A Systematic Review on the Effect of Transcranial Direct Current and Magnetic Stimulation on Fear Memory and Extinction - PubMed (original) (raw)

A Systematic Review on the Effect of Transcranial Direct Current and Magnetic Stimulation on Fear Memory and Extinction

Vuk Marković et al. Front Hum Neurosci. 2021.

Abstract

Anxiety disorders are among the most prevalent mental disorders. Present treatments such as cognitive behavior therapy and pharmacological treatments show only moderate success, which emphasizes the importance for the development of new treatment protocols. Non-invasive brain stimulation methods such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) have been probed as therapeutic option for anxiety disorders in recent years. Mechanistic information about their mode of action, and most efficient protocols is however limited. Here the fear extinction model can serve as a model of exposure therapies for studying therapeutic mechanisms, and development of appropriate intervention protocols. We systematically reviewed 30 research articles that investigated the impact of rTMS and tDCS on fear memory and extinction in animal models and humans, in clinical and healthy populations. The results of these studies suggest that tDCS and rTMS can be efficient methods to modulate fear memory and extinction. Furthermore, excitability-enhancing stimulation applied over the vmPFC showed the strongest potential to enhance fear extinction. We further discuss factors that determine the efficacy of rTMS and tDCS in the context of the fear extinction model and provide future directions to optimize parameters and protocols of stimulation for research and treatment.

Keywords: dorsolateral prefrontal cortex; fear extinction; fear memory; non-invasive brain stimulation; repetitive transcranial magnetic stimulation; ventromedial prefrontal cortex.

Copyright © 2021 Marković, Vicario, Yavari, Salehinejad and Nitsche.

PubMed Disclaimer

Conflict of interest statement

MN is a member of the Scientific Advisory Boards of Neuroelectrics and NeuroDevice. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1

Figure 1

PRISMA flow diagram selected for qualitative analysis of the respective studies.

Figure 2

Figure 2

Model on how NIBS is thought to influence fear memory formation. Inhibitory NIBS of left dlPFC interferes with fear memory consolidation by downregulating the activity of the amygdala which, in turn, downregulates the hippocampus, which is responsible for memory consolidation, and ACC/insula, which are involved in the expression of fear responses. Excitatory NIBS of the right dlPFC boosts fear memory consolidation by upregulating the activity of amygdala, which, in turn, upregulates the activity of hippocampus and ACC/Insula.

Figure 3

Figure 3

Model on how NIBS is thought to influence fear extinction memory. Excitatory NIBS over the left vmPFC downregulates the output of the central nucleus of the amygdala via activation of the intercalated nucleus, which in turn upregulates hippocampus, responsible for memory consolidation.

Figure 4

Figure 4

Complex and mutual relationships between various factors mediating the effects of NIBS methods on fear and extinction memory. _Type of NIBS_- refers to which NIBS method is applied, e.g., rTMS, tDCS; Hemispheric lateralization refers to whether stimulation is dominantly applied over the left or right hemisphere; Polarity/frequency refers to whether anodal or cathodal tDCS is applied, or low or high frequency rTMS; Duration refers to duration of the applied stimulation; Area- refers to which area is intended to be targeted for the stimulation; Intensity refers to the intensity of applied stimulation; Timing refers to whether stimulation is applied before, simultaneously or after the extinction/exposure; Task- refers to specifics of the fear conditioning/extinction protocol (e.g., reinforcement rate, modality of the US, using CS+ reminders).

References

    1. Abbasi S., Nasehi M., Lichaei H. R. S., Zarrindast M. R. (2017). Effects of left prefrontal transcranial direct current stimulation on the acquisition of contextual and cued fear memory. Iran. J. Basic Med. Sci. 20:623. -PMC -PubMed
    1. Abend R., Jalon I., Gurevitch G., Sar-El R., Shechner T., Pine D. S., et al. (2016). Modulation of fear extinction processes using transcranial electrical stimulation. Transl. Psychiatry 6, e913–e913. 10.1038/tp.2016.197 -DOI -PMC -PubMed
    1. Abend R., van't Wout M. (2018). Commentary: augmentation of fear extinction by Transcranial Direct Current Stimulation (tDCS). Front. Behav. Neurosci. 12:121. 10.3389/fnbeh.2018.00121 -DOI -PMC -PubMed
    1. Abramowitz J. S., Deacon B. J., Olatunji B. O., Wheaton M. G., Berman N. C., Losardo D., et al. (2010). Assessment of obsessive-compulsive symptom dimensions: development and evaluation of the dimensional obsessive-compulsive scale. Psychol. Assess 22:180. 10.1037/a0018260 -DOI -PubMed
    1. Adams J. T., Badran B. W., George M. S. (2014). Integration of cortical brain stimulation and exposure and response prevention for obsessive-compulsive disorder (OCD). Brain Stimul. 7, 764–765. 10.1016/j.brs.2014.06.010 -DOI -PubMed

Publication types

LinkOut - more resources