Weighing the evidence for a dorsal processing bias under continuous flash suppression

Area of Science:

• Cognitive Neuroscience
• Visual Perception
• Neuroscience

Background:

• Continuous flash suppression (CFS) is a technique used to render visual stimuli invisible, facilitating the study of unconscious visual processing.
• A popular hypothesis suggests CFS preferentially preserves dorsal visual stream functions (vision-for-action) while suppressing ventral stream functions (vision-for-perception), aligning with the dual-stream model.

Purpose of the Study:

• To review neuroimaging and behavioral studies investigating the proposed CFS-specific dorsal processing bias.
• To evaluate the validity of the dorsal processing bias hypothesis in the context of unconscious visual processing research using CFS.

Main Methods:

• Systematic review and synthesis of existing neuroimaging and behavioral studies employing continuous flash suppression (CFS).
• Analysis of studies that either directly test or rely on the assumption of a dorsal processing bias under CFS.

Main Results:

• Evidence was found supporting both the preservation of ventral stream processing and the lack of dorsal stream processing under CFS conditions.
• The reviewed literature presents conflicting findings regarding the selective preservation of dorsal stream functions during CFS.

Conclusions:

• A universal dorsal processing bias under continuous flash suppression (CFS) cannot be assumed based on current evidence.
• Further research is needed to reconcile divergent findings by examining methodological differences in CFS paradigms and their impact on visual stream processing.