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Updated: Jun 25, 2026
09:42
Stimulus-specific Cortical Visual Evoked Potential Morphological Patterns
Published on: May 12, 2019
Top-down activation of shape-specific population codes in visual cortex during mental imagery
Mark Stokes1, Russell Thompson, Rhodri Cusack
1Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, United Kingdom. mark.stokes@sjc.ox.ac.uk
Summary
Visual imagery activates the same neural representations as actual sight. This research shows top-down mechanisms precisely target specific neural codes in the visual cortex for mental images.
Area of Science:
- Neuroscience
- Cognitive Science
- Visual Perception
Background:
- Visual imagery involves top-down activation of the visual cortex.
- Neural patterns differ based on the content of visual imagery (e.g., faces vs. places).
- The precise neural coding during imagery, similar to perception, is not fully understood.
Purpose of the Study:
- To investigate if top-down mechanisms can selectively activate perceptual representations.
- To determine if internally generated visual activity mirrors fine-scale population coding in stimulus-driven perception.
- To explore the precision of top-down activation in perceptual representations.
Main Methods:
- Utilized neural pattern classification to analyze brain activity.
- Identified activation patterns associated with the imagery of distinct letter stimuli.
- Examined neural populations within high-level visual cortex, including the lateral occipital complex.
Main Results:
- Imagery of letters activated the same neural representations as perceiving those letters.
- Pattern analysis confirmed that top-down activation precisely targets specific neural population codes.
- Findings were consistent within high-level visual cortex areas.
Conclusions:
- Visual imagery is mediated by top-down activation of specific neural population codes.
- These codes are functionally distinct yet spatially overlapping for high-level visual representations.
- Internal visual activity precisely matches the neural representations used in perception.
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