No Selective Attentional Shift despite Prefrontal Activation during a Working-Memory Task with Unconscious Stimuli

Area of Science:

• Cognitive Neuroscience
• Psychology

Background:

• Successful working memory relies on prioritizing relevant information and controlling attention.
• Attentional control is crucial for filtering distractions and focusing on task-relevant stimuli.

Purpose of the Study:

• To investigate attentional control during unconscious working memory.
• To determine if prestimulus cues can guide attention for unconsciously processed information.
• To examine neural correlates of attentional control under conscious versus unconscious working memory conditions.

Main Methods:

• A delayed match-to-sample task was used with unconsciously presented stimuli.
• Prestimulus cues indicated target side, but cue validity was manipulated (valid, invalid).
• Functional magnetic resonance imaging (fMRI) measured brain activity (BOLD signal change).

Main Results:

• Participants performed better with valid cues for unconscious trials, suggesting limited reorienting ability with invalid cues.
• Medial and lateral prefrontal cortex showed significant activity for unconscious stimuli, but not modulated by cue validity.
• Parietal regions did not show significant activation for unconscious stimuli, regardless of cue validity.

Conclusions:

• While cognitive control regions activate for unconscious stimuli, adaptive selective attention is not evident.
• Attentional deployment differs significantly between conscious and unconscious working memory.
• The brain's ability to control attention appears to be constrained by conscious awareness.