Distribution of auditory motion-direction sensitive neurons in the barn owl's midbrain.
Barn owls have neurons sensitive to acoustic motion-direction in the midbrain. We report here that acoustic motion-direction sensitive neurons with receptive-field centres in frontal auditory space are not randomly distributed. In the inferior colliculus and optic tectum in the left (right) brain, the responses of about two-thirds of the motion-direction sensitive neurons were sensitive to clockwise (counter-clockwise) motion. The midbrain contains maps of auditory space that represent about 15 degrees of ipsilateral and all of contralateral space. Since a similar bias in motion-direction sensitivity was observed for neurons with receptive-field centres in ipsilateral as well as for neurons with receptive fields centres in contralateral auditory space, the brain side at which a motion-direction sensitive neuron was recorded was a more important predictor for the preferred direction of a cell than the spatial direction of the centre of the receptive field. Within one dorso-ventral electrode pass motion-direction sensitivity typically stayed constant suggesting a clustered or even a columnar-like organization. We hypothesize from these distributions that the right brain is important for orientating movements to the left hemisphere and vice versa.
Wagner
H
H
Max-Planck-Institute for Biological Cybernetics, Tuebingen, Germany. wagner@bio2.rwth-aachen.de
von Campenhausen
M
M
D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D008636:Mesencephalon / Q000033:anatomy & histology / Q000502:physiology*; D009039:Motion Perception / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology*; D020305:Strigiformes / Q000502:physiology*