Background/objective: Anxiety disorders are highly prevalent and negatively impact daily functioning and quality of life. Transcranial direct current stimulation (tDCS) targeting the dorsolateral prefrontal cortex (dlPFC), especially in the right hemisphere impacts extinction learning; however, the underlying neural mechanisms are elusive. Therefore, we aimed to investigate the effects of cathodal tDCS stimulation to the right dlPFC on neural activity and connectivity patterns during delayed fear extinction in healthy participants.
Methods: We conducted a two-day fear conditioning and extinction procedure. On the first day, we collected fear-related self-reports, clinical questionnaires, and skin conductance responses during fear acquisition. On the second day, participants in the tDCS group ( = 16) received 20-min offline tDCS before fMRI and then completed the fear extinction session during fMRI. Participants in the control group ( = 18) skipped tDCS and directly underwent fMRI to complete the fear extinction procedure. Whole-brain searchlight classification and resting-state functional connectivity analyses were performed.
Results: Whole-brain searchlight classification during fear extinction showed higher classification accuracy of threat and safe cues in the left anterior dorsal and ventral insulae and hippocampus in the tDCS group than in the control group. Functional connectivity derived from the insula with the dlPFC, ventromedial prefrontal cortex, and inferior parietal lobule was increased after tDCS.
Conclusion: tDCS over the right dlPFC may function as a primer for information exchange among distally connected areas, thereby increasing stimulus discrimination. The current study did not include a sham group, and one participant of the control group was not randomized. Therefore, to address potential allocation bias, findings should be confirmed in the future with a fully randomized and sham controlled study.
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http://dx.doi.org/10.1016/j.ijchp.2022.100342 | DOI Listing |
Int J Clin Health Psychol
January 2025
Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany.
Fear extinction is the foundation of exposure therapy for anxiety and phobias. However, the stability of extinction memory diminishes over time, coinciding with fear recovery. To augment long-term extinction retention, the temporal distribution of extinction learning sessions is critical.
View Article and Find Full Text PDFJ Neurosci Methods
January 2025
Dept. of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy; Neuropharmacology Unit, IRCCS Santa Lucia Foundation, 00143 Rome, Italy. Electronic address:
Background: Only a small percentage of trauma-exposed subjects develop PTSD, with females being twice as likely. Most rodent models focus on males and fail to account for inter-individual variability in females.
New Method: We tested a behavioral PTSD model in female rats to distinguish between susceptible and resilient individuals.
Indian J Psychiatry
December 2024
Department of Psychiatry and Psychotherapy, University Hospital Hamburg-Eppendorf, Hamburg, Germany.
Background: Glucocorticoids increase fear extinction in preclinical and human studies. Endogenous cortisol might influence who will benefit from exposure therapy in anxiety-spectrum disorders.
Methods: To investigate the impact of cortisol levels on within-session habituation of distress - a measure of success of exposure therapy - in obsessive-compulsive disorder (OCD) fifty-one OCD patients were studied during their stressful first cognitive-behavioral exposure therapy session with response prevention.
Curr Neuropharmacol
January 2025
Centro studi e ricerche in Neuroscienze Cognitive, Dipartimento di Psicologia "Renzo Canestrari", Alma Mater Studiorum Università di Bologna, Cesena Campus, Cesena, Italy.
Post-Traumatic Stress Disorder (PTSD) is mainly characterized by dysregulated fear re- sponses, including hyperarousal and intrusive re-experiencing of traumatic memories. This work delves into the intricate interplay between abnormal fear responses, cortisol dysregulation, and the Hypothalamic-Pituitary-Adrenal (HPA) axis, elucidating their role in the manifestation of PTSD. Giv- en the persistent nature of PTSD symptoms and the limitations of conventional therapies, innovative interventions are urgently needed.
View Article and Find Full Text PDFElife
January 2025
Laboratory of Molecular Basis of Behavior, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland.
The ability to extinguish contextual fear in a changing environment is crucial for animal survival. Recent data support the role of the thalamic nucleus reuniens (RE) and its projections to the dorsal hippocampal CA1 area (RE→dCA1) in this process. However, it remains poorly understood how RE impacts dCA1 neurons during contextual fear extinction (CFE).
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