Surfin’ endocasts: The good and the bad on brain form

Bruner, Emiliano; Ogihara, Naomichi

doi:10.26879/805

Cited by 7 publications

(7 citation statements)

References 51 publications

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“…Therefore, overall shape analyses should be limited to preliminary geometrical surveys. More detailed morphometrics, based on anatomical boundaries, should be used to test specific hypotheses in evolutionary neuroanatomy [Bruner and Ogihara, 2018]. Fifth, more information is needed about modern human variation.…”

Section: Perspectivesmentioning

confidence: 99%

Human Paleoneurology and the Evolution of the Parietal Cortex

Bruner¹

2018

Brain Behav Evol

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Paleoneurology deals with the study of brain anatomy in fossil species, as inferred from the morphology of their endocranial features. When compared with other living and extinct hominids, Homo sapiens is characterized by larger parietal bones and, according to the paleoneurological evidence, also by larger parietal lobes. The dorsal elements of the posterior parietal cortex (superior parietal lobules, precuneus, and intraparietal sulcus) may be involved in these morphological changes. This parietal expansion was also associated with an increase in the corresponding vascular networks, and possibly with increased heat loads. Only H. sapiens has a specific early ontogenetic stage in which brain form achieves such globular appearance. In adult modern humans, the precuneus displays remarkable variation, being largely responsible for the longitudinal parietal size. The precuneus is also much more expanded in modern humans than in chimpanzees. Parietal expansion is not influenced by brain size in fossil hominids or living primates. Therefore, our larger parietal cortex must be interpreted as a derived feature. Spatial models suggest that the dorsal and anterior areas of the precuneus might be involved in these derived morphological variations. These areas are crucial for visuospatial integration, and are sensitive to both genetic and environmental influences. This article reviews almost 20 years of my collaborations on human parietal lobe evolution, integrating functional craniology, paleoneurology, and evolutionary neuroanatomy.

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Section: Perspectivesmentioning

confidence: 99%

Human Paleoneurology and the Evolution of the Parietal Cortex

Bruner¹

2018

Brain Behav Evol

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“…; Kobayashi et al. ; Minh & Hamada, ; Bruner & Ogihara, ). Controversy also surrounds early descriptions of these patterns in fossil endocasts, which mostly relied on visual inspection and palpation of the endocranial surface (Falk, ,b, ; Holloway, ).…”

Section: Introductionmentioning

confidence: 98%

Sulcal pattern variation in extant human endocasts

et al. 2019

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Our knowledge of human brain evolution primarily relies on the interpretation of palaeoneurological evidence. In this context, an endocast or replica of the inside of the bony braincase can be used to reconstruct a timeline of cerebral changes that occurred during human evolution, including changes in topographic extension and structural organisation of cortical areas. These changes can be tracked by identifying cerebral imprints, particularly cortical sulci. The description of these crucial landmarks in fossil endocasts is, however, challenging. High-resolution imaging techniques in palaeoneurology offer new opportunities for tracking detailed endocranial neural characteristics. In this study, we use high-resolution imaging techniques to document the variation in extant human endocranial sulcal patterns for subsequent use as a platform for comparison with the fossil record. We selected 20 extant human crania from the Pretoria Bone Collection (University of Pretoria, South Africa), which were detailed using X-ray microtomography at a spatial resolution ranging from 94 to 123 lm (isometric). We used ENDEX to extract, and MATLAB to analyse the cortical imprints on the endocasts. We consistently identified superior, middle and inferior sulci on the frontal lobe; and superior and inferior sulci on the temporal lobe. We were able to label sulci bordering critical functional areas such as Broca's cap. Mapping the sulcal patterns on extant endocasts is a prerequisite for constructing an atlas which can be used for automatic sulci recognition.

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“…The use of these sparse clouds of points (semilandmarks and sliding landmarks) has represented a major advance in paleoneurology, although this option is sensitive to the same limitations of the two methods. All these techniques that rely on curves and surfaces are extremely efficient to analyze the overall geometry of the object under study, but not always efficient in localizing the actual anatomical factors involved in those variations (Bruner & Ogihara, ). That is, when using curves and surfaces, shape analysis is computed to compare “objects”, and not anatomical systems.…”

Section: Digital Anatomy and Computed Morphometricsmentioning

confidence: 99%

Human paleoneurology: Shaping cortical evolution in fossil hominids

Bruner

2019

J of Comparative Neurology

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Evolutionary neuroanatomy must integrate two different sources of information, namely from fossil and from living species. Fossils supply information concerning the process of evolution, whereas living species supply information on the product of evolution. Unfortunately, the fossil record is partial and fragmented, and often cannot support validations for specific evolutionary hypotheses. Living species can provide more comprehensive indications, but they do not represent ancestral groups or primitive forms. Macaques or chimpanzees are frequently used as proxy for human ancestral conditions, despite the fact they are divergent and specialized lineages, with their own biological features. Similarly, in paleoanthropology independent lineages (such as Neanderthals) should not be confused with ancestral modern human stages. In this comparative framework, paleoneurology deals with the analysis of the endocranial cavity in extinct species, in order to make inferences on brain evolution. A main target of this field is to distinguish the endocranial variations due to brain changes, from those due to cranial constraints. Digital anatomy and computed morphometrics have provided major advances in this field. However, brains and endocasts can be hard to analyze with geometrical models, because of uncertainties due to the localization of cortical landmarks and boundaries. The study of the evolution of the parietal cortex supplies an interesting case‐study in which paleontological and neontological data can integrate and test evolutionary hypotheses based on multiple sources of evidence. The relationships with visuospatial functions and brain–body–tool integration stress further that the analysis of the cognitive system should go beyond the neural boundaries of the brain.

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Surfin’ endocasts: The good and the bad on brain form

Cited by 7 publications

References 51 publications

Human Paleoneurology and the Evolution of the Parietal Cortex

Human Paleoneurology and the Evolution of the Parietal Cortex

Sulcal pattern variation in extant human endocasts

Human paleoneurology: Shaping cortical evolution in fossil hominids

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