Stimulus rivalry and binocular rivalry share a common neural substrate

Area of Science:

• Neuroscience
• Visual Perception
• Cognitive Science

Background:

• Binocular rivalry involves competition for awareness between incompatible images presented to each eye.
• The neural site of this competition is debated, with theories proposing either low-level visual processing or high-level cognitive processing.

Purpose of the Study:

• To investigate the neural substrates of binocular rivalry and stimulus rivalry using frequency tagging.
• To determine if stimulus rivalry, previously thought to be high-level, shares neural signatures with low-level binocular rivalry.

Main Methods:

• Employed frequency tagging of competing stimuli during binocular rivalry and stimulus rivalry in human participants.
• Measured steady-state visually evoked potentials (SSVEPs) to identify neural competition signatures.
• Analyzed spectral power and amplitude changes at tagged frequencies in the early visual cortex.

Main Results:

• Flickering stimuli generated SSVEPs at tagged frequencies in both rivalry conditions, localized to the early visual cortex.
• Dynamic signatures of neural competition, tracked via amplitude changes, colocalized in occipital regions for both rivalry types.
• Specific regions identified include the occipital pole and the middle temporal gyrus (hMT+/V5).

Conclusions:

• Neural competition in stimulus rivalry, contrary to hypothesis, appears to occur at low visual processing levels, similar to binocular rivalry.
• Findings suggest that both binocular and stimulus rivalry may share neural substrates in early visual areas, supporting a low-level interpretation.