These are excerpts and elaborations from my book "The Nature of Consciousness"
An Olfactory Brain The US neuroscientist Rhawn
Joseph argued that the human brain
still contains parts that were used by animals that lived hundreds of million
of years ago. In other words, we share parts of the brain of many other
animals, and, ultimately, one can say that all animals are “linked” by the
“collectively shared unconscious” Joseph calls the human body a “living
museum” because it contains so many remnants of ancient organs. This is also
visible in language: while we have developed sophisticated spoken languages, we
still use gestures, that are presumably an archaic form of communication. Old
and new languages coexist. We often communicate unconsciously to other beings
precisely because we still have, like it or not, the old languages. For
example, a facial expression is enough to communicate our state of mind. Neurons
(nerve cells) first appeared 700
million years ago. When neurons got connected, the first brain was born. Joseph believes that the first major grouping of
neurons occurred among olfactory cells, that originally may have been external
cells. Eventually they migrated inside the body and created an olfactory lobe.
Later, a similar fate turned visual cells into the visual lobe. The growth of
these two lobes over evolutionary time eventually yielded the brain as we know
it (the two hemispheres). The olfactory lobe also
evolved into the limbic lobe, that still controls many of the “instinctive”
activities (in both humans and other animals). The cells of the limbic lobe
created more and more layers, and eventually created the cortex. Thus the
fundamental structure of the modern human brain evolved from the olfactory
lobe. Among the various forms of
communication that are crucial to our understanding of the world, Joseph believes that odors play an
important role. The nose contains the most exposed (unprotected) neurons of the
human body. The mucosa of the nose is directly connected to the hippocampus and
the amygdala, which are instrumental in creating memories. It is likely that
living beings developed the ability to analyze chemicals (odors) in order to
understand changes in the environment and to sense other beings (in fact, our
bodies still excrete odor-generating chemicals from the skin). Odors, after
all, control sex and aggression and many other basic activities of most
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