Perceptual training selectively strengthens top-down signaling to sensory cortex

Area of Science:

• Neuroscience
• Cognitive Science
• Auditory Perception

Background:

• Sensory cortical neurons adapt responses to behaviorally relevant stimuli.
• Top-down signals from frontal cortex are hypothesized to mediate these sensory changes.
• Strengthening of these top-down signals during perceptual learning remains untested.

Purpose of the Study:

• Investigate orbitofrontal cortex (OFC) neuronal activity during auditory perceptual learning.
• Determine if learning-related neural changes are transmitted to sensory cortex.
• Test the hypothesis that top-down signals strengthen during learning.

Main Methods:

• Recorded neuronal activity in the OFC of animals undergoing auditory perceptual learning.
• Analyzed OFC neuronal encoding of trial outcome and stimulus features.
• Assessed the transmission of learning-related changes to auditory and visual cortex.

Main Results:

• OFC neurons encode both trial outcome and stimulus information.
• Signal strength and sensitivity in OFC neurons increased with learning of weaker amplitude modulations.
• Learning-related neural changes were transmitted to auditory cortex, but not visual cortex.

Conclusions:

• OFC neuronal activity is modified during auditory perceptual learning.
• Perceptual learning selectively strengthens task-relevant frontal-to-sensory cortical circuits.
• Provides direct evidence for modification of top-down cortical networks during perceptual learning.