Transcranial direct current stimulation may modulate extinction memory in posttraumatic stress disorder

Abstract

BackgroundAbnormalities in fear extinction and recall are core components of posttraumatic stress disorder (PTSD). Data from animal and human studies point to a role of the ventromedial prefrontal cortex (vmPFC) in extinction learning and subsequent retention of extinction memories. Given the increasing interest in developing noninvasive brain stimulation protocols for psychopathology treatment, we piloted whether transcranial direct current stimulation (tDCS) during extinction learning, vs. during consolidation of extinction learning, might improve extinction recall in veterans with warzone‐related PTSD.MethodsTwenty‐eight veterans with PTSD completed a 2‐day Pavlovian fear conditioning, extinction, and recall paradigm. Participants received one 10‐min session of 2 mA anodal tDCS over AF3, intended to target the vmPFC. Fourteen received tDCS that started simultaneously with extinction learning onset, and the remaining 14 participants received tDCS during extinction consolidation. Normalized skin conductance reactivity (SCR) was the primary outcome measure. Linear mixed effects models were used to test for effects of tDCS on late extinction and early extinction recall 24 hr later.ResultsDuring early recall, veterans who received tDCS during extinction consolidation showed slightly lower SCR in response to previously extinguished stimuli as compared to veterans who received tDCS simultaneous with extinction learning (p = .08), generating a medium effect size (Cohen's d = .38). There was no significant effect of tDCS on SCR during late extinction.ConclusionsThese preliminary findings suggest that testing the effects of tDCS during consolidation of fear extinction may have promise as a way of enhancing extinction recall.

Brain Structural Covariance Network Topology in Remitted Posttraumatic Stress Disorder

“…These interpretations will require testing in future studies on the role of the frontal pole in remitted and current PTSD and could be explored as a potential target for therapeutic intervention. A recent study using transcranial direct current stimulation (tDCS) has already targeted ventromedial prefrontal cortex for the treatment of PTSD ( 62 ). Future clinical intervention on PTSD may utilize interventions including tDCS and deep brain stimulation targeting frontal pole.…”

Augmentation of Fear Extinction by Transcranial Direct Current Stimulation (tDCS)

“…To close the circle, these neurons showed also strong bidirectional connections with the vmPFC. Based on these data we aimed—like many other researchers, who tried to modulate extinction processes via brain stimulation—to activate the vmPFC (Guhn et al, 2014 ; Abend et al, 2016 ; Van't Wout et al, 2016 , 2017 ; Raij et al, 2017 ). On the neurobiological level, especially the neurotransmission of dopamine seems to be a crucial factor for functioning extinction (Hikind and Maroun, 2008 ; Raczka et al, 2011 ; Abraham et al, 2016 ).…”

“…In 2016 she found a slight improvement of late extinction learning in healthy participants when the stimulation took place during early extinction learning, but this effect could not be distinguished from anxiolytic tDCS-aftereffects with certainty (Van't Wout et al, 2016 ). In 2017 she stimulated PTSD patients during or after extinction learning and found only a trend-significant improvement of extinction recall in the after extinction learning condition (Van't Wout et al, 2017 ). Both authors aimed to stimulate the vmPFC but used different electrode positions to do so.…”

Nicht invasive Hirnstimulation und Furchtextinktion

“…In der vierten Studie von van t' Wout et al [18] durchliefen Patienten mit einer posttraumatischen Belastungsstörung (PTBS) ein Zwei-Tages-Protokoll. Am ersten Tag erfolgten eine Furchtkonditionierung und Extinktion und am zweiten Tag eine erneute Extinktion, um das Extinktionsgedächtnis zu messen.…”

“…Für die Methode tDCS zeigen erste Studien positive Effekte, allerdings müssen die Ergebnisse noch weiter repliziert und ausgeweitet werden. Die Arbeiten von van 't Wout et al [15,18] legen nahe, dass die in diesen Arbeiten verwendete Anordnung der Stimulationselektroden nicht die Extinktionsleistung an sich moduliert, sondern wahrscheinlicher die Konsolidierung des Extinktionsgedächtnisses. Die Autoren haben in einer Machbarkeitsstudie gezeigt, dass die Kombination von tDCS mit einer Expositionstherapie in virtueller Realität möglich ist [24], sodass in der Zukunft sicherlich einige neue randomisierte und kontrollierte Therapiestudien mit diesem Verfahren publiziert werden.…”