Verbal and spatial working memory in older individuals: A positron emission tomography study

Area of Science:

• Neuroscience
• Cognitive Neuroscience
• Neuroimaging

Background:

• Previous research has partially identified brain regions involved in working memory manipulation and representation.
• Understanding these regions is crucial for cognitive function, especially in aging populations.

Purpose of the Study:

• To investigate brain regions associated with manipulation and representation in working memory.
• To compare spatial and verbal working memory using neuroimaging.
• To examine these functions in middle-aged to older adults, considering hypertensive status.

Main Methods:

• A large experiment (n=89) involving middle-aged to older adults.
• Positron Emission Tomography (PET) scans using 15O-water during control, memory search, and 2-back running memory tasks.
• Tasks were adapted for verbal (letters) and spatial (positions) working memory using identical stimuli and responses.
• Regions of interest were defined based on a meta-analysis of working memory neuroimaging studies.

Main Results:

• Results largely confirmed established models of working memory organization.
• Dorsal prefrontal cortex was implicated in manipulation, and ventrolateral prefrontal cortex in maintenance.
• Dorsal and ventral pathways were involved in representation.
• Verbal and spatial working memory showed posterior lateralized representation, consistent with prior research.
• Findings were similar between older adults in this study and younger adults in previous research.

Conclusions:

• Working memory organization into distinct manipulation and maintenance areas is confirmed in older adults.
• Spatial and verbal working memory utilize distinct, lateralized neural representations.
• Cognitive functions related to working memory appear consistent across age groups in terms of brain region involvement.