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Adaptation in macaque MT reduces perceived speed and improves speed discrimination
Bart Krekelberg1, Richard J A van Wezel, Thomas D Albright
1Systems Neurobiology Laboratories, Salk Institute for Biological Studies, La Jolla, CA 92037, USA. bart@salk.edu
Journal of Neurophysiology
|September 30, 2005
Summary
The visual system adapts to improve speed discrimination. Neural responses in the middle temporal area (MT) adjust to enhance perception of relevant environmental motion cues.
Area of Science:
- Neuroscience
- Visual Perception
- Sensory Adaptation
Background:
- The visual system exhibits adaptive changes, some beneficial (improved discrimination) and others detrimental (non-veridical perception).
- These adaptations may involve focusing on relevant environmental properties, a process studied in the middle temporal area (MT).
Purpose of the Study:
- To investigate the neural basis of adaptive changes in speed perception within the middle temporal area (MT) of macaque monkeys.
- To determine if adaptive changes in MT enhance the discrimination of visual stimuli.
Main Methods:
- Studied neural responses in the middle temporal area (MT) of macaque monkeys.
- Applied brief adaptation to moving stimuli.
- Analyzed neural response magnitude and speed tuning curves.
- Utilized ideal observer analysis.
Main Results:
- Brief adaptation to a moving stimulus reduced neural response magnitude in MT.
- Adaptation also decreased the width of speed tuning curves.
- Response changes were consistent with reduced perceived speed and improved speed discrimination.
Conclusions:
- Adaptive response changes in the middle temporal area (MT) are not merely neural fatigue.
- These changes represent an active process enhancing the discrimination of visual speed.
- Supports the hypothesis of the visual system optimizing for relevant environmental information.