Transcranial direct current stimulation modulates spatial memory in cognitively intact adults.

Area of Science:

• Neuroscience
• Cognitive Psychology

Background:

• Object location memory involves distinct coordinate and categorical processing systems.
• Coordinate processing is linked to the right posterior parietal cortex (PPC), while categorical processing is associated with the left PPC.

Purpose of the Study:

• To investigate the causal roles of the left and right PPC in spatial memory using transcranial direct current stimulation (tDCS).
• To differentiate the effects of tDCS on coordinate versus categorical spatial memory during encoding and recall.

Main Methods:

• Twelve healthy participants received tDCS with anodal/cathodal stimulation targeting the right and left PPC (R+L- and R-L+ montages) or sham stimulation.
• Participants completed the Object Location Touchscreen Task (OLTT) to assess coordinate and categorical memory during and after stimulation.

Main Results:

• Participants showed improved accuracy in coordinate memory recall following left PPC inhibitory stimulation (R-L+ montage) compared to right PPC inhibitory stimulation (R+L-).
• Categorical memory performance was not significantly affected by either stimulation condition.

Conclusions:

• Findings suggest that left PPC inhibition may enhance coordinate spatial memory, potentially through increased mental imagery or reduced neural noise in the right PPC.
• Further research with larger sample sizes is needed to confirm these effects and elucidate the underlying mechanisms.