesus macaque (Macaca mulatta) postnatal ontogeny. We captured cranium and brain shape from 153 MRI datasets spanning 13 to 1090 postnatal days and tested for patterns of covariation with measurements of relative brain, eyeball, and masseter muscle size as well as callosal tract length. We find that the shape of the infant (<365 days) macaque cranium was most closely aligned to masseter muscle and brain size measured relative to face size. Infant brain and juvenile (365-1090 days) cranium shape were more closely linked with brain size relative to basicranium and face size. Meanwhile, the juvenile macaque brain shape was dominated by the size of the brain relative to that of the basicranium. Associations with relative eyeball size and commissural tract lengths were weaker. Our results are consistent with a spatial-packing regime operating during postnatal macaque ontogeny, in which relative growth of the masseter, face and basicranium have a greater influence than brain growth on the overall shape of the cranium and brain.
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Affiliation(s)
- Nathan Jeffery
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences (ILCaMS) and Human Anatomy Resource Centre (HARC), Education Directorate, University of Liverpool, Liverpool, UK
| | - Amy Manson
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences (ILCaMS) and Human Anatomy Resource Centre (HARC), Education Directorate, University of Liverpool, Liverpool, UK
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Jeffery NS, Humphreys C, Manson A. A human craniofacial life-course: Cross-sectional morphological covariations during postnatal growth, adolescence, and aging. Anat Rec (Hoboken) 2021; 305:81-99. [PMID: 34369671 DOI: 10.1002/ar.24736] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/19/2021] [Accepted: 06/30/2021] [Indexed: 01/22/2023]
Abstract
Covariations between anatomical structures are fundamental to craniofacial ontogeny, maturation, and aging and yet are rarely studied in such a cognate fashion. Here, we offer a comprehensive investigation of the human craniofacial complex using freely available software and MRI datasets representing 575 individuals from 0 to 79 years old. We employ both standard craniometrics methods as well as Procrustes-based analyses to capture and document cross-sectional trends. Findings suggest that anatomical structures behave primarily as modules, and manifest integrated patterns of shape change as they compete for space, particularly with relative expansions of the brain during early postnatal life and of the face during puberty. Sexual dimorphism was detected in infancy and intensified during adolescence with gender differences in the magnitude and pattern of morphological covariation as well as of aging. These findings partly support the spatial-packing hypothesis and reveal important insights into phenotypic adjustments to deep-rooted, and presumably genetically defined, trajectories of morphological size and shape change that characterize the normal human craniofacial life-course.
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Affiliation(s)
- Nathan S Jeffery
- Human Anatomy Resource Centre & Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Craig Humphreys
- Human Anatomy Resource Centre & Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Amy Manson
- Human Anatomy Resource Centre & Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
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