Double dissociation in neural correlates of visual working memory: a PET study

Area of Science:

• Neuroscience
• Cognitive Psychology

Background:

• Visual working memory (VWM) is crucial for daily tasks.
• Understanding the neural basis of VWM, particularly the distinction between spatial and object-based information processing, remains an active area of research.

Purpose of the Study:

• To investigate the neural organization of spatial versus object-based visual working memory.
• To identify distinct brain networks supporting these two types of VWM.

Main Methods:

• Positron emission tomography (PET) was used in 11 healthy human subjects.
• A conditional color-response association task was embedded within spatial and object-based VWM tasks.
• Brain activity was measured during memory retrieval and association tasks.

Main Results:

• Activation of the nucleus accumbens and anterior cingulate cortex during the associative task suggests their role in associative memory.
• The spatial VWM task activated a right-hemisphere dorsal stream network (parieto-occipital and dorsal prefrontal cortex).
• The object-based VWM task activated a left-hemisphere ventral stream network (temporo-occipital, ventral prefrontal cortex, and striatum).

Conclusions:

• The results support a domain-specific dissociation in visual working memory.
• Distinct dorsal and ventral cortical systems are involved in processing spatial and non-spatial information, respectively.