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Anger JT, Case LK, Baranowski AP, Berger A, Craft RM, Damitz LA, Gabriel R, Harrison T, Kaptein K, Lee S, Murphy AZ, Said E, Smith SA, Thomas DA, Valdés Hernández MDC, Trasvina V, Wesselmann U, Yaksh TL. Pain mechanisms in the transgender individual: a review. Front Pain Res (Lausanne) 2024; 5:1241015. [PMID: 38601924 PMCID: PMC11004280 DOI: 10.3389/fpain.2024.1241015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 01/25/2024] [Indexed: 04/12/2024] Open
Abstract
Specific Aim Provide an overview of the literature addressing major areas pertinent to pain in transgender persons and to identify areas of primary relevance for future research. Methods A team of scholars that have previously published on different areas of related research met periodically though zoom conferencing between April 2021 and February 2023 to discuss relevant literature with the goal of providing an overview on the incidence, phenotype, and mechanisms of pain in transgender patients. Review sections were written after gathering information from systematic literature searches of published or publicly available electronic literature to be compiled for publication as part of a topical series on gender and pain in the Frontiers in Pain Research. Results While transgender individuals represent a significant and increasingly visible component of the population, many researchers and clinicians are not well informed about the diversity in gender identity, physiology, hormonal status, and gender-affirming medical procedures utilized by transgender and other gender diverse patients. Transgender and cisgender people present with many of the same medical concerns, but research and treatment of these medical needs must reflect an appreciation of how differences in sex, gender, gender-affirming medical procedures, and minoritized status impact pain. Conclusions While significant advances have occurred in our appreciation of pain, the review indicates the need to support more targeted research on treatment and prevention of pain in transgender individuals. This is particularly relevant both for gender-affirming medical interventions and related medical care. Of particular importance is the need for large long-term follow-up studies to ascertain best practices for such procedures. A multi-disciplinary approach with personalized interventions is of particular importance to move forward.
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Affiliation(s)
- Jennifer T. Anger
- Department of Urology, University of California San Diego, San Diego, CA, United States
| | - Laura K. Case
- Department of Anesthesiology, University of California San Diego, San Diego, CA, United States
| | - Andrew P. Baranowski
- Pelvic Pain Medicine and Neuromodulation, University College Hospital Foundation Trust, University College London, London, United Kingdom
| | - Ardin Berger
- Anesthesiology, Perioperative and Pain Medicine, Stanford University, Stanford, CA, United States
| | - Rebecca M. Craft
- Department of Psychology, Washington State University, Pullman, WA, United States
| | - Lyn Ann Damitz
- Division of Plastic and Reconstructive Surgery, University of North Carolina, Chapel Hill, NC, United States
| | - Rodney Gabriel
- Division of Regional Anesthesia, University of California San Diego, San Diego, CA, United States
| | - Tracy Harrison
- Department of OB/GYN & Reproductive Sciences, University of California San Diego, San Diego, CA, United States
| | - Kirsten Kaptein
- Division of Plastic Surgery, University of California San Diego, San Diego, CA, United States
| | - Sanghee Lee
- Department of Urology, University of California San Diego, San Diego, CA, United States
| | - Anne Z. Murphy
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Engy Said
- Division of Regional Anesthesia, University of California San Diego, San Diego, CA, United States
| | - Stacey Abigail Smith
- Division of Infection Disease, The Hope Clinic of Emory University, Atlanta, GA, United States
| | - David A. Thomas
- Office of Research on Women's Health, National Institutes of Health, Bethesda, MD, United States
| | - Maria del C. Valdés Hernández
- Department of Neuroimaging Sciences, Center for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Victor Trasvina
- Department of Urology, University of California San Diego, San Diego, CA, United States
| | - Ursula Wesselmann
- Departments of Anesthesiology and Perioperative Medicine/Division of Pain Medicine, Neurology and Psychology, and Consortium for Neuroengineering and Brain-Computer Interfaces, The University of Alabama at Birmingham, Birmingham, AL, United States
| | - Tony L. Yaksh
- Department of Anesthesiology, University of California San Diego, San Diego, CA, United States
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Baumgartner JN, Haupt MR, Case LK. Chronic pain patients low in social connectedness report higher pain and need deeper pressure for pain relief. Emotion 2023; 23:2156-2168. [PMID: 36996174 PMCID: PMC10544689 DOI: 10.1037/emo0001228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
Abstract
The experience of rejection and disconnection reliably amplifies pain. Yet, little is known about the impact of enduring feelings of closeness, or social connectedness, on experiences of chronic pain. The current secondary analysis tested the hypothesis that greater social connectedness would predict lower chronic pain ratings, mediated by lower depression and anxiety. In addition, based on the social-affective effects of deeper pressure, and our previous finding that deeper pressure from a weighted blanket reduced chronic pain ratings, we examined whether deeper pressure from a weighted blanket would induce greater pain relief in socially disconnected chronic pain patients. We assessed social connectedness, anxiety, and depression at baseline and pain levels before and after a remote, 7-day randomized-controlled trial of a heavy or light (control) weighted blanket in a predominately White (86%) and female (80%) sample of 95 chronic pain patients. Results revealed that lower social connectedness was associated with higher chronic pain ratings, which was mediated by anxiety, but not depression. Pressure level (light vs. deep) moderated associations between social connectedness and pain reductions, such that deeper pressure was necessary for pain relief in the most socially disconnected participants. Our findings suggest a close relationship between social connectedness and chronic pain through a mechanistic pathway of anxiety. Furthermore, our findings demonstrate that sensory-affective interventions such as a weighted blanket may be a beneficial tool for chronic pain sufferers who are prone to social disconnection, potentially by activating embodied representations of safety and social support. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Affiliation(s)
- Jennifer N. Baumgartner
- NIH Office of Disease Prevention, Office of the Director, DPCPSI, 6705 Rockledge Drive, Room 733, MSC 7990, Bethesda, MD 20892
- UC San Diego Health, Department of Anesthesiology, 9500 Gilman Drive MC 0719, La Jolla, CA 92093, 858-246-4968
| | - Michael R. Haupt
- University of California San Diego, Department of Cognitive Science, 9500 Gilman Dr, La Jolla, CA, 92093
| | - Laura K. Case
- UC San Diego Health, Department of Anesthesiology, 9500 Gilman Drive MC 0719, La Jolla, CA 92093, 858-246-4968
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Case LK, Madian N, McCall MV, Bradson ML, Liljencrantz J, Goldstein B, Alasha VJ, Zimmerman MS. Aβ-CT affective touch: Touch pleasantness ratings for gentle stroking and deep pressure exhibit dependence on A-fibers. eNeuro 2023; 10:ENEURO.0504-22.2023. [PMID: 37169581 DOI: 10.1523/eneuro.0504-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 04/17/2023] [Accepted: 05/03/2023] [Indexed: 05/13/2023] Open
Abstract
Gentle stroking of the skin is a common social touch behavior with positive affective consequences. A preference for slow versus fast stroking of hairy skin has been closely linked to the firing of unmyelinated C-tactile (CT) somatosensory afferents. Because the firing of CT afferents strongly correlates with touch pleasantness, the CT pathway has been considered a social-affective sensory pathway. Recently, ablation of the spinothalamic pathway- thought to convey all C-fiber sensations- in patients with cancer pain impaired pain, temperature, and itch, but not ratings of pleasant touch. This suggested integration of afferent A and CT fiber input in the spinal cord, or mechanoreceptive A-fiber contributions to computations of touch pleasantness in the brain. However, contribution of mechanoreceptive A-fibers to touch pleasantness- in humans without pain- remains unknown. In the current, single-blinded study we performed two types of peripheral nerve blocks in healthy adults to temporarily eliminate the contribution of A-fibers to touch perception. Our findings show that when mechanoreceptive A-fiber function is greatly diminished, the perceived intensity and pleasantness of both gentle stroking and deep pressure are nearly abolished. These findings demonstrate that explicit perception of the pleasantness of CT-targeted brushing and pressure both critically depend on afferent A-fibers.Significance StatementIn the current study we performed two types of peripheral nerve blocks in healthy adults to temporarily eliminate the contribution of A-fiber afferents to touch perception. We show that when afferent A-fiber function is greatly diminished, the perceived intensity and pleasantness of gentle stroking are nearly abolished. These findings demonstrate for the first time that explicit perception of the pleasantness of C-tactile (CT)-targeted touch critically depends upon A-fiber afferents. In addition, we show the same outcome for deep pressure (similar to hugs and massage), another form of social-affective touch we have previously validated in the lab. Together these findings demonstrate that social touch is not conveyed solely by the CT pathway.
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Affiliation(s)
- Laura K Case
- Department of Anesthesiology, UC San Diego School of Medicine, CA, USA, 92037
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, USA, 20892
| | - Nicholas Madian
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, USA, 20892
| | - Micaela V McCall
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, USA, 20892
| | - Megan L Bradson
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, USA, 20892
| | - Jaquette Liljencrantz
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, USA, 20892
- Department of Anesthesiology and Intensive Care, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
| | - Benjamin Goldstein
- Department of Anesthesiology, UC San Diego School of Medicine, CA, USA, 92037
| | - Vincent J Alasha
- Department of Anesthesiology, UC San Diego School of Medicine, CA, USA, 92037
| | - Marisa S Zimmerman
- Department of Anesthesiology, UC San Diego School of Medicine, CA, USA, 92037
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Baumgartner JN, Quintana D, Leija L, Schuster NM, Bruno KA, Castellanos JP, Case LK. Widespread Pressure Delivered by a Weighted Blanket Reduces Chronic Pain: A Randomized Controlled Trial. J Pain 2021; 23:156-174. [PMID: 34425251 DOI: 10.1016/j.jpain.2021.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/08/2021] [Accepted: 07/22/2021] [Indexed: 11/30/2022]
Abstract
Pleasant sensation is an underexplored avenue for modulation of chronic pain. Deeper pressure is perceived as pleasant and calming, and can improve sleep. Although pressure can reduce acute pain, its effect on chronic pain is poorly characterized. The current remote, double-blind, randomized controlled trial tested the hypothesis that wearing a heavy weighted blanket - providing widespread pressure to the body - relative to a light weighted blanket would reduce ratings of chronic pain, mediated by improvements in anxiety and sleep. Ninety-four adults with chronic pain were randomized to wear a 15-lb. (heavy) or 5-lb. (light) weighted blanket during a brief trial and overnight for one week. Measures of anxiety and chronic pain were collected pre- and post-intervention, and ratings of pain intensity, anxiety, and sleep were collected daily. After controlling for expectations and trait anxiety, the heavy weighted blanket produced significantly greater reductions in broad perceptions of chronic pain than the light weighted blanket (Cohen's f = .19, CI [-1.97, -.91]). This effect was stronger in individuals with high trait anxiety (P = .02). However, weighted blankets did not alter pain intensity ratings. Pain reductions were not mediated by anxiety or sleep. Given that the heavy weighted blanket was associated with greater modulation of affective versus sensory aspects of chronic pain, we propose that the observed reductions are due to interoceptive and social/affective effects of deeper pressure. Overall, we demonstrate that widespread pressure from a weighted blanket can reduce the severity of chronic pain, offering an accessible, home-based tool for chronic pain. The study purpose, targeted condition, study design, and primary and secondary outcomes were pre-registered in ClinicalTrials.gov (NCT04447885: "Weighted Blankets and Chronic Pain"). Perspective: This randomized-controlled trial showed that a 15-lb weighted blanket produced significantly greater reductions in broad perceptions of chronic pain relative to a 5-lb weighted blanket, particularly in highly anxious individuals. These findings are relevant to patients and providers seeking home-based, nondrug therapies for chronic pain relief.
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Affiliation(s)
- Jennifer N Baumgartner
- Department of Anesthesiology, University of California San Diego Health, La Jolla, California
| | - Desiree Quintana
- Department of Anesthesiology, University of California San Diego Health, La Jolla, California
| | - Linda Leija
- Department of Anesthesiology, University of California San Diego Health, La Jolla, California
| | - Nathaniel M Schuster
- Department of Anesthesiology, University of California San Diego Health, La Jolla, California
| | - Kelly A Bruno
- Department of Anesthesiology, University of California San Diego Health, La Jolla, California
| | - Joel P Castellanos
- Department of Anesthesiology, University of California San Diego Health, La Jolla, California
| | - Laura K Case
- Department of Anesthesiology, University of California San Diego Health, La Jolla, California.
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Case LK, Liljencrantz J, McCall MV, Bradson M, Necaise A, Tubbs J, Olausson H, Wang B, Bushnell MC. Pleasant Deep Pressure: Expanding the Social Touch Hypothesis. Neuroscience 2020; 464:3-11. [PMID: 32768616 DOI: 10.1016/j.neuroscience.2020.07.050] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 07/20/2020] [Accepted: 07/21/2020] [Indexed: 11/25/2022]
Abstract
Neuroscientific research on pleasant touch has focused on the C-tactile pathway for gentle stroking and has successfully explained how these sensory fibers transmit information about affective social touch to the brain and induce sensations of pleasantness. The C-tactile social/affective touch hypothesis even proposes that C-tactile fibers form a privileged pathway underlying social touch. However, deep pressure is a type of touch commonly considered pleasant and calming, occurring in hugs, cuddling, and massage. In this paper we introduce a paradigm for studying pleasant deep pressure and propose that it constitutes another important form of social touch. We describe development of the oscillating compression sleeve (OCS) as one approach to administering deep pressure and demonstrate that this touch is perceived as pleasant and calming. Further, we show that deep pressure can be imaged with functional magnetic resonance imaging (MRI) using the air-pressure-driven OCS and that deep pressure activates brain regions highly similar to those that respond to C-tactile stroking, as well as regions not activated by stroking. We propose that deep pressure constitutes another social touch pathway of evolutionary importance signaling the close proximity of conspecifics.
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Affiliation(s)
- Laura K Case
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United States; Department of Anesthesiology, UC San Diego School of Medicine, La Jolla, CA, United States.
| | - Jaquette Liljencrantz
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United States
| | - Micaela V McCall
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United States
| | - Megan Bradson
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United States
| | - Aaron Necaise
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United States
| | - Justin Tubbs
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United States
| | - Håkan Olausson
- Center for Social and Affective Neuroscience, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - Binquan Wang
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United States
| | - M Catherine Bushnell
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United States
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Case LK, Laubacher CM, Richards EA, Grossman M, Atlas LY, Parker S, Bushnell MC. Is placebo analgesia for heat pain a sensory effect? An exploratory study on minimizing the influence of response bias. Neurobiol Pain 2019; 5. [PMID: 31080912 PMCID: PMC6505707 DOI: 10.1016/j.ynpai.2018.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We explored whether placebo analgesia alters afferent nociceptive processing. Healthy adult participants received a standard heat placebo induction procedure. Placebo manipulation was modified to reduce experimenter demand. A novel inter-arm sensory discrimination task was administered. Only placebo responders showed changes in discriminative ability.
We explored the ongoing question of whether placebo analgesia alters afferent nociceptive processing in a novel paradigm designed to minimize the role of response bias in placebo measurement. First, healthy adult participants received a standard heat placebo induction and conditioning procedure using a topical “analgesic” cream applied to one arm. During a subsequent placebo testing procedure, participants rated stimuli on the placebo-treated arm and untreated arm, using a task that minimized subjects’ ability to guess the expected response, thus reducing experimenter demand. Retrospectively participants reported moderate analgesia effectiveness (mean = 5.3/10), but for individual temperature ratings, only 2 subjects exhibited a perceptual placebo response >5 points. Next, these subjects completed a novel, exploratory task designed to measure changes in inter-arm in discriminative accuracy that would be expected from changes in afferent nociception. Both placebo responders (but no non-responders) showed reduced discriminative ability when the hotter stimulus occurred on the placebo arm, an effect consistent with alterations in nociceptive afferent flow and unlikely to be caused by response bias.
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Affiliation(s)
- Laura K Case
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United State
| | - Claire M Laubacher
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United State
| | - Emily A Richards
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United State
| | - Matthew Grossman
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United State
| | - Lauren Y Atlas
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United State.,National Institutes on Drug Abuse, NIH, Baltimore, MD, United States
| | - Scott Parker
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United State.,Department of Psychology, American University, United States
| | - M Catherine Bushnell
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, United State
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Case LK, Jackson P, Kinkel R, Mills PJ. Guided Imagery Improves Mood, Fatigue, and Quality of Life in Individuals With Multiple Sclerosis: An Exploratory Efficacy Trial of Healing Light Guided Imagery. J Evid Based Integr Med 2019; 23:2515690X17748744. [PMID: 29405761 PMCID: PMC5871039 DOI: 10.1177/2515690x17748744] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Multiple sclerosis is a disabling and progressive neurological disease that has significant negative effects on health-related quality of life. This exploratory efficacy study examined the effects of Healing Light Guided Imagery (HLGI), a novel variant of guided imagery, compared with a wait-list control in patients with relapsing-remitting multiple sclerosis. Changes in the Beck Depression Inventory, Fatigue Severity Scale, and Multiple Sclerosis Quality of Life instrument (physical and mental components) were compared between groups. Patients who completed HLGI (N = 9) showed significant reductions in depressed mood (P < .05) and fatigue (P < .01) and showed significant gains in physical (P = .01) and mental (P < .01) quality of life compared with journaling (N = 8). Our results suggest that HLGI can improve self-reported physical and mental well-being in patients with relapsing-remitting multiple sclerosis. Further research is needed to study the effectiveness of this therapy, as well as its mind-body mechanisms of action.
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Affiliation(s)
- Laura K Case
- 1 University of California San Diego, La Jolla, CA, USA.,Current affiliation: National Center for Complementary and Integrative Health, Bethesda, MD, USA
| | - Paula Jackson
- 1 University of California San Diego, La Jolla, CA, USA
| | - Revere Kinkel
- 1 University of California San Diego, La Jolla, CA, USA
| | - Paul J Mills
- 1 University of California San Diego, La Jolla, CA, USA
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Case LK, Brang D, Landazuri R, Viswanathan P, Ramachandran VS. Altered White Matter and Sensory Response to Bodily Sensation in Female-to-Male Transgender Individuals. Arch Sex Behav 2017; 46:1223-1237. [PMID: 27646840 PMCID: PMC5357597 DOI: 10.1007/s10508-016-0850-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 08/22/2016] [Accepted: 08/24/2016] [Indexed: 06/06/2023]
Abstract
While most people take identification with their body for granted, conditions such as phantom limb pain, alien hand syndrome, and xenomelia suggest that the feeling of bodily congruence is constructed and susceptible to alteration. Individuals with xenomelia typically experience one of their limbs as over-present and aversive, leading to a desire to amputate the limb. Similarly, many transgender individuals describe their untreated sexed body parts as incongruent and aversive, and many experience phantom body parts of the sex they identify with (Ramachandran, 2008). This experience may relate to differences in brain representation of the sexed body part, as suggested in xenomelia (McGeoch et al., 2011). We utilized magnetoencephalography imaging to record brain activity during somatosensory stimulation of the breast-a body part that feels incongruent to most presurgical female-to-male (FtM)-identified transgender individuals-and the hand, a body part that feels congruent. We measured the sensory evoked response in right hemisphere somatosensory and body-related brain areas and found significantly reduced activation in the supramarginal gyrus and secondary somatosensory cortex, but increased activation at the temporal pole for chest sensation in the FtM group (N = 8) relative to non-transgender females (N = 8). In addition, we found increased white matter coherence in the supramarginal gyrus and temporal pole and decreased white matter diffusivity in the anterior insula and temporal pole in the FtM group. These findings suggest that dysphoria related to gender-incongruent body parts in FtM individuals may be tied to differences in neural representation of the body and altered white matter connectivity.
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Affiliation(s)
- Laura K Case
- Department of Psychology, University of California, San Diego, CA, USA.
- Pain and Integrative Neuroscience Branch, National Center for Complementary and Integrative Health, Bethesda, MD, 20892, USA.
- Department of Cognitive Science, University of California, San Diego, CA, USA.
| | - David Brang
- Department of Psychology, University of California, San Diego, CA, USA
- Department of Psychology, University of Michigan, Ann Arbor, MI, USA
- Department of Cognitive Science, University of California, San Diego, CA, USA
| | - Rosalynn Landazuri
- Department of Psychology, University of California, San Diego, CA, USA
- Department of Cognitive Science, University of California, San Diego, CA, USA
| | - Pavitra Viswanathan
- Department of Psychology, University of California, San Diego, CA, USA
- Department of Cognitive Science, University of California, San Diego, CA, USA
| | - Vilayanur S Ramachandran
- Department of Psychology, University of California, San Diego, CA, USA
- Department of Cognitive Science, University of California, San Diego, CA, USA
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Case LK, Laubacher CM, Richards EA, Spagnolo PA, Olausson H, Bushnell MC. Inhibitory rTMS of secondary somatosensory cortex reduces intensity but not pleasantness of gentle touch. Neurosci Lett 2017; 653:84-91. [PMID: 28529174 DOI: 10.1016/j.neulet.2017.05.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 05/02/2017] [Accepted: 05/03/2017] [Indexed: 12/22/2022]
Abstract
Research suggests that the discriminative and affective aspects of touch are processed differently in the brain. Primary somatosensory cortex is strongly implicated in touch discrimination, whereas insular and prefronal regions have been associated with pleasantness aspects of touch. However, the role of secondary somatosensory cortex (S2) is less clear. In the current study we used inhibitory repetitive transcranial magnetic stimulation (rTMS) to temporarily deactivate S2 and probe its role in touch perception. Nineteen healthy adults received two sessions of 1-Hz rTMS on separate days, one targeting right S2 and the other targeting the vertex (control). Before and after rTMS, subjects rated the intensity and pleasantness of slow and fast gentle brushing of the hand and performed a 2-point tactile discrimination task, followed by fMRI during additional brushing. rTMS to S2 (but not vertex) decreased intensity ratings of fast brushing, without altering touch pleasantness or spatial discrimination. MRI showed a reduced response to brushing in S2 (but not in S1 or insula) after S2 rTMS. Together, our results show that reducing touch-evoked activity in S2 decreases perceived touch intensity, suggesting a causal role of S2 in touch intensity perception.
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Affiliation(s)
- Laura K Case
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, USA.
| | - Claire M Laubacher
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, USA
| | - Emily A Richards
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, USA
| | - P A Spagnolo
- National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD, USA
| | - Håkan Olausson
- Center for Social and Affective Neuroscience, Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden
| | - M Catherine Bushnell
- National Center for Complementary and Integrative Health, NIH, Bethesda, MD, USA
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Bearoff F, Del Rio R, Case LK, Dragon JA, Nguyen-Vu T, Lin CY, Blankenhorn EP, Teuscher C, Krementsov DN. Natural genetic variation profoundly regulates gene expression in immune cells and dictates susceptibility to CNS autoimmunity. Genes Immun 2016; 17:386-395. [PMID: 27653816 PMCID: PMC5133152 DOI: 10.1038/gene.2016.37] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 02/08/2023]
Abstract
Regulation of gene expression in immune cells is known to be under genetic control, and likely contributes to susceptibility to autoimmune diseases such as multiple sclerosis (MS). How this occurs in concert across multiple immune cell types is poorly understood. Using a mouse model that harnesses the genetic diversity of wild-derived mice, more accurately reflecting genetically diverse human populations, we provide an extensive characterization of the genetic regulation of gene expression in five different naive immune cell types relevant to MS. The immune cell transcriptome is shown to be under profound genetic control, exhibiting diverse patterns: global, cell-specific and sex-specific. Bioinformatic analysis of the genetically controlled transcript networks reveals reduced cell type specificity and inflammatory activity in wild-derived PWD/PhJ mice, compared with the conventional laboratory strain C57BL/6J. Additionally, candidate MS-GWAS (genome-wide association study candidate genes for MS susceptibility) genes were significantly enriched among transcripts overrepresented in C57BL/6J cells compared with PWD. These expression level differences correlate with robust differences in susceptibility to experimental autoimmune encephalomyelitis, the principal model of MS, and skewing of the encephalitogenic T-cell responses. Taken together, our results provide functional insights into the genetic regulation of the immune transcriptome, and shed light on how this in turn contributes to susceptibility to autoimmune disease.
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Affiliation(s)
- F Bearoff
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA
| | - R Del Rio
- Department of Medicine, University of Vermont, Burlington, VT, USA
| | - L K Case
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - J A Dragon
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, VT, USA
| | - T Nguyen-Vu
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - C-Y Lin
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX, USA
| | - E P Blankenhorn
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA, USA
| | - C Teuscher
- Department of Medicine, University of Vermont, Burlington, VT, USA
- Department of Pathology, University of Vermont, Burlington, VT, USA
| | - D N Krementsov
- Department of Medicine, University of Vermont, Burlington, VT, USA
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Case LK, Laubacher CM, Olausson H, Wang B, Spagnolo PA, Bushnell MC. Encoding of Touch Intensity But Not Pleasantness in Human Primary Somatosensory Cortex. J Neurosci 2016; 36:5850-60. [PMID: 27225773 PMCID: PMC4879201 DOI: 10.1523/jneurosci.1130-15.2016] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/19/2016] [Accepted: 04/21/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Growing interest in affective touch has delineated a neural network that bypasses primary somatosensory cortex (S1). Several recent studies, however, have cast doubt on the segregation of touch discrimination and affect, suggesting that S1 also encodes affective qualities. We used functional magnetic resonance imaging (fMRI) and repetitive transcranial magnetic stimulation (rTMS) to examine the role of S1 in processing touch intensity and pleasantness. Twenty-six healthy human adults rated brushing on the hand during fMRI. Intensity ratings significantly predicted activation in S1, whereas pleasantness ratings predicted activation only in the anterior cingulate cortex. Nineteen subjects also received inhibitory rTMS over right hemisphere S1 and the vertex (control). After S1 rTMS, but not after vertex rTMS, sensory discrimination was reduced and subjects with reduced sensory discrimination rated touch as more intense. In contrast, rTMS did not alter ratings of touch pleasantness. Our findings support divergent neural processing of touch intensity and pleasantness, with affective touch encoded outside of S1. SIGNIFICANCE STATEMENT Growing interest in affective touch has identified a neural network that bypasses primary somatosensory cortex (S1). Several recent studies, however, cast doubt on the separation of touch discrimination and affect. We used functional magnetic resonance imaging and repetitive transcranial magnetic stimulation to demonstrate the representation of touch discrimination and intensity in S1, but the representation of pleasantness in the anterior cingulate cortex, not S1. Our findings support divergent neural processing of touch intensity and pleasantness, with affective touch encoded outside of S1. Our study contributes to growing delineation of the affective touch system, a crucial step in understanding its dysregulation in numerous clinical conditions such as autism, eating disorders, depression, and chronic pain.
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Affiliation(s)
- Laura K Case
- National Center for Complementary and Integrative Health and
| | | | - Håkan Olausson
- Department of Clinical and Experimental Medicine, Linköping University, 581 83 Linköping, Sweden
| | - Binquan Wang
- National Center for Complementary and Integrative Health and
| | - Primavera A Spagnolo
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892, and
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Case LK, Pineda J, Ramachandran VS. Common coding and dynamic interactions between observed, imagined, and experienced motor and somatosensory activity. Neuropsychologia 2015; 79:233-45. [PMID: 25863237 DOI: 10.1016/j.neuropsychologia.2015.04.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 03/01/2015] [Accepted: 04/03/2015] [Indexed: 01/25/2023]
Abstract
Motor imagery and perception - considered generally as forms of motor simulation - share overlapping neural representations with motor production. While much research has focused on the extent of this "common coding," less attention has been paid to how these overlapping representations interact. How do imagined, observed, or produced actions influence one another, and how do we maintain control over our perception and behavior? In the first part of this review we describe interactions between motor production and motor simulation, and explore apparent regulatory mechanisms that balance these processes. Next, we consider the somatosensory system. Numerous studies now support a "sensory mirror system" comprised of neural representations activated by either afferent sensation or vicarious sensation. In the second part of this review we summarize evidence for shared representations of sensation and sensory simulation (including imagery and observed sensation), and suggest that similar interactions and regulation of simulation occur in the somatosensory domain as in the motor domain. We suggest that both motor and somatosensory simulations are flexibly regulated to support simulations congruent with our sensorimotor experience and goals and suppress or separate the influence of those that are not. These regulatory mechanisms are frequently revealed by cases of brain injury but can also be employed to facilitate sensorimotor rehabilitation.
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Affiliation(s)
- Laura K Case
- Center for Brain and Cognition, University of California, San Diego, USA; Pain and Integrative Neuroscience Branch, National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, MD, USA.
| | - Jaime Pineda
- Department of Cognitive Science, University of California, San Diego, USA
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13
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Abstract
We have previously suggested that the social symptoms of autism spectrum disorder (ASD) could be caused in part by a dysfunctional mirror neuron system (MNS). Since the recursive activity of a functioning MNS might enable the brain to integrate visual and motor sensations into a coherent body schema, the deficits in self-awareness often seen in ASD might be caused by the same mirror neuron dysfunction. CL is an autistic adolescent who is profoundly fascinated with his reflection, looking in mirrors at every opportunity. We demonstrate that CL's abnormal gait improves significantly when using a mirror for visual feedback. We also show that both the fascination and the happiness that CL derives from looking at a computer-generated reflection diminish when a delay is introduced between the camera input and screen output. We believe that immediate, real-time visual feedback allows CL to integrate motor sensations with external visual ones into a coherent body schema that he cannot internally generate, perhaps due to a dysfunctional MNS.
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Affiliation(s)
- Nicholas B Root
- a Department of Psychology , University of California , San Diego , CA , USA
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Kenworthy L, Wallace GL, Birn R, Milleville SC, Case LK, Bandettini PA, Martin A. Aberrant neural mediation of verbal fluency in autism spectrum disorders. Brain Cogn 2013; 83:218-26. [PMID: 24056237 DOI: 10.1016/j.bandc.2013.08.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 08/09/2013] [Accepted: 08/24/2013] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Contrasts of verbal fluency and automatic speech provide an opportunity to evaluate the neural underpinnings of generativity and flexibility in autism spectrum disorders (ASD). METHOD We used functional magnetic resonance imaging (fMRI) to contrast brain activity in high functioning ASD (n=17, mean verbal IQ=117) and neurotypical (NT; n=20, mean verbal IQ=112) adolescent and young adult males (12-23years). Participants responded to three word generation conditions: automatic speech (reciting months), category fluency, and letter fluency. RESULTS Our paradigm closely mirrored behavioral fluency tasks by requiring overt, free recall word generation while controlling for differences in verbal output between the groups and systematically increasing the task demand. The ASD group showed reduced neural response compared to the NT participants during fluency tasks in multiple regions of left anterior and posterior cortices, and sub-cortical structures. Six of these regions fell in cortico-striatal circuits previously linked to repetitive behaviors (Langen, Durston, Kas, van Engeland, & Staal, 2011), and activity in two of them (putamen and thalamus) was negatively correlated with autism repetitive behavior symptoms in the ASD group. In addition, response in left inferior frontal gyrus was differentially modulated in the ASD, relative to the NT, group as a function of task demand. CONCLUSIONS These data indicate a specific, atypical brain response in ASD to demanding generativity tasks that may have relevance to repetitive behavior symptoms in ASD as well as to difficulties generating original verbal responses.
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Affiliation(s)
- Lauren Kenworthy
- Laboratory of Brain and Cognition, National Institute of Mental Health, 10 Center Drive, Room 4C104, MSC 1366, Bethesda, MD 20892-1366, USA; Center for Autism Spectrum Disorders, Children's National Medical Center, 15245 Shady Grove Road, Suite 350, Rockville, MD 20850, USA.
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Case LK, Gosavi R, Ramachandran VS. Heightened motor and sensory (mirror-touch) referral induced by nerve block or topical anesthetic. Neuropsychologia 2013; 51:1823-8. [DOI: 10.1016/j.neuropsychologia.2013.06.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/25/2013] [Accepted: 06/10/2013] [Indexed: 10/26/2022]
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Case LK, Ramachandran VS. Alternating gender incongruity: A new neuropsychiatric syndrome providing insight into the dynamic plasticity of brain-sex. Med Hypotheses 2012; 78:626-31. [DOI: 10.1016/j.mehy.2012.01.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 01/03/2012] [Accepted: 01/25/2012] [Indexed: 10/28/2022]
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Wallace GL, Case LK, Harms MB, Silvers JA, Kenworthy L, Martin A. Diminished sensitivity to sad facial expressions in high functioning autism spectrum disorders is associated with symptomatology and adaptive functioning. J Autism Dev Disord 2011; 41:1475-86. [PMID: 21347615 PMCID: PMC3448486 DOI: 10.1007/s10803-010-1170-0] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Prior studies implicate facial emotion recognition (FER) difficulties among individuals with autism spectrum disorders (ASD); however, many investigations focus on FER accuracy alone and few examine ecological validity through links with everyday functioning. We compared FER accuracy and perceptual sensitivity (from neutral to full expression) between 42 adolescents with high functioning (IQ > 80) ASD and 31 typically developing adolescents (matched on age, IQ, sex ratio) across six basic emotions and examined links between FER and symptomatology/adaptive functioning within the ASD group. Adolescents with ASD required more intense facial expressions for accurate emotion identification. Controlling for this overall group difference revealed particularly diminished sensitivity to sad facial expressions in ASD, which was uniquely correlated with ratings of autism-related behavior and adaptive functioning.
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Affiliation(s)
- Gregory L Wallace
- Laboratory of Brain & Cognition, National Institute of Mental Health, 10 Center Drive, Room 4C104, MSC 1366, Bethesda, MD 20892-1366, USA.
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Abstract
A student volunteer was asked to stand just behind a mannequin so that the student was looking at the back of the mannequin's plastic head. The experimenter stood off to one side and used her two hands to stroke and tap the back of the student's head in perfect synchrony with the back of the mannequin's head. After 1-2 min the majority of naive subjects tested began experiencing the sensations as emerging from the mannequin's head rather than from their own, demonstrating a novel 'phantom-head' illusion. The fact that sensory referral here occurs to a part of the body that is not normally visually accessible challenges the leading Hebbian explanation of the well-studied rubber-hand illusion.
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Affiliation(s)
- Vilayanur S Ramachandran
- Center for Brain and Cognition, University of California at San Diego, McGill Hall, 9500 Gilman Drive, La Jolla, CA 92093-0109, USA.
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Case LK, Abrams RA, Ramachandran VS. Immediate interpersonal and intermanual referral of sensations following anesthetic block of one arm. ACTA ACUST UNITED AC 2011; 67:1521-3. [PMID: 21149815 DOI: 10.1001/archneurol.2010.290] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVES To explore whether interpersonal and intermanual sensory referral occurs following anesthetic block of a limb and to test theories of disinhibition of mirror neuron activity and transcallosal referral. DESIGN Case series. SETTING Outpatient surgery at the University of California San Diego Medical Center. PATIENTS Six patients who underwent orthopedic surgery. MAIN OUTCOME MEASURES Patient verbal ratings. RESULTS Patients with brachial plexus blocks experienced touch sensations in the anesthetized arm when watching another person's arm being touched or when the contralateral intact hand was touched. CONCLUSIONS To our knowledge, this is the first demonstration of rapid reorganization of functional connectivity in the adult human brain, most likely in S2 neurons. This finding suggests that conscious perception of touch results from fluctuating mosaics of cortical excitation and inhibition between different regions within the patient's own S2 neurons and, more remarkably, from viewing others' sensations.
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Affiliation(s)
- Laura K Case
- Center for Brain and Cognition, University of California, San Diego, La Jolla, 92093-0109, USA
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Spach KM, Case LK, Noubade R, Petersen CB, McElvany B, Zalik N, Hickey WF, Blankenhorn EP, Teuscher C. Multiple linked quantitative trait loci within the Tmevd2/Eae3 interval control the severity of experimental allergic encephalomyelitis in DBA/2J mice. Genes Immun 2010; 11:649-59. [PMID: 20861860 PMCID: PMC2995842 DOI: 10.1038/gene.2010.40] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Theiler’s murine encephalomyelitis virus-induced demyelination (TMEVD) and experimental allergic encephalomyelitis (EAE) are the principal animal models of multiple sclerosis (MS). Previously we provided evidence that Tmevd2 and Eae3 may represent either a shared susceptibility locus or members of a gene complex controlling susceptibility to CNS inflammatory demyelinating disease. To explore the genetic relationship between Tmevd2 and Eae3, we generated a D2.C-Tmevd2 interval-specific congenic (ISC) line and three overlapping interval-specific recombinant congenic (ISRC) lines in which the Tmevd2 resistant allele from BALB/cByJ was introgressed onto the TMEVD-susceptible DBA/2J background. These mice, all H2d, were studied for susceptibility to EAE elicited by immunization with PLP180–199. Compared to DBA/2J mice, D2.C-Tmevd2 mice developed a significantly less severe clinical disease course and EAE pathology in the spinal cord, confirming the existence of Eae3 and its linkage to Tmevd2 in this strain combination. Compare to DBA/2J and D2.C-Tmevd2, all three ISRC lines exhibited clinical disease courses of intermediate severity. Neither differences in ex vivo antigen-specific cytokine nor proliferative responses uniquely cosegregated with differences in disease severity. These results indicate that multiple QTL within the Tmevd2/Eae3 interval influence EAE severity, one of which includes a homology region for a QTL found in MS by admixture mapping.
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Affiliation(s)
- K M Spach
- Department of Medicine, University of Vermont, Burlington, VT 05405, USA
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Jones TB, Bandettini PA, Kenworthy L, Case LK, Milleville SC, Martin A, Birn RM. Sources of group differences in functional connectivity: an investigation applied to autism spectrum disorder. Neuroimage 2009; 49:401-14. [PMID: 19646533 DOI: 10.1016/j.neuroimage.2009.07.051] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 07/17/2009] [Accepted: 07/21/2009] [Indexed: 10/20/2022] Open
Abstract
An increasing number of fMRI studies are using the correlation of low-frequency fluctuations between brain regions, believed to reflect synchronized variations in neuronal activity, to infer "functional connectivity". In studies of autism spectrum disorder (ASD), decreases in this measure of connectivity have been found by focusing on the response to task modulation, by using only the rest periods, or by analyzing purely resting-state data. This difference in connectivity, however, could result from a number of different mechanisms--differences in noise, task-related fluctuations, task performance, or spontaneous neuronal activity. In this study, we investigate the difference in functional connectivity between adolescents with high-functioning ASD and typically developing control subjects by examining the residual fluctuations occurring on top of the fMRI response to an overt verbal fluency task. We find decreased correlations of these residuals (a decreased "connectivity") in ASD subjects. Furthermore, we find that this decrease was not due to task-related effects, block-to-block variations in task performance, or increased noise, and the difference was greatest when primarily rest periods are considered. These findings suggest that the estimate of disrupted functional connectivity in ASD is likely driven by differences in task-unrelated neuronal fluctuations.
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Affiliation(s)
- Tyler B Jones
- Laboratory of Brain and Cognition, National Institute of Mental Health/NIH, Bethesda, MD 20892, USA
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