Left DLPFC involvement in verbal working memory in ageing: A cTBS-ERP study

Area of Science:

• Neuroscience
• Cognitive Psychology
• Gerontology

Background:

• Aging is linked to cognitive decline, especially in working memory (WM).
• Dorsolateral prefrontal cortex (DLPFC) functioning is crucial for WM.
• The causal role of the left DLPFC in older adults' WM needs further investigation.

Purpose of the Study:

• To investigate the causal role of the left DLPFC in verbal and visuospatial WM performance in healthy older adults.
• To examine the effects of disrupting left DLPFC activity using continuous Theta Burst Stimulation (cTBS).
• To correlate behavioural and electroencephalography (EEG) measures with stimulation conditions.

Main Methods:

• Twenty healthy older adults participated.
• Participants performed verbal and visuospatial N-back tasks under baseline, vertex, and left DLPFC cTBS conditions.
• Behavioural data and EEG recordings were collected.

Main Results:

• Vertex stimulation showed learning improvements in verbal WM.
• Left DLPFC stimulation yielded inconclusive behavioural results for verbal WM but suggested potential learning effects in visuospatial WM.
• EEG revealed latency modulations in event-related potentials (ERPs), particularly P200 and P300, linked to attentional processing and accuracy in verbal WM.

Conclusions:

• Preliminary evidence supports the left DLPFC's involvement in verbal WM in older adults.
• The left DLPFC may be critical for the temporal coordination of attention and cognitive control processes in aging WM.
• Further research is needed to clarify the role of DLPFC in visuospatial WM and aging.