Various brain areas of mammals can phyletically be traced back to
homologous structures in amphibians. The amphibian brain may thus be
regarded as a kind of "microcosm" of the highly complex primate brain,
as far as certain homologous structures, sensory functions, and assigned
ballistic (pre-planned and pre-pro- grammed) motor and behavioral
processes are concerned. A variety of fundamental operations that
underlie perception, cognition, sensorimotor transformation and its
modulation appear to proceed in primate's brain in a way understandable
in terms of basic principles which can be investigated more easily by
experiments in amphibians. We have learned that progress in the
quantitative description and evaluation of these principles can be
obtained with guidance from theory. Modeling - supported by simulation -
is a process of transforming abstract theory derived from data into
testable structures. Where empirical data are lacking or are difficult
to obtain because of structural constraints, the modeler makes
assumptions and approximations that, by themselves, are a source of
hypotheses. If a neural model is then tied to empirical data, it can be
used to predict results and hence again to become subject to
experimental tests whose resulting data in tum will lead to further
improvements of the model. By means of our present models of visuomotor
coordination and its modulation by state-dependent inputs, we are just
beginning to simulate and analyze how external information is
represented within different brain structures and how these structures
use these operations to control adaptive behavior.
