Extending mind, visuospatial integration, and the evolution of the parietal lobes in the human genus

Bruner, Emiliano; Iriki, Atsushi

doi:10.1016/j.quaint.2015.05.019

Cited by 97 publications

(83 citation statements)

References 109 publications

(115 reference statements)

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“…The medial parietal cortex is also implicated in higher cognitive processes such as autobiographical memory retrieval, theory of mind and self-reflection (Cavanna and Trimble 2006; Schneider et al 2014). The precuneus is also essential in visuospatial functions which are central for the integration between brain, body, and environment, as for managing internal cognitive models (Land 2014; Bruner and Iriki 2015; Peer et al 2015). Current perspectives in cognitive sciences suggest that the integration between body and environment is also crucial to coordinate spatial and chronological processes with social perception (Hills et al 2015; Maister et al 2015).…”

Section: Discussionmentioning

confidence: 99%

Evidence for expansion of the precuneus in human evolution

et al. 2016

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The evolution of neurocranial morphology in Homo sapiens is characterized by bulging of the parietal region, a feature unique to our species. In modern humans, expansion of the parietal surface occurs during the first year of life, in a morphogenetic stage which is absent in chimpanzees and Neandertals. A similar variation in brain shape among living adult humans is associated with expansion of the precuneus. Using MRI-derived structural brain templates, we compare medial brain morphology between humans and chimpanzees through shape analysis and geometrical modeling. We find that the main spatial difference is a prominent expansion of the precuneus in our species, providing further evidence of evolutionary changes associated with this area. The precuneus is a major hub of brain organization, a central node of the default-mode network, and plays an essential role in visuospatial integration. Together, the comparative neuroanatomical and paleontological evidence suggest that precuneus expansion is a specialization of Homo sapiens that evolved in the last 150,000 years that may be associated with recent human cognitive specializations.

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Section: Discussionmentioning

confidence: 99%

Evidence for expansion of the precuneus in human evolution

et al. 2016

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“…Strong selection for larger brains has been linked to the selective advantages associated with the enhanced computational abilities of a larger neocortex with more neurons (32), but it also can be linked to other neural modifications such as an increased level of developmental plasticity arising from changes in the developmental patterns associated with larger brains (28,33,34). Selection for certain aspects of brain organization, particularly in the upper parietal reorganization that is arguably associated with modern human-specific functional modifications (17), is confined primarily to the branch leading directly to H. sapiens. No other aspects of brain reorganization as described by our set of variables show evidence of fast evolution across the hominin clade.…”

Section: Discussionmentioning

confidence: 99%

“…The eigenvector of this axis shows that the dorsal arc connecting the frontal and occipital poles is the only variable loading positively on PC1, thus separating flatter from the more globular endocasts that distinguish H. sapiens (Table S4) (14)(15)(16). Although frontal changes also can influence this variable, researchers have suggested that globularization is driven by upper parietal reorganization and that this anatomical change can be associated with enhanced visuospatial integration and memory in modern humans (17). The comparatively fast evolution of the dorsal arc trait in the lineage leading to H. sapiens is consistent with such a link between brain anatomy and function, although it could be an indirect result of selection on other craniofacial hard-tissue changes (18).…”

Section: Significancementioning

confidence: 99%

Brain enlargement and dental reduction were not linked in hominin evolution

Gómez‐Robles

Smaers

Holloway

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The large brain and small postcanine teeth of modern humans are among our most distinctive features, and trends in their evolution are well studied within the hominin clade. Classic accounts hypothesize that larger brains and smaller teeth coevolved because behavioral changes associated with increased brain size allowed a subsequent dental reduction. However, recent studies have found mismatches between trends in brain enlargement and posterior tooth size reduction in some hominin species. We use a multiple-variance Brownian motion approach in association with evolutionary simulations to measure the tempo and mode of the evolution of endocranial and dental size and shape within the hominin clade. We show that hominin postcanine teeth have evolved at a relatively consistent neutral rate, whereas brain size evolved at comparatively more heterogeneous rates that cannot be explained by a neutral model, with rapid pulses in the branches leading to later Homo species. Brain reorganization shows evidence of elevated rates only much later in hominin evolution, suggesting that fast-evolving traits such as the acquisition of a globular shape may be the result of direct or indirect selection for functional or structural traits typical of modern humans.endocast | postcanine teeth | evolutionary rates | selection | paleoanthropology I n comparison with other hominins, modern humans are characterized by their large brain and small posterior teeth. These traits are among our most distinctive features, and trends in their evolution are well studied because of the phylogenetic and functional implications of variation in dental and cerebral anatomy (1-3). Brain expansion and postcanine reduction appear to follow parallel trends during hominin evolution, and classic views consider that an increase in brain size was linked to more complex behavior that included the manufacture and use of stone tools, which allowed a subsequent dental reduction. A shift toward a higher-quality diet during the evolution of early Homo also has been related to brain size increase and posterior tooth reduction (4, 5). However, it has been suggested recently that brain expansion in early Homo, as inferred from endocranial volume, substantially preceded dental reduction (6). It also has been noted that early in the Neanderthal lineage strong dental reduction preceded the additional brain expansion seen in the later "classic" Neanderthals (7). The suggestion that stone tool use and manufacture substantially predated the increase in brain size observed in early Homo (8) adds further complexity to this scenario.Recent developments in ancestral state reconstruction (9, 10) allow lineage-specific patterns of brain expansion and dental reduction to be quantified and compared. Unlike traditional approaches to ancestral state reconstruction that assume a neutral evolutionary scenario, which is likely unrealistic in most cases, we used a variable rate approach that estimates differences in evolutionary rates across different branches of a given phylogeny. We appli...

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“…Our technology is actually part of our cognitive processes, and there are several theories in current neuroscience interpreting cognition as the result of integration between brain, body, and tools [Malafouris, 2010;Iriki and Taoka, 2012;Byrge et al, 2014]. In this sense, our parietal cortex and visuospatial functions can play a major role in the management of such interactions between the nervous system, the body interface, and technological resources [Bruner and Iriki, 2016]. Interestingly, a comprehensive analysis on neural circuits in primates evidenced major human changes in the genetic expression associated with the striatum, an element of the basal ganglia deeply involved in body management [Sousa et al, 2017].…”

Section: Visuospatial Integration and Body Cognitionmentioning

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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Extending mind, visuospatial integration, and the evolution of the parietal lobes in the human genus

Cited by 97 publications

References 109 publications

Evidence for expansion of the precuneus in human evolution

Evidence for expansion of the precuneus in human evolution

Brain enlargement and dental reduction were not linked in hominin evolution

Human Paleoneurology and the Evolution of the Parietal Cortex

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