HOW OUR EYES AFFECT OUR EARS: VISUAL INTRUSIONS INTO THE DOMAIN OF
HEARING J.M.Groh*1; Y.E.Cohen1; T.R.Stanford2; E.I.Knudsen3
1. Dept. of Psychological and Brain Sciences, Dartmouth College,
Hanover, NH, USA; 2. Dept. of Neurobiology and Anatomy, Wake Forest
University, Winston-Salem, NC, USA; 3. Dept. of Neurobiology, Stanford
University, Stanford, CA, USA

Historically, the brain's sensory pathways have been viewed as
separate and distinct from one another. Recent findings in the domain
of visual, auditory, and motor processing challenge this premise, and
suggest that communication between the sensory systems begins at an
earlier point in sensory pathways and is more pervasive than has
previously been thought. This symposium brings together four studies
concerning visual and auditory interactions in a variety of species
and brain areas, each of which presents an unexpected finding in the
domain of multisensory processing. Auditory signals in the ascending
auditory pathway of primates are dependent on where the eyes are
looking (Groh). Reaching movements to sounds are encoded in an
eye-centered frame of reference in primate parietal cortex, a
coordinate system that is neither anchored to the sensory stimulus nor
to the motor response (Cohen). A structure long implicated in
multisensory integration, the cat superior colliculus, combines visual
and auditory signals in a very nearly linear fashion, contrary to
prior expectations (Stanford). Visually-induced changes in auditory
processing occur in an area of the auditory pathway of barn owls that
does not itself have visual responses (Knudsen). These findings
suggest that the brain's sensory pathways begin communicating with one
another very early on, and do so in surprising ways.