Differential effects of remotely supervised transcranial direct current stimulation on recognition memory depending...

Area of Science:

• Neuroscience
• Cognitive Psychology

Background:

• Previous research indicates High Definition transcranial direct current stimulation (HD-tDCS) over the dorsolateral prefrontal cortex (DLPFC) enhances semantic memory and metamemory.
• HD-tDCS requires trained personnel, limiting its accessibility.
• Remotely supervised transcranial direct current stimulation (rs-tDCS) offers a practical alternative for tDCS application in healthy populations.

Purpose of the Study:

• To investigate if conventional rs-tDCS, less focal than HD-tDCS, yields similar effects on semantic and episodic memory and metamemory.
• To assess the impact of rs-tDCS on both semantic and episodic memory tasks, expanding beyond prior semantic memory focus.
• To evaluate the feasibility of remotely supervised tDCS in a healthy cohort.

Main Methods:

• 36 healthy participants underwent 6 weeks of either active (left or right anodal DLPFC) or sham rs-tDCS.
• Participants completed semantic memory, episodic memory, and metamemory tasks.
• The order of task completion (semantic then episodic, or episodic then semantic) was counterbalanced.

Main Results:

• No overall main effects of rs-tDCS were observed on metamemory accuracy or general memory performance.
• Significant order-dependent effects emerged: left anodal DLPFC stimulation improved semantic recognition when tasks followed episodic memory sessions.
• Conversely, right anodal DLPFC stimulation enhanced episodic recognition when tasks followed semantic memory sessions.

Conclusions:

• The effects of rs-tDCS on cognition are influenced by prior task experience.
• This study supports the feasibility of conducting tDCS research remotely with healthy participants.
• rs-tDCS shows potential for cognitive enhancement, with effects modulated by task sequencing and stimulation site.