Working memory and conscious perception are often thought to rely on the same brain mechanisms, but recent evidence suggests non-conscious working memory exists. Using visual masking and magnetoencephalography in a spatial delayed-response task, participants reported the location of a subjectively unseen target above chance after a long delay. Conscious perception and conscious working memory showed sustained alpha/beta desynchronization over frontal cortex and decodable target location in posterior sensors. During non-conscious working memory, these signals vanished, contradicting models equating working memory with sustained neural firing. The findings support 'activity-silent' working memory, where slowly decaying synaptic changes allow cell assemblies to go dormant during the delay yet be retrieved above chance after seconds.
Conscious perception may not be a discrete event but a dynamic process in which a stimulus is continuously recoded to fit an ongoing stream of other perceived stimuli. This hypothesis can reconcile inconsistent findings on the timing of neural correlates of consciousness and makes testable predictions. The updating process is governed by context, stimulus saliency, and the observer's goal. The framework challenges the typical distinction between conscious and unconscious information processing.
The psychological refractory period (PRP) and attentional blink (AB) are two well-known phenomena that limit the ability to process two successive tasks or stimuli. A neuromimetic model proposed they might share a common bottleneck—a serial stage where stimuli gain access to consciousness. Using magneto-encephalography (MEG) in a cross-modal paradigm with an auditory first target and a visual second target, the authors observed both PRP (delayed processing) and AB (missed detection) on different trials with identical stimuli. Brain recordings showed identical early sensory processing in visual cortices for both trial types, but later frontal activations (>350 ms) were delayed in PRP trials and absent in blinked trials. The results indicate that both phenomena arise from the same cortical stages and are distinguished by trial-by-trial fluctuations in task processing.