Transcranial direct current stimulation impairs updating of avoidance-based associative learning

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychotherapy Research

Background:

• Exposure-based psychotherapies utilize corrective associative learning to treat anxiety disorders.
• This learning, however, is often context-bound and poorly generalizes.
• The prefrontal cortex is involved in context-guided behavior and may enhance safety learning generalization.

Purpose of the Study:

• To investigate the causal role of the left prefrontal cortex in updating context-bound associations.
• To determine if prefrontal cortex inhibition affects generalization of safety learning to new contexts.

Main Methods:

• Two experiments used cathodal transcranial direct current stimulation (tDCS) or sham stimulation over the left prefrontal cortex.
• Participants underwent reversal learning of associations in the same or different context.
• Generalization was assessed by preference for stimuli in a novel context.

Main Results:

• tDCS impaired association reversal irrespective of context in one experiment.
• Sham stimulation showed higher learning rates when reversal occurred in a different context compared to active tDCS.
• Active tDCS was linked to preferring originally disadvantageous stimuli after reversal in a new context in one experiment.

Conclusions:

• The left prefrontal cortex plays a causal role in updating avoidance-based associations.
• Non-invasive brain stimulation may improve flexible updating of learned associations for therapeutic benefit.