Effects of domain-specific interference on brain activation associated with verbal working memory task performance

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Human Brain Function

Background:

• Previous studies localized verbal working memory functions to specific brain regions.
• A phonological store was typically associated with the left inferior parietal cortex.
• Subvocal rehearsal mechanisms were linked to left-hemispheric speech areas.

Purpose of the Study:

• To further investigate the neural correlates of verbal working memory using functional magnetic resonance imaging (fMRI).
• To differentiate brain activation patterns during non-interfering versus interfering dual-task conditions.
• To explore the network involved in phonological storage without rehearsal.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed.
• Subjects performed verbal working memory tasks under both interfering and non-interfering dual-task conditions.
• Articulatory suppression was used to block rehearsal mechanisms.

Main Results:

• Non-interfering conditions activated established verbal working memory areas (Broca's area, left premotor cortex, left intraparietal sulcus, right cerebellum).
• Articulatory suppression (blocking rehearsal) led to no significant activation in these typical areas.
• Non-articulatory phonological maintenance showed enhanced activity in anterior prefrontal and inferior parietal regions.

Conclusions:

• Phonological storage appears to be a function of a distributed prefronto-parietal network.
• The findings challenge the notion of a single, localized parietal region for phonological storage.
• This suggests a more complex functional organization of human verbal working memory.