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Svante Pääbo, director of evolutionary genetics at the Max Planck Institute for Evolutionary Anthropology. Photograph: Christian Jungeblodt

Svante Pääbo, director of evolutionary genetics at the Max Planck Institute for Evolutionary Anthropology. Photograph: Christian Jungeblodt

Svante Pääbo, director of the genetics department at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany wants to grow brain organoids from human stem cells that are edited to contain “Neanderthalized” versions of several genes. These blobs of brain are incapable of thoughts or feelings, but replicate basic structures of the brain, such as how nerve cells function. This may provide a basis for why humans seem to be cognitively so special. The lab has already successfully inserted Neanderthal genes for craniofacial development into mice (heavy-browed rodents are not anticipated) as well as Neanderthal pain perception genes into frogs’ eggs, which could hint at whether they had a different pain threshold to humans.

Majkic et al. 2018

Majkic et al. 2018

Which leads me to share two other similar studies that looked at Neanderthal cognition in different ways. The first is a report in PLoS One of evidence for symbolic thought among Neanderthals from a 3.5cm-long thin flake that is 35,486 and 37,026 years old and was found from the Kiik-Koba Cave which overlooks the Zuya River in the Crimean Mountains. A group of archaeologists, actually Ana Majkic and her colleagues, claims those uneven lines are a deliberate marking.

At first glance, the 13 lines etched in the chalky outer layer of the flake look messy and haphazard. Some of them are straight. Some are slightly curved. The remainder overlap or are superimposed over others. It’s really hard to make out individual lines with the naked eye. But microscopic analysis tells a different story. It turns out that the lines were etched with a pointed stone tool, which produced clean-edged incisions with a V-shaped cross-section that shows up clearly under a microscope. Some of those cross-sections are asymmetrical in a way that hints at a right-handed craftsman holding the etching tool. Most of the lines have clear starting points where the grooves are deeper but then fade toward the far ends. By looking at which lines cross or cover others, Majkic and her colleagues were able to see the order in which the marks have been made… these lines were made deliberately—but they were still hasty work.

The second Neanderthal looks at the differences between humans and Neandethal cognition thru a comparative analysis of Neanderthal and early modern human skull anatomy to infer brain function. This research was published in Scientific Reports and ultimately. Working under the assumption that behavior is a function of cognitive and neurological capacities, a team of researchers led by Naomichi Ogihara from Keio University in Japan set out to model the brains of Neanderthals, early anatomically modern humans, and living humans to infer possible functional differences between the two. Prior to this work, scientists had analyzed the differences between Neanderthal and modern human brains, but this is the first study to reconstruct brains for the purpose of postulating possible functional differences.

Ogihara’s team created virtual three-dimensional “casts” of brains using data derived from the skulls of four Neanderthals and four early modern humans (the skulls used in the study dated from between 135,000 and 32,000 years ago). This allowed the researchers to reconstruct and visualize the 3D structure of the brain’s grey and white matter regions, along with the cerebrospinal fluid regions. Then, using a large dataset from the Human Connectome Project, specifically MRI brain scans taken of more than 1,180 individuals, the researchers modeled the “average” human brain to provide a kind of baseline for the study and allow for the comparative analysis.

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Using this method, the researchers uncovered “significant” differences in brain morphology. Even though Neanderthals had larger skulls, and thus larger brain volume overall, H. sapiens had a proportionately larger cerebellum, the part of brain involved in movement, balance, vision, learning, language, and mood. Modern humans also featured a smaller occipital region in the cerebrum, which is tied to vision. Looking at these differences, the researchers inferred such abilities as cognitive flexibility (i.e. learning, adaptability, and out-of-the-box thinking), attention, language processing, and short-term and long-term memory. Homo sapiens, the researchers concluded, had better cognitive and social abilities than Neanderthals, and a greater capacity for long-term memory and language processing. This all suggests important differences in cognitive and neural function between Homo sapiens and Neanderthals led to differences in behavior that may have resulted in the conditions under which anatomically modern humans succeeded and Neanderthals failed some 45,000 years ago.

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