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Perceptual learning directs auditory cortical map reorganization through top-down influences
Daniel B Polley1, Elizabeth E Steinberg, Michael M Merzenich
1W. M. Keck Foundation Center for Integrative Neuroscience, Department of Otolaryngology, University of California, San Francisco, California 94143-0732, USA. daniel.polley@vanderbilt.edu
Summary
Adult auditory cortex plasticity is shaped by top-down attention, not just sensory input. Task-specific training expands representations of attended sound features, demonstrating flexible neural maps.
Area of Science:
- Neuroscience
- Auditory Neuroscience
- Sensory Processing
Background:
- The primary sensory cortex integrates bottom-up sensory data with top-down influences like attention and reinforcement.
- Understanding how sensory maps adapt to experience is crucial for comprehending neural plasticity.
Purpose of the Study:
- To investigate whether auditory cortex map plasticity is driven by sensory input statistics or top-down, task-dependent factors.
- To examine plasticity in both the primary auditory cortex and the suprarhinal auditory field.
Main Methods:
- Rats were trained to attend to either frequency or intensity within identical auditory stimuli, isolating task demands from sensory input.
- Behavioral performance and neural map changes in auditory cortex were analyzed.
- A double-dissociation design was employed to compare plasticity across different stimulus features.
Main Results:
- Training to attend to frequency expanded the tonotopic map representation without altering intensity encoding.
- Training to attend to intensity increased nonmonotonic response profiles for target intensities but did not change tonotopic organization.
- Map plasticity correlated with perceptual learning for the trained stimulus dimension.
Conclusions:
- Auditory cortex map plasticity in adults is significantly influenced by top-down, task-specific inputs.
- This plasticity interacts with bottom-up sensory information and reinforcement learning.
- Top-down control allows for selective modification of neural representations without disrupting other sensory maps.