Three cortical stages of colour processing in the human brain

Area of Science:

• Neuroscience
• Cognitive Science
• Visual Perception

Background:

• Understanding the neural basis of color perception is crucial for visual neuroscience.
• Previous models of color processing have focused on early visual areas or cognitive influences, but a comprehensive pathway remains unclear.

Purpose of the Study:

• To investigate the functional magnetic resonance imaging (fMRI) identified color pathways in the human brain beyond the V4 visual area.
• To differentiate neural responses to naturally colored, unnaturally colored, and achromatic objects.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed to measure brain activity.
• Participants viewed objects presented in natural, unnatural, and achromatic colors.
• Cortical covariation analysis was performed on the observed brain activations.

Main Results:

• Both natural and unnatural colors activated pathways from V1 to V4, with some divergence from abstract color processing.
• Naturally colored objects engaged the fusiform gyrus, hippocampus, and ventrolateral frontal cortex.
• Unnaturally colored objects uniquely activated the dorsolateral frontal cortex.

Conclusions:

• Three distinct cortical stages of color processing were identified: early wavelength registration (V1/V2), automatic color constancy (V4), and object-based color perception (temporal/frontal cortex).
• The findings integrate computational and cognitive theories of color vision, accounting for both automatic processing and memory/judgment influences.
• This research provides a refined model for understanding the neural architecture of human color perception.