A Review of Memory Intervention With Noninvasive Brain Stimulation in Post-traumatic Stress Disorder and Substance Use Disorder

Abstract

Memory is an essential function for accumulating experience and promoting individual survival. However, post-traumatic stress disorder (PTSD) and substance use disorders (SUD) are characterized by maladaptive memory, which is unfavorable for individual survival. Therefore, one idea to develop treatment for PTSD and SUD, psychiatric disorders characterized by excessive fear memories or addiction memories, is to extinguish or update maladaptive memories. Memory intervention is based on the fact that memory is an ongoing process that allows updating and integrating information. The reactivation of memory may induce memory retrieval and reconsolidation, rendering a time window with increase plasticity of the neural circuits underlying the pieces of the retrieved memory. Interventions within this critical time window may have better therapeutic effect compared to interventions outside the time window. Noninvasive brain stimulation (NIBS), as a noninvasive physical therapy, has been viewed a candidate for maladaptive memory intervention. NIBS can be applied with specific stimulation parameters (anatomical targets, frequency, polarity, behavioral state, etc.) to achieve varied stimulation effects. NIBS can alter cortical excitability and modulate neuroplasticity in the targeted region or other brain regions connected to the targeted region. When NIBS is applied to memory related brain areas, it may disrupt or alter memory-related neural circuit activity thereby changing memory related emotion or behavioral performance. In this review, we summarize recent studies using NIBS (transcranial magnetic stimulation, TMS, and transcranial direct current stimulation, tDCS, mainly) interventions for trauma-or substance-use-related memory during memory reconsolidation, along with theoretical basis from brain imaging or preclinical evidence from rodent studies. There are two basic ideas for NIBS interventions in maladaptive memories, to enhance activity in extinction-related neural circuit by TMS or tDCS, or to suppress activity in brain areas related to maladaptive emotional or motivational processing during memory reconsolidation. Both ideas got supporting results from research in the laboratory, while there has been no convincing evidence from clinical application yet. This review summarizes research evidence about the application of NIBS in fear and addiction memory intervention and hopes to contribute to breed insights for the development of NIBS treatment for memory-related psychiatric disorders targeting reconsolidation process.