under the inner wall of the temporal lobe of the neocortex, the
hippocampus is one of the oldest cortical structures. Its main
function seems to be the consolidation of declarative
memory--memories that are fundamentally relational and
multidimensional, as opposed to procedural memory, whose
repetitive movements, "dedicated and inflexible...cannot
be manipulated or used in novel circumstances,"1 It
is believed that the hippocampus "could trigger your cortex
to run through some of its recent routines and thereby solidify
them" unconsciously. Perhaps they could even appear "as
a nighttime dream."2
Hippocampus derives from Greek for seahorse, or monster, as its
structure resembles this strange creature While some older anatomists associated the hippocampus with
the Egyptain god Ammon, or Amun. Thus, cornu ammonis, Ammon's
Horn. The buttons on the Contents page of this segment contain an
image of Alexander the Great wearing Ammon's horns.
also seems to be involved in orienting the organism in its environment
by creating spatial clues, or "place
fields," even while internally it displays an itinerant
Sacred to Ammon is a
fat-tailed species of ram--ovis platyura aegyptiaca, whose
horns are large, curved and downturned-- that is found only in
the area of the Sceptre Nome, Egypt.
though it's been long thought that adult brain cells cannot be
replaced, using a diagnostic method developed for cancer research
that labels dividing cells, nascent hippocampi neurons have been
discovered in adult human brains.3
Ammon was never
portrayed in the form of a ram, or as a man with a ram's head, he
always appeared inhuman shape, wearing a cap with two tall plumes
and a sun's disk. The Egyptian hieroglyph for
ram, ur-am, means 'solar heat'. In Indian schema, the Manipura
chakra lies in the area of the solar plexus, known of the "second
mind." Its center contains the ram, the symbol of Agni,
god of fire.
hippocampus is vunerable to post-traumantic
stress, such as caused by physical and/or emotional abuse,
along with ironically integrating "individual stimuli
into a context that no longer contains the individual elements...but
relations between stimuli."4 Finally,
hippocampal consolidation opens memories to the organism as
a whole, along with speculation that this organ conducts
our strange capacity for synesthesia.
The horn's iconology traces mythological figures, both virtuous
and notorious, from the Horned Moses (4) Hermes, the boundary keeper, to Satan, the seducer.
H. Eichenbaum and T. Otto, "The Hippocampus-What
Does It Do?" Behavioral and Neural Biology 57
(2) W.H. Calvin and G.A. Ojemann, Conversations with Neil's Brain.
MA., 1994. p.134.
(3) G. Kempermann and
F.H. Gage, "New Nerve Cells for the Adult Brain." Scientific
American. May 1999. pp.48-53.
(4) J. LeDoux, The Emotional Brain. New York, 1996. p.168.