Identification of Reliable Target Brain Regions for Enhancing Object-Location Memory by Brain Stimulation

Area of Science:

• Neuroscience
• Cognitive Psychology

Background:

• Object-location memory (OLM) is crucial for spatial navigation and is often impaired in aging and neurodegenerative conditions.
• Transcranial direct current stimulation (tDCS) shows potential for OLM enhancement, but results vary, necessitating identification of optimal stimulation targets.

Purpose of the Study:

• Identify key brain regions involved in OLM for future tDCS targeting.
• Assess the test-retest reliability (TRR) of behavioral and functional magnetic resonance imaging (fMRI) measures for OLM.

Main Methods:

• Twenty healthy young adults underwent two fMRI sessions performing a validated OLM task with sham tDCS.
• Participants learned object-location associations across feedback-based learning stages.
• TRR was evaluated using intraclass correlation coefficients (ICCs) for behavioral and fMRI data.

Main Results:

• Behavioral performance improved significantly in accuracy and response speed across learning stages.
• fMRI revealed right-lateralized activation in regions including the hippocampus, fusiform gyrus, precuneus, and lateral temporo-occipital areas.
• Both behavioral (accuracy ICC=0.801, reaction time ICC=0.705) and fMRI measures demonstrated good to excellent TRR.

Conclusions:

• The OLM paradigm is validated for assessing brain stimulation effects.
• Identified cortical regions serve as promising targets for future tDCS interventions.
• High reliability of behavioral and neural measures supports the protocol's use in crossover designs.