No evidence for mnemonic modulation of interocularly suppressed visual input

Area of Science:

• Cognitive Neuroscience
• Perception and Memory

Background:

• Visual working memory (VWM) retains visual information for goal-directed behavior during concurrent processing of new input.
• VWM content influences visual perception, speeding detection of matching suppressed stimuli, but the timing of this influence (pre- or post-conscious access) is debated.

Purpose of the Study:

• To investigate if VWM content modulates neural responses to visual input that remains suppressed from consciousness.
• To determine whether mnemonic influences on perception occur before or after conscious access.

Main Methods:

• fMRI was used to measure neural responses to interocularly suppressed stimuli in 20 participants.
• A delayed match-to-sample task involved memorizing shapes, followed by presentation of cued or uncued shape probes during retention.
• Regions of interest prone to modulation and directional Bayesian tests were employed to maximize detection sensitivity.

Main Results:

• No evidence was found for VWM content modulating the neural response to suppressed visual probes.
• Robust evidence for the absence of modulation was obtained using liberal analysis approaches.
• Behavioral control confirmed faster detection of memory-matching probes, validating the stimuli.

Conclusions:

• VWM content does not appear to modulate neural processing of visual input while it is suppressed from consciousness.
• The findings suggest that VWM impacts visual input processing only after conscious suppression is largely resolved.
• This indicates mnemonic influences on perception occur later in the processing stream, post-conscious access.