What is surprising is that the
differences between the brains are that significant and that we also learn that
olfactory stimulus is linked to memory and emotion. It is all very suggestive and supports a
whole of conjectures that are unfortunately just that. It also places a much sharper divide between
been Human and been Neanderthal.
Up to this point there was little
reason to argue a serious difference in mental capabilities simply because of
the similarity of brain weight. Now it
is quite the opposite and all sorts of interesting question spring to mind.
What is presently lacking from
the fossil record is a circa 200,000 BCE sampling of primates based in the
tropics. One would like to see the
likely progenitor(s) of humanity with some level of assurance. We see post 100,000 BCE when the big shift
had taken place and we have an either Neanderthal or Human.
Was Humanity a genetic derivative
plausibly engineered from the Neanderthal linage? We have lots of reason to
think not, but that discounts the engineering option that some folks like. My sense is that the Neanderthal already was
adapted to the necessary brain size and made a natural choice to produce the
desired end product. Thus I would like
to see other equivalents.
In passing, genetic work strongly
supports the engineered argument, but no one talks about it because it is
hugely controversial to say the least.
Follow your nose
by Staff Writers
Shape differences in the brains of an adult homo sapiens (blue) and an
adult Neanderthal (red). Image courtesy MPI for Evolutionary
Anthropology/Phillip Gunz.
Differences in the temporal lobes and olfactory bulbs also suggest a
combined use of brain functions related
to cognition and olfaction. The increase of brain size is intimately linked to
the evolution of humanity. Two different human species, Neanderthals and modern
humans, have independently evolved brains of roughly the same size but with
differing shapes. This could indicate a difference in the underlying brain
organization.
In a study published
this week by Nature Communications, led by Markus Bastir and Antonio Rosas, of
the Spanish Natural Science
Museum
The researchers used sophisticated 3D methods to quantify the shape of
the basal brain as reflected in the morphology of the skeletal cranial base.
Their findings reveal that the human temporal lobes, involved in language,
memory and social functions as well as the olfactory bulbs are relatively
larger in Homo sapiens than in Neanderthals.
"The structures which receive olfactory input are approximately
12% larger in modern humans than in Neanderthals", the authors explain.
These findings may have important implications for olfactory capacity
and human behaviour. In modern humans the size of the olfactory bulbs is
related to the capacity of detection and
discrimination of different smells. Olfaction is among the oldest sense in
vertebrates.
"Also, it is the only one that establishes a direct connection
between the brain and its environment", says Markus Bastir, the lead
author of the study. While other senses must pass through different cortical
filters, olfaction goes from the environment right into the highest centres of
the brain.
What is more, "olfaction never sleeps", adds Antonio Rosas,
"because we always breathe and perceive smells". The neuronal
circuitry of olfaction coincides with that of memory and emotion (the limbic
system), "which explains the enormous memory retention and vital intensity
of olfaction-mediated life events."
Researchers at the Max Planck Institute for Evolutionary Anthropology
in Leipzig, who also contributed to the current publication, could recently
show differences in the patterns of brain development between modern humans and
Neanderthals during a critical phase for cognitive development.
"In the first year of life the brains of Neanderthals and modern
humans develop differently," says Philipp Gunz from the Max Planck
Institute of Evolutionary Anthropology in Leipzig
"Evidence is accumulating that Neanderthals and modern humans
independently evolved large brains and that their brains might have worked
differently. Our new study offers a glimpse into the functional significance of
these developmental differences," adds Jean-Jacques Hublin, who heads the
Department of Human Evolution at the Max Planck Institute of Evolutionary
Anthropology in Leipzig.
Olfactory information projects to
brain regions directly responsible for processing of emotion, motivation, fear,
memory, pleasure and also attraction. Neuroscientists have coined the term
"higher olfactory functions" to describe those brain functions which combine
cognition (memory, intuition, perception, judgment) and olfaction.
The greater olfactory bulbs and relatively larger temporal lobes in H.
sapiens compared to any other human species may point towards improved and
different olfactory sense possibly related to the evolution of behavioural
aspects and social functions.
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