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Sensorimotor integration in the primate superior colliculus. I. Motor convergence.
Journal of Neurophysiology
|January 1, 1987
Summary
This study shows that brain cells in the superior colliculus (SC) help control eye movements to both sounds and sights. This suggests a shared pathway for sensory-to-motor transformations, integrating auditory and visual information for orienting responses.
Area of Science:
- Neuroscience
- Sensory processing
- Motor control
Background:
- Orienting movements to auditory and visual stimuli involve complex sensory-to-motor transformations.
- The brain must integrate sensory information encoded in different coordinate systems for effective orienting responses.
Purpose of the Study:
- To investigate whether neurons in the superior colliculus (SC) involved in visual saccades also activate for auditory targets.
- To determine if auditory and visual signals converge onto common motor pathways in the SC.
Main Methods:
- Trained monkeys performed saccadic eye movements towards auditory and visual targets.
- Neuronal activity of visual-motor (V-M) and saccade-related burst (SRB) cells in the SC was recorded.
- Spike activity patterns were compared between auditory and visual target trials.
Main Results:
- Most V-M cells responded only to visual stimuli, not auditory stimuli from the same location.
- However, a significant majority (79%) of V-M and SRB cells exhibited motor bursts before saccades to either auditory or visual targets.
- Saccades to auditory targets were generally slower than those to visual targets.
Conclusions:
- Auditory and visual signals are transformed to share a common efferent pathway for saccadic eye movements, originating from different coordinate systems.
- The number of active SC neurons may influence saccadic eye movement velocity, with fewer neurons firing for auditory targets.