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Why did our ancient relatives, the Neanderthals, disappear, and why did our ancestors, early Homo sapiens, take over?
People have thrown around ideas like differences in dealing with climate change, social systems, language skills, and even cannibalism!
But some scientists think it might have to do with the brain differences between Neanderthals and early Homo sapiens, which could have led to changes in behaviour, ultimately giving our ancestors an edge.
We don't have Neanderthal brains lying around, but scientists used advanced computer techniques to virtually rebuild them based on their skulls. Think of it like solving a prehistoric brain puzzle! It's like using a time-travelling computer to simulate how our ancient relatives might have thought.
In a recent research, scientists used computational anatomy, to reconstruct the brains of Neanderthals and early modern humans based on fossil crania. They employed CT scan data, generating three-dimensional structures of brain surface.
Based on the reconstruction differences in the brain structure of Neanderthals and modern humans were explored. They used modern human brain maps as proxies for the last common ancestor of humans and Neanderthals, assuming similarities. The reconstructed brains showed that Neanderthals had smaller relative cerebellar volumes compared to Early and modern humans.
Morphological analysis revealed significant differences in the cerebellar, parietal, occipital, and medial temporal regions between Neanderthals and modern humans, with early humans showing intermediate features. The big difference they found is that in early humans and modern humans, a part of the brain called the cerebellum sticks out more at the bottom compared to Neanderthals. It's like saying our cerebellums have a "bump" at the bottom that Neanderthals don't have.
The cerebellum is crucial for attention, inhibition, cognitive flexibility, language processing, and memory. A bigger cerebellum is linked to better language processing and larger working memory capacity, suggesting that early modern humans might have had cognitive advantages over Neanderthals.
Interestingly, Neanderthal cerebellums showed an asymmetry, with the right side being significantly smaller than the left. This asymmetry might affect connections to the left prefrontal regions, crucial for language processing. However, this finding should be taken with caution due to potential preservation issues with Neanderthal fossils. Future studies with more cases are needed to confirm this asymmetry.
Scientists discovered that in modern human lineage, the parietal region was larger than in Neanderthals. This area helps us with tasks like imagining spaces and remembering things.
They also noticed differences in two other brain regions: the occipital and medial temporal areas. Neanderthals had larger parts of their brain related to vision in occipital region compared to early humans. Additionally, the shape of the base of the skull called basicranial morphology was different, especially around the temporal pole. This suggests that Neanderthals and early humans might have processed information differently in these areas.
In conclusion, Neanderthal had relatively smaller cerebellar hemispheres, especially on the right side, compared to Homo sapiens. Larger cerebellar hemispheres were associated with higher cognitive and social functions, potentially impacting language processing, working memory, and innovation.
Based on archaeological records, it was suggested that Neanderthal had a smaller working memory capacity, which is linked to cognitive flexibility. The differences in neuroanatomical organization, particularly in the cerebellum, may have contributed to variations in cognitive and social abilities between Neanderthals and Homo sapiens. This distinction could have affected their adaptability to a changing environment, potentially influencing survival and driving the replacement of Neanderthals by modern humans.
