Processing of Targets and Non-targets in Verbal Working Memory

Area of Science:

• Cognitive Neuroscience
• Neuroimaging

Background:

• Verbal working memory (WM) involves retaining and manipulating information.
• Distinguishing between target and non-target stimuli may modulate brain activity during WM tasks.

Purpose of the Study:

• To investigate how defining a stimulus as a target impacts brain activation during a verbal WM task using fMRI.
• To examine hemispheric and fronto-parietal differences in brain activity between target and non-target stimuli.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was employed on 17 healthy participants.
• Participants performed a Sternberg task with a three-consonant memory set.
• Region of interest analysis and MANOVA were used to compare brain activity for targets versus non-targets.

Main Results:

• A significant hemisphere by fronto-parietal interaction was observed.
• Targets elicited greater activity in right frontal regions compared to non-targets.
• Increased activity for targets was found in the lateral anterior parietal regions, but not the medial posterior part.

Conclusions:

• Target identification in verbal WM tasks selectively enhances activity in right frontal brain regions.
• Hemispheric differentiation exists, with the right frontal cortex specializing in target processing.
• The left frontal cortex and medial posterior parietal regions appear to process information irrespective of target status.