So far, we have presented two arguments that memory may be encoded in single
cells: (1) long-term memory does not appear to depend on the interaction
between neurons; (2) and that single cells behave as if they learn and remember.
What, then, are the mechanisms that are available to the cell for carrying out
these functions? The most promising possibilty at this time seems to be the
synthesis of new proteins within the cell.
  Proteins are essential to all life as we know it. Certain proteins are
essential to the structure that a particular cell assumes, while other proteins,
called enzymes, control the rate of virtually every chemical reaction that
relates a cell to its environment. The resistance and conductivity of nerve
cells depends both on structural proteins and on enzymes. Thus, it is not
surprising that biochemists have found an extraordinarily high rate of protein
synthesis in nerve cells. Researchers have been able to manipulate the pattern
of protein synthesis in the brain by varying the kind and amount of stimulation
given to the animal.
  We know that cells can learn from experience to produce a particular kind of
protein. In the immune system, for example, some body cells learn to produce
a specific new protein-an antibody-to combat some foreign material such as a
transplanted organ.
   If this proves to be the case, some memory disorders may be improved with
relatively simple drugs. Nevertheless, one of the most salient characteristics
of the patient is his propensity to make contradictory statements.
