Parietal lobes are a main source of morphological variation within humans and within hominids. This month we have published a study on the relationships between bones and lobes, to evaluate how and how much such variation in the cerebral areas can influence the variation of the corresponding cranial points. There is a size correlation between parietal bones and parietal lobes, but it is small. There is a lot of individual variation, most of all in the precuneus. Changes of the brain proportions do not seem to influence the spatial relationships of the bones. Therefore, when the boundaries of the parietal lobes change, the boundaries of the parietal bone do not. It is like the brain “slides” under the bones, without strict constraints due for example to the connective meningeal interface. So, the larger the parietal lobe, the more it approaches the frontal bone. Such lack of marked correspondence between bones and lobes suggest cautions when using cranial landmarks to estimate brain boundaries, like in neurosurgery or in paleoneurology. Now, two hypotheses can be put forward, taking into consideration that the growth of the parietal area in our species is characterized by a very early post-natal stage. First hypothesis: such lack of correspondence can be present since the beginning, and hence that early parietal bulging will separate the limits of the parietal lobe and bone. Second hypothesis: during that early stage parietal lobe and bone grow together (the latter in response to the former), but later stages of spatial changes in the anterior districts (frontal bone and lobe) alter their original correspondence. This study deals with modern humans, and it will be interesting to consider the same spatial relationships in other primates. Nonetheless, at least for Homo sapiens, we can say that between parietal lobes and parietal bones there is a good geometrical correspondence (overall curvature), a modest size correlation (length), and a variable spatial relationship (boundaries).
apes Atapuerca Australopithecus brain-artefact interface brain atlas brain biology braincase brain size brain thermoregulation CENIEH Cercopithecoids chimpanzee China cognitive archaeology corpus callosum cortical folding cortical surface cranial thickness diploic channels eLearning embodiment encephalization endocranial ontogeny endocranial volume evo-devo extended mind fossil endocasts Frederick Coolidge frontal bone frontal lobes functional craniology geometric morphometrics hemispheric asymmetries Holocene Homo erectus human ethology human genus intraparietal sulcus Konrad Lorenz Institute language Le Moustier macaque Malu Cave mammals metopic suture Mezmaiskaya modern humans myopia Neandertals occipital lobes orbits paleoneurology Pan paniscus Pan troglodytes parietal bone parietal lobes petalia Philipp Gunz Phillip Tobias photography precuneus primate brain sexual dimorphism shape analysis Simon Neubauer social primatology species concept subparietal sulcus sulcal patterns sulci symbolic thinking Taung child University of Colorado University of Liverpool visuospatial integration
- How big brains evolved could be revealed by new mathematical modelhttp://www.psypost.org/2017/03/big-brains-evolved-revealed-new-mathematical-model-48198
- DECODING MIMBRES PAINTINGThis extended abstract represents a summary introduction to a work in progress, which will culminate in a publication and exhibition at The Los Angeles County Museum of Art in 2018. It briefly outlines our discoveries and interpretations, which will be more fully presented, referenced and discussed in the forthcoming catalog. This presentation is available f […]
- Brain Volume DatabaseThe Internet Brain Volume Database (IBVD) is an online collection of neuroimaging data funded as a part of the international initiative, the Human Brain Project. The IBVD provides access data for both individual and among-group comparisons that allow total volume comparisons with parallelization of the brain into hemispheres, specific lobes or grey matter vo […]
- The Effect of Diet Changes and The Selection of European Fatty Acid DesaturasesUC Berkeley Integrative Biologist, Rasmus Nielsen and his colleagues, published a fascinating study in the journal Molecular Biology and Evolution looking at …Continue reading →
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- How to become a super memorizer – and what it does to your brainNew research shows that we can train our brains to become memory champions To many of us, having to memorize a long list of items feels like a chore. But for others, it is more like a sport. Every year, hundreds of these ‘memory athletes’ compete with one another in the World Memory Championships, memorising hundreds of words, numbers, or other pieces of inf […]
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