The Journal of Neuroscience, 2000, 20:RC70:1-4
RAPID COMMUNICATION
A Candidate Pathway for a Visual Instructional Signal to the Barn
Owl's Auditory System
Harald
Luksch,
Bärbel
Gauger, and
Hermann
Wagner
Institut für Biologie II, Rheinisch-Westfälische
Technische Hochschule Aachen, D-52074 Aachen, Germany
Many organisms use multimodal maps to generate coherent neuronal
representations that allow adequate responses to stimuli that excite
several sensory modalities. During ontogeny of these maps, one modality
typically acts as the dominant system the other modalities are aligned
to. A well studied model for the alignment of sensory maps is the
calibration of the auditory space map by the visual system in the optic
tectum of the barn owl. However, a projection from the optic tectum to
the site of plasticity in the auditory pathway that could deliver an
instructive signal has not been found so far. We have analyzed the
development of the connectivity between the bimodal (visual and
auditory) map of space in the barn owl's optic tectum and the auditory
space map in the inferior colliculus with tracing methods and
intracellular fills. Neurons in the tectal stratum griseum centrale
were found to be suited to deliver an alignment signal from the visual
midbrain to the auditory pathway. These neurons are presumably part of the efferent tectal projection pathway that mediates head saccades. The
implications of a sensory alignment signal possibly being delivered by
a (pre)motor command pathway are discussed.
Key words:
multimodal maps; optic tectum; superior colliculus; inferior colliculus; plasticity; development; premotor projections
Copyright © 2000 Society for Neuroscience 0270-6474/00/$05.00/0