Effect of eye position on saccades and neuronal responses to acoustic stimuli in the superior colliculus of the behaving cat.
Level 5 - mechanism / opinion, no new human data
Animal research / mechanistic neurophysiology study
PubMed 15190094 · doi:10.1152/jn.00453.2004
What was done
The authors tested the motor error hypothesis of visual-auditory integration in head-restrained, behaving cats trained to orient their eyes to acoustic targets. They measured behavioral sound localization accuracy and recorded single-unit neuronal responses to acoustic stimuli in the superior colliculus (SC) across different initial eye positions. They also recorded in one cat after pinna immobilization to evaluate the contribution of external ear movements.
What was found
Initial eye position did not proportionally affect sound localization accuracy. In intact cats, most single SC neurons showed auditory receptive field shifts with eye position in the direction predicted by the motor error hypothesis, accounting for approximately two-thirds of the initial eye deviation. When factoring in the average horizontal sound localization error (approximately 35% of target amplitude), the horizontal receptive field shifts matched the observed behavior. Pinna immobilization in one cat altered the pattern of modulation but did not eliminate eye-position effects.
Why it matters
This study demonstrates that superior colliculus auditory receptive fields shift with eye position to compute motor error for gaze shifts, directly matching neural coordinate transformations to behavioral localization errors.
Limits
The abstract does not state the total number of cats or individual neurons recorded. Findings are from head-restrained felines and may not fully generalize to natural free-head behavior or primates, and pinna immobilization was tested in only one animal.
Cited by
- supports Auditory signals in the superior colliculus are modulated by eye position at the time a sound is presented.