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Study compares the parietal lobes in Neanderthals and modern humans


The Paleoneurobiology Group of the Centro Nacional de Investigacion sobre la Evolucion Humana (CENIEH), led by Emiliano Bruner, has just published a morphological analysis of the brains of Neanderthals and modern humans in the Journal of Human Evolution, whose results suggest that the more rounded shape of modern human brains is due in part to larger and bulgier parietal lobes, on average.

Study compares the parietal lobes in Neanderthals and modern humans
Neanderthal and Homo sapiens brains [Credit: Pereira Pedro et al. 2020]



Two regions in particular may be more highly developed in homo sapiens. The first is the dorsal posterior parietal region, and the second is the intermediate area of the intraparietal sulcus, in the inferior parietal lobule, says Sofia Pereira, who coordinated this study in collaboration with the Max Planck Institute in Leipzig (Germany).

The study was conducted using three-dimensional spatial models, which have enabled comparison of brain shape in 52 modern humans with that in eight Neanderthals, employing endocranial casts and the impressions left by the cerebral sulci on the surface of the braincase. The geometric model not only includes information on the general shape of the brain, but also the specific locations of the parietal anatomy.

The parietal lobes are implicated in visuospatial functions such as visual imagination and handling, and in general in all those cognitive aspects relating to coordination between brain, body and external environment, including the eye-hand relationship and that between hand and tools.


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2 comments :

  1. Very interesting study, thanks a lot. It's now becoming more & more clear that neandertals were probably no tundra hunters: different indications show that they got most foods from waterside & shallow-aquatic milieus, e.g. traces of waterlilies in dental plaque (Spy), traces of cattails on their tools, C & N isotopes halfway littoral & freshwater foods (in European neandertals), projecting mid-face (maladaptive in tundra, Allen's rule), platycephaly (long low flat brain-skull) & pachy-osteo-sclerosis (typical of shallow-diving animals), extensive ear exostoses (typical of human surfers & divers), brain enlargement (DHA in aquatic foods), diving for shellfish in Latium (Villa cs 2020 PLoS ONE doi org/10.1371/journal.pone.0226690) etc. For a recent review & refs, google "coastal dispersal of Pleistocene Homo 2018 biology vs anthropocentrism".
    There might of course be some limited brain differences between us & them (esp. in language areas in the parietal cortex?), but as in other frequently-diving animals, the neandertal brain-skull underwent selection for an externally long low flat form (platycephaly) which had little to do with the brain contents inside. When this selection for an elongated skull form disappeared in H.sapiens when we no longer frequently dived, we got again the best architectural skull form for protecting our brain: our globular brain-skull. The archaic osteosclerosis (as in other shallow-diving spp) also disappeared in H.sapiens, and the combination of globularization & loss of osteeosclerosis could explain the skull "gracilization" we see in H.sapiens. The reduction of diving in early H.sapiens also "freed" the airways, which might have facilitated human speech (google "speech and language evolution 2018 verhaegen").
    IMO, hominids evolution is not so difficult if we stop considering ourselves as special creatures (anthropocentrism), but simply study hominid fossils like we study other animals, see my paper in Hum.Evol.28:237-266 "The aquatic ape evolves: common misconceptions and unproven assumptions about the so-called Aquatic Ape Hypothesis".

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    1. This is very clever and inventive hypothesis however is scientifically unsound. You are basing your theory on a small group of individuals which may not be true for all. Also it is highly unlikely that the shape of our skulls will change shape due to an aquatic environment unless we were living in that environment permanently like maybe seals. Perhaps you are putting too much emphasis on the hunter rather than the gatherer.

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