How do low-level sensory processes change through perceptual learning?

Perceptual learning improves the ability of sensory systems to respond to stimuli through experience and practice. Contrary to earlier assumptions that low-level sensory processes were immutable after early development, research has shown that these systems are highly plastic and can be reshaped by experience.1

Low-level sensory processes change through several specific neural mechanisms:

• Increased Neural Representation: The number of neurons responding to a stimulus in a given brain region increases, which enhances the statistical reliability of sensory decisions. This has been observed in the somatosensory, auditory, and motor cortices.1
• Sharpening of Tuning Functions: Neurons become more selective, narrowing the range of stimulus attributes to which they respond. This reduces the overlap between neighboring neurons' responses, effectively increasing the distance between them along the trained stimulus dimension.1
• Changes in Response Timing: Practice can increase the synchronicity of firing across ensembles of neurons, particularly in tasks involving temporal characteristics or, in some cases, non-temporally varying stimuli like odors.1

These changes reflect the brain's ability to optimize how it encodes and represents sensory information to improve performance in specific tasks.1