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Webler RD, Morales Carrasco C, Cooper SE, Chen M, Hunt CO, Hennessy S, Cao L, Lam C, Chiu A, Differding C, Todd E, Hendrickson TJ, Oathes DJ, Widge AS, Hermosillo RJ, Nelson SM, Fair DA, Lissek SM, Nahas Z. Causally Probing the Role of the Hippocampus in Fear Discrimination: A Precision Functional Mapping-Guided, Transcranial Magnetic Stimulation Study in Participants With Posttraumatic Stress Symptoms. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2024; 4:100309. [PMID: 38690260 PMCID: PMC11059300 DOI: 10.1016/j.bpsgos.2024.100309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 05/02/2024] Open
Abstract
Background Fear overgeneralization is a promising pathogenic mechanism of clinical anxiety. A dominant model posits that hippocampal pattern separation failures drive overgeneralization. Hippocampal network-targeted transcranial magnetic stimulation (HNT-TMS) has been shown to strengthen hippocampal-dependent learning/memory processes. However, no study has examined whether HNT-TMS can alter fear learning/memory. Methods Continuous theta burst stimulation was delivered to individualized left posterior parietal stimulation sites derived via seed-based connectivity, precision functional mapping, and electric field modeling methods. A vertex control site was also stimulated in a within-participant, randomized controlled design. Continuous theta burst stimulation was delivered prior to 2 visual discrimination tasks (1 fear based, 1 neutral). Multilevel models were used to model and test data. Participants were undergraduates with posttraumatic stress symptoms (final n = 25). Results Main analyses did not indicate that HNT-TMS strengthened discrimination. However, multilevel interaction analyses revealed that HNT-TMS strengthened fear discrimination in participants with lower fear sensitization (indexed by responses to a control stimulus with no similarity to the conditioned fear cue) across multiple indices (anxiety ratings: β = 0.10, 95% CI, 0.04 to 0.17, p = .001; risk ratings: β = 0.07, 95% CI, 0.00 to 0.13, p = .037). Conclusions Overgeneralization is an associative process that reflects deficient discrimination of the fear cue from similar cues. In contrast, sensitization reflects nonassociative responding unrelated to fear cue similarity. Our results suggest that HNT-TMS may selectively sharpen fear discrimination when associative response patterns, which putatively implicate the hippocampus, are more strongly engaged.
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Affiliation(s)
- Ryan D. Webler
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota
| | | | - Samuel E. Cooper
- Department of Psychiatry and Behavioral Sciences, University of Texas at Austin, Austin, Texas
| | - Mo Chen
- Department of Psychiatry, University of Minnesota, Minneapolis, Minnesota
| | - Christopher O. Hunt
- Center of Excellence for Stress and Mental Health, VA San Diego, San Diego, California
| | - Sierra Hennessy
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota
| | - Lancy Cao
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota
| | - Carol Lam
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota
| | - Allen Chiu
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota
| | - Cash Differding
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota
| | - Erin Todd
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota
| | - Timothy J. Hendrickson
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, Minnesota
- Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota
| | - Desmond J. Oathes
- Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alik S. Widge
- Department of Psychiatry, University of Minnesota, Minneapolis, Minnesota
| | - Robert J.M. Hermosillo
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, Minnesota
| | - Steven M. Nelson
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, Minnesota
| | - Damien A. Fair
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, Minnesota
| | - Shmuel M. Lissek
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota
| | - Ziad Nahas
- Department of Psychiatry, University of Minnesota, Minneapolis, Minnesota
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