Preface
Nearlyeveryminuteofourwakinglivesisdedicatedtointerpretingand
interacting with our surrounding environment. Individuallyoursenses give us
information about specific aspects of our environment; our sense of vision inform us of
the intensities and frequencies of light that is being reflected off surrounding objects,
our senses of touch and hearing alert us to displacements or vibrations in the matter
around us caused by movement, and our senses of smell and taste give us information
about the chemical composition of what we inhale or imbibe. Individually each sense
provides a very limited view of our surrounding, however by incorporating all of our
senses together we are provided with a robust model of our immediate environment,
allowing us to engage in complex interactions.
Primary cortical areas have been identified for all five senses; however where
and how the senses are integrated largely remains a mystery. In the traditional model
of the brain all cortical areas communicate in a feed-forward manner, with lower
cortical areas passing information to higher areas, and all areas ultimately terminating in
an undiscovered cortical area where they are integrated to form the human mind.
More recent research suggests that the brain operates in a more parallel fashion, with
cortical areas having many lateral connections and higher cortical areas frequently
passing information back to lower areas. This "parallel processing" is especially evident
in sensory cortex, where many cortical areas previously thought to be dedicated to a
single sensory modality have been shown to activate to two or more different
modalities (Ghazanfar and Schroeder 2006; Grefkes, et al. 2001), and projections