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Armand S, Langley C, Johansen A, Ozenne B, Overgaard-Hansen O, Larsen K, Jensen PS, Knudsen GM, Sahakian BJ, Stenbæk DS, Fisher PM. Functional brain responses to emotional faces after three to five weeks of intake of escitalopram in healthy individuals: a double-blind, placebo-controlled randomised study. Sci Rep 2024; 14:3149. [PMID: 38326352 PMCID: PMC10850508 DOI: 10.1038/s41598-024-51448-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 01/04/2024] [Indexed: 02/09/2024] Open
Abstract
Short-term intake of selective serotonin reuptake inhibitors (SSRIs) modulates threat-related amygdala responses in healthy individuals. However, how SSRI intake over a clinically relevant time period modulates threat-related amygdala responses is less clear. In a semi-randomised, double-blind, placebo-controlled study of 64 healthy individuals (SSRI n = 32, placebo n = 32), we examined the effect of 3-5 weeks of SSRI escitalopram (20 mg daily) on brain response to angry, fearful and neutral faces using BOLD fMRI. Data was analysed using a whole-brain region-wise approach extracting standardised effects (i.e., Cohen's D). The study was conducted at the Copenhagen University Hospital. A priori, we hypothesised that SSRI would attenuate amygdala responses to angry and fearful faces but not to neutral ones. Whether SSRI modulates correlations between amygdala responses to emotional faces and negative mood states was also explored. Compared to placebo, 3-5 weeks of SSRI intake did not significantly affect the amygdala response to angry, fearful, or neutral faces (|Cohen's D|< 0.2, PFWER = 1). Whole-brain, region-wise analyses revealed significant differences in frontal (|Cohen's D|< 0.6, PFWER < .01) and occipital regions (|Cohen's D|< 0.5, PFWER < .01). SSRI did not modulate correlations between amygdala responses to emotional faces and negative mood states. Our findings indicate that a 3-5 week SSRI intake impacts cortical responses to emotional stimuli, an effect possibly involved in SSRI's therapeutic efficacy.Trial registration Clinical Trials NCT04239339.
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Affiliation(s)
- Sophia Armand
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Department of Psychology, Faculty of Social Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Annette Johansen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Brice Ozenne
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Section of Biostatistics, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Oliver Overgaard-Hansen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Kristian Larsen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter Steen Jensen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Gitte Moos Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Dea Siggard Stenbæk
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
- Department of Psychology, Faculty of Social Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Patrick MacDonald Fisher
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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2
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LeDuke DO, Borio M, Miranda R, Tye KM. Anxiety and depression: A top-down, bottom-up model of circuit function. Ann N Y Acad Sci 2023; 1525:70-87. [PMID: 37129246 PMCID: PMC10695657 DOI: 10.1111/nyas.14997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A functional interplay of bottom-up and top-down processing allows an individual to appropriately respond to the dynamic environment around them. These processing modalities can be represented as attractor states using a dynamical systems model of the brain. The transition probability to move from one attractor state to another is dependent on the stability, depth, neuromodulatory tone, and tonic changes in plasticity. However, how does the relationship between these states change in disease states, such as anxiety or depression? We describe bottom-up and top-down processing from Marr's computational-algorithmic-implementation perspective to understand depressive and anxious disease states. We illustrate examples of bottom-up processing as basolateral amygdala signaling and projections and top-down processing as medial prefrontal cortex internal signaling and projections. Understanding these internal processing dynamics can help us better model the multifaceted elements of anxiety and depression.
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Affiliation(s)
- Deryn O. LeDuke
- Salk Institute for Biological Studies, La Jolla, California, USA
- Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California, USA
| | - Matilde Borio
- Salk Institute for Biological Studies, La Jolla, California, USA
| | - Raymundo Miranda
- Salk Institute for Biological Studies, La Jolla, California, USA
- Neurosciences Graduate Program, University of California San Diego, La Jolla, California, USA
| | - Kay M. Tye
- Salk Institute for Biological Studies, La Jolla, California, USA
- Howard Hughes Medical Institute, La Jolla, California, USA
- Kavli Institute for the Brain and Mind, La Jolla, California, USA
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3
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Sankar A, Ozenne B, Dam VH, Svarer C, Jørgensen MB, Miskowiak KW, Frokjaer VG, Knudsen GM, Fisher PM. Association between brain serotonin 4 receptor binding and reactivity to emotional faces in depressed and healthy individuals. Transl Psychiatry 2023; 13:165. [PMID: 37169780 PMCID: PMC10175268 DOI: 10.1038/s41398-023-02440-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 03/30/2023] [Accepted: 04/19/2023] [Indexed: 05/13/2023] Open
Abstract
Brain serotonergic (5-HT) signaling is posited to modulate neural responses to emotional stimuli. Dysfunction in 5-HT signaling is implicated in major depressive disorder (MDD), a disorder associated with significant disturbances in emotion processing. In MDD, recent evidence points to altered 5-HT4 receptor (5-HT4R) levels, a promising target for antidepressant treatment. However, how these alterations influence neural processing of emotions in MDD remains poorly understood. This is the first study to examine the association between 5-HT4R binding and neural responses to emotions in patients with MDD and healthy controls. The study included one hundred and thirty-eight participants, comprising 88 outpatients with MDD from the NeuroPharm clinical trial (ClinicalTrials.gov identifier: NCT02869035) and 50 healthy controls. Participants underwent an [11C]SB207145 positron emission tomography (PET) scan to quantify 5-HT4R binding (BPND) and a functional magnetic resonance imaging (fMRI) scan during which they performed an emotional face matching task. We examined the association between regional 5-HT4R binding and corticolimbic responses to emotional faces using a linear latent variable model, including whether this association was moderated by depression status. We observed a positive correlation between 5-HT4R BPND and the corticolimbic response to emotional faces across participants (r = 0.20, p = 0.03). This association did not differ between groups (parameter estimate difference = 0.002, 95% CI = -0.008: 0.013, p = 0.72). Thus, in the largest PET/fMRI study of associations between serotonergic signaling and brain function, we found a positive association between 5-HT4R binding and neural responses to emotions that appear unaltered in MDD. Future clinical trials with novel pharmacological agents targeting 5-HT4R are needed to confirm whether they ameliorate emotion processing biases in MDD.
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Affiliation(s)
- Anjali Sankar
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Brice Ozenne
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Department of Public Health, Section of Biostatistics, University of Copenhagen, Copenhagen, Denmark
| | - Vibeke H Dam
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Claus Svarer
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Martin B Jørgensen
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Psychiatric Center Copenhagen, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Kamilla W Miskowiak
- Neurocognition and Emotion in Affective Disorders (NEAD) Centre, Mental Health Services, Capital Region of Denmark, and Department of Psychology, University of Copenhagen, Copenhagen, Denmark
- Department of Psychology, University of Copenhagen, Copenhagen, Denmark
| | - Vibe G Frokjaer
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Psychiatric Center Copenhagen, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Patrick M Fisher
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
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4
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Clarke RE, Voigt K, Reichenbach A, Stark R, Bharania U, Dempsey H, Lockie SH, Mequinion M, Lemus M, Wei B, Reed F, Rawlinson S, Nunez-Iglesias J, Foldi CJ, Kravitz AV, Verdejo-Garcia A, Andrews ZB. Identification of a Stress-Sensitive Anorexigenic Neurocircuit From Medial Prefrontal Cortex to Lateral Hypothalamus. Biol Psychiatry 2023; 93:309-321. [PMID: 36400605 DOI: 10.1016/j.biopsych.2022.08.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 08/04/2022] [Accepted: 08/04/2022] [Indexed: 01/24/2023]
Abstract
BACKGROUND A greater understanding of how the brain controls appetite is fundamental to developing new approaches for treating diseases characterized by dysfunctional feeding behavior, such as obesity and anorexia nervosa. METHODS By modeling neural network dynamics related to homeostatic state and body mass index, we identified a novel pathway projecting from the medial prefrontal cortex (mPFC) to the lateral hypothalamus (LH) in humans (n = 53). We then assessed the physiological role and dissected the function of this mPFC-LH circuit in mice. RESULTS In vivo recordings of population calcium activity revealed that this glutamatergic mPFC-LH pathway is activated in response to acute stressors and inhibited during food consumption, suggesting a role in stress-related control over food intake. Consistent with this role, inhibition of this circuit increased feeding and sucrose seeking during mild stressors, but not under nonstressful conditions. Finally, chemogenetic or optogenetic activation of the mPFC-LH pathway is sufficient to suppress food intake and sucrose seeking in mice. CONCLUSIONS These studies identify a glutamatergic mPFC-LH circuit as a novel stress-sensitive anorexigenic neural pathway involved in the cortical control of food intake.
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Affiliation(s)
- Rachel E Clarke
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Katharina Voigt
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia
| | - Alex Reichenbach
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Romana Stark
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Urvi Bharania
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Harry Dempsey
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Sarah H Lockie
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Mathieu Mequinion
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Moyra Lemus
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Bowen Wei
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Felicia Reed
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Sasha Rawlinson
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Juan Nunez-Iglesias
- Monash Biomedicine Discovery Institute and Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Claire J Foldi
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Alexxai V Kravitz
- Departments of Psychiatry, Anesthesiology, and Neuroscience, Washington University in St. Louis, St. Louis, Missouri
| | - Antonio Verdejo-Garcia
- Turner Institute for Brain and Mental Health, Monash University, Clayton, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Victoria, Australia.
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5
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Fisher PM, Ozenne B, Ganz M, Frokjaer VG, Dam VN, Penninx BW, Sankar A, Miskowiak K, Jensen PS, Knudsen GM, Jorgensen MB. Emotional faces processing in major depressive disorder and prediction of antidepressant treatment response: A NeuroPharm study. J Psychopharmacol 2022; 36:626-636. [PMID: 35549538 DOI: 10.1177/02698811221089035] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Major depressive disorder (MDD) is a prevalent neuropsychiatric illness for which it is important to resolve underlying brain mechanisms. Current treatments are often unsuccessful, precipitating a need to identify predictive markers. AIM We evaluated (1) alterations in brain responses to an emotional faces functional magnetic resonance imaging (fMRI) paradigm in individuals with MDD, compared to controls, (2) whether pretreatment brain responses predicted antidepressant treatment response, and (3) pre-post change in brain responses following treatment. METHODS Eighty-nine medication-free, depressed individuals and 115 healthy controls completed the fMRI paradigm. Depressed individuals completed a nonrandomized, open-label, 8-week treatment with escitalopram, including the option to switch to duloxetine after 4 weeks. We examined patient-control group differences in regional fMRI responses at baseline, whether baseline fMRI responses predicted treatment response at 8 weeks, including early life stress moderating effects, and change in fMRI responses in 36 depressed individuals rescanned following 8 weeks of treatment. RESULTS Task reaction time was 5% slower in patients. Multiple brain regions showed significant task-related responses, but we observed no statistically significant patient-control group differences (Cohen's d < 0.35). Patient pretreatment brain responses did not predict antidepressant treatment response (area under the curve of the receiver operator characteristic (AUC-ROC) < 0.6) and brain responses were not statistically significantly changed after treatment (Cohen's d < 0.33). CONCLUSION This represents the largest prediction study to date examining emotional faces fMRI features as predictors of antidepressant treatment response. Brain response to this fMRI emotional faces paradigm did not distinguish depressed individuals from healthy controls, nor was it predictive of antidepressant treatment response.Clinical Trial Registration: Site: https://clinicaltrials.gov, Trial Number: NCT02869035, Trial Title: Treatment Outcome in Major Depressive Disorder.
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Affiliation(s)
- Patrick M Fisher
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,NeuroPharm, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Brice Ozenne
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,NeuroPharm, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Department of Public Health, Section of Biostatistics, University of Copenhagen, Copenhagen, Denmark
| | - Melanie Ganz
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Department of Computer Science, University of Copenhagen, Copenhagen, Denmark
| | - Vibe G Frokjaer
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,NeuroPharm, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Psychiatric Center Copenhagen, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Vibeke Nh Dam
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,NeuroPharm, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Brenda Wjh Penninx
- BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Amsterdam UMC, Vrije Universiteit, Psychiatry, Amsterdam Public Health Research Institute, Amsterdam, The Netherlands
| | - Anajli Sankar
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Kamilla Miskowiak
- BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Copenhagen Affective Disorder Research Centre (CADIC), Psychiatric Centre Copenhagen, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark.,Department of Psychology, University of Copenhagen, Copenhagen, Denmark
| | - Peter S Jensen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,NeuroPharm, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,NeuroPharm, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Martin B Jorgensen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,NeuroPharm, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,BrainDrugs, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Psychiatric Center Copenhagen, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark
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6
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Voisin DA, Wakeford A, Nye J, Mun J, Jones SR, Locke J, Huhman KL, Wilson ME, Albers HE, Michopoulos V. Sex and social status modify the effects of fluoxetine on socioemotional behaviors in Syrian hamsters and rhesus macaques. Pharmacol Biochem Behav 2022; 215:173362. [PMID: 35219757 PMCID: PMC8983589 DOI: 10.1016/j.pbb.2022.173362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 01/31/2022] [Accepted: 02/20/2022] [Indexed: 11/18/2022]
Abstract
Social subordination increases risk for psychiatric disorders, while dominance increases resilience to these disorders. Fluoxetine, a selective serotonin (5HT) reuptake inhibitor whose actions are mediated in part by the 5HT1A receptor (5HT1AR), has sex- and social status-specific effects on socioemotional behavior and aggressive behavior. However, the impact of social status on these sex-specific effects remains unclear. The current study evaluated the impact of acute fluoxetine treatment and social status on dominance-related behaviors in female and male hamsters, and the impact of chronic fluoxetine treatment on socioemotional behavior and 5HT1AR binding potential (5HT1ARBP) in female rhesus macaques. We hypothesized that sex differences in the effects of fluoxetine on aggression in hamsters would be diminished in dominant and enhanced in subordinate males and that aggression in female hamsters would be enhanced in dominants and diminished in subordinates. In female rhesus macaques, we hypothesized that chronic fluoxetine would alter socioemotional behaviors and site-specific 5HT1ARBP in a status-dependent manner. Male (n = 46) and female (n = 56) hamsters were paired with conspecifics for three days to establish social rank. Hamsters received a single dose of 20 mg/kg fluoxetine or vehicle two-hours prior to a test with a non-aggressive intruder. Female rhesus monkeys (n = 14) housed were administered fluoxetine (2.8 mg/kg/day) or vehicle injections chronically for 14-days, separated by a three-week washout period. On Day 15, positron emission tomography neuroimaging for 5HT1ARBP was conducted. Fluoxetine treatment decreased aggression in subordinate female monkeys and subordinate female hamsters but not in dominant females of either species. Fluoxetine decreased aggression in dominant but not in subordinate male hamsters. Fluoxetine also reduced and increased prefrontal 5HT1ARBP in dominant and subordinate females, respectively. Taken together, these results provide cross-species evidence that social status and sex impact how increased 5HT modulates agonistic behavior.
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Affiliation(s)
- Dené A Voisin
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States of America; Center for Behavioral Neuroscience, Atlanta, GA, United States of America
| | - Alison Wakeford
- Yerkes National Primate Research Center, Atlanta, GA, United States of America
| | - Jonathon Nye
- Yerkes National Primate Research Center, Atlanta, GA, United States of America; Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States of America
| | - Jiyoung Mun
- Yerkes National Primate Research Center, Atlanta, GA, United States of America; Molecular Imaging Department, Charles River Laboratories, Mattawan, MI, United States of America
| | - Sara R Jones
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, United States of America
| | - Jason Locke
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, United States of America
| | - Kim L Huhman
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States of America; Center for Behavioral Neuroscience, Atlanta, GA, United States of America
| | - Mark E Wilson
- Yerkes National Primate Research Center, Atlanta, GA, United States of America; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States of America
| | - H Elliott Albers
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States of America; Center for Behavioral Neuroscience, Atlanta, GA, United States of America
| | - Vasiliki Michopoulos
- Yerkes National Primate Research Center, Atlanta, GA, United States of America; Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States of America.
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7
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Psychological mechanisms and functions of 5-HT and SSRIs in potential therapeutic change: Lessons from the serotonergic modulation of action selection, learning, affect, and social cognition. Neurosci Biobehav Rev 2020; 119:138-167. [PMID: 32931805 DOI: 10.1016/j.neubiorev.2020.09.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 08/31/2020] [Accepted: 09/03/2020] [Indexed: 12/14/2022]
Abstract
Uncertainty regarding which psychological mechanisms are fundamental in mediating SSRI treatment outcomes and wide-ranging variability in their efficacy has raised more questions than it has solved. Since subjective mood states are an abstract scientific construct, only available through self-report in humans, and likely involving input from multiple top-down and bottom-up signals, it has been difficult to model at what level SSRIs interact with this process. Converging translational evidence indicates a role for serotonin in modulating context-dependent parameters of action selection, affect, and social cognition; and concurrently supporting learning mechanisms, which promote adaptability and behavioural flexibility. We examine the theoretical basis, ecological validity, and interaction of these constructs and how they may or may not exert a clinical benefit. Specifically, we bridge crucial gaps between disparate lines of research, particularly findings from animal models and human clinical trials, which often seem to present irreconcilable differences. In determining how SSRIs exert their effects, our approach examines the endogenous functions of 5-HT neurons, how 5-HT manipulations affect behaviour in different contexts, and how their therapeutic effects may be exerted in humans - which may illuminate issues of translational models, hierarchical mechanisms, idiographic variables, and social cognition.
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8
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Mora S, Merchán A, Aznar S, Flores P, Moreno M. Increased amygdala and decreased hippocampus volume after schedule-induced polydipsia in high drinker compulsive rats. Behav Brain Res 2020; 390:112592. [PMID: 32417273 DOI: 10.1016/j.bbr.2020.112592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 02/04/2020] [Accepted: 02/25/2020] [Indexed: 02/08/2023]
Abstract
Fronto-limbic structures and serotonin 2A receptors (5-HT2A) have been implicated in the pathophysiology and treatment of compulsive spectrum disorders. Schedule-Induced Polydipsia (SIP), characterized by the development of excessive drinking under intermittent food reinforcement schedules, is a valid preclinical model for studying the compulsive phenotype. In the present study, we explored the individual differences and effect of SIP in brain volume and 5-HT2A receptor binding in fronto-limbic structures in rats selected according to their compulsive drinking behavior. Rats were divided into high (HD) and low drinkers (LD) by SIP (20 sessions); later, we analyzed the brains of HD and LD selected rats, in two different conditions: non-re-exposure (NRE) or re-exposure to SIP (RE), with four groups: LD-NRE, LD-RE, HD-NRE and HD-RE. Histological analyses were carried out for volumetric (stereology) and receptor binding (autoradiography) in the prelimbic and infralimbic cortex, dorsal hippocampus and basolateral amygdala. After SIP re-exposure, HD-RE showed an increased basolateral amygdala and a reduced hippocampus volume compared to HD-NRE rats, and also compared to LD-RE rats. No differences were found between HD and LD in NRE condition. Moreover, HD rats exhibit a lower 5-HT2A receptor binding in the basolateral amygdala, independently of SIP re-exposure, compared to LD rats. However, LD-RE showed a decreased 5-HT2A receptor binding in basolateral amygdala compared to LD-NRE. No differences were found in the remaining structures. These findings suggest that SIP might be differentially impacting HD and LD brains, pointing towards a possible explanation of how the latent vulnerability to compulsivity is triggered.
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Affiliation(s)
- Santiago Mora
- Department of Psychology & Health Research Centre (CEINSA), University of Almería, Almería, Spain
| | - Ana Merchán
- Department of Psychology & Health Research Centre (CEINSA), University of Almería, Almería, Spain
| | - Susana Aznar
- Research Laboratory for Stereology and Neuroscience, Bispebjerg-Frederiksberg University Hospital, Copenhagen, Denmark
| | - Pilar Flores
- Department of Psychology & Health Research Centre (CEINSA), University of Almería, Almería, Spain
| | - Margarita Moreno
- Department of Psychology & Health Research Centre (CEINSA), University of Almería, Almería, Spain.
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9
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Sander CY, Hansen HD, Wey HY. Advances in simultaneous PET/MR for imaging neuroreceptor function. J Cereb Blood Flow Metab 2020; 40:1148-1166. [PMID: 32169011 PMCID: PMC7238372 DOI: 10.1177/0271678x20910038] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Hybrid imaging using PET/MRI has emerged as a platform for elucidating novel neurobiology, molecular and functional changes in disease, and responses to physiological or pharmacological interventions. For the central nervous system, PET/MRI has provided insights into biochemical processes, linking selective molecular targets and distributed brain function. This review highlights several examples that leverage the strengths of simultaneous PET/MRI, which includes measuring the perturbation of multi-modal imaging signals on dynamic timescales during pharmacological challenges, physiological interventions or behavioral tasks. We discuss important considerations for the experimental design of dynamic PET/MRI studies and data analysis approaches for comparing and quantifying simultaneous PET/MRI data. The primary focus of this review is on functional PET/MRI studies of neurotransmitter and receptor systems, with an emphasis on the dopamine, opioid, serotonin and glutamate systems as molecular neuromodulators. In this context, we provide an overview of studies that employ interventions to alter the activity of neuroreceptors or the release of neurotransmitters. Overall, we emphasize how the synergistic use of simultaneous PET/MRI with appropriate study design and interventions has the potential to expand our knowledge about the molecular and functional dynamics of the living human brain. Finally, we give an outlook on the future opportunities for simultaneous PET/MRI.
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Affiliation(s)
- Christin Y Sander
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, MA, USA
| | - Hanne D Hansen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, MA, USA.,Neurobiology Research Unit and NeuroPharm, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Hsiao-Ying Wey
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, MA, USA
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Madsen MK, Fisher PM, Stenbæk DS, Kristiansen S, Burmester D, Lehel S, Páleníček T, Kuchař M, Svarer C, Ozenne B, Knudsen GM. A single psilocybin dose is associated with long-term increased mindfulness, preceded by a proportional change in neocortical 5-HT2A receptor binding. Eur Neuropsychopharmacol 2020; 33:71-80. [PMID: 32146028 DOI: 10.1016/j.euroneuro.2020.02.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 02/03/2020] [Accepted: 02/17/2020] [Indexed: 12/19/2022]
Abstract
A single dose of the serotonin 2A receptor (5-HT2AR) agonist psilocybin can have long-lasting beneficial effects on mood, personality, and potentially on mindfulness, but underlying mechanisms are unknown. Here, we for the first time conduct a study that assesses psilocybin effects on cerebral 5-HT2AR binding with [11C]Cimbi-36 positron emission tomography (PET) imaging and on personality and mindfulness. Ten healthy and psychedelic-naïve volunteers underwent PET neuroimaging of 5-HT2AR at baseline (BL) and one week (1W) after a single oral dose of psilocybin (0.2-0.3 mg/kg). Personality (NEO PI-R) and mindfulness (MAAS) questionnaires were completed at BL and at three-months follow-up (3M). Paired t-tests revealed statistically significant increases in personality Openness (puncorrected = 0.04, mean change [95%CI]: 4.2[0.4;∞]), which was hypothesized a priori to increase, and mindfulness (pFWER = 0.02, mean change [95%CI]: 0.5 [0.2;0.7]). Although 5-HT2AR binding at 1W versus BL was similar across individuals (puncorrected = 0.8, mean change [95%CI]: 0.007 [-0.04;0.06]), a post hoc linear regression analysis showed that change in mindfulness and 5-HT2AR correlated negatively (β [95%CI] = -5.0 [-9.0; -0.9], pFWER= 0.046). In conclusion, we confirm that psilocybin intake is associated with long-term increases in Openness and - as a novel finding - mindfulness, which may be a key element of psilocybin therapy. Cerebral 5-HT2AR binding did not change across individuals but the negative association between changes in 5-HT2AR binding and mindfulness suggests that individual change in 5-HT2AR levels after psilocybin is variable and represents a potential mechanism influencing long-term effects of psilocybin on mindfulness.
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Affiliation(s)
- Martin Korsbak Madsen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, 2100 Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Patrick MacDonald Fisher
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, 2100 Copenhagen, Denmark
| | - Dea Siggaard Stenbæk
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, 2100 Copenhagen, Denmark
| | - Sara Kristiansen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, 2100 Copenhagen, Denmark
| | - Daniel Burmester
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, 2100 Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Szabolcs Lehel
- PET and Cyclotron Unit, Copenhagen University Hospital Rigshospitalet, 2100 Copenhagen, Denmark
| | - Tomas Páleníček
- National Institute of Mental Health, 250 67 Klecany, Czech Republic
| | - Martin Kuchař
- National Institute of Mental Health, 250 67 Klecany, Czech Republic; Forensic Laboratory of Biologically Active Substances, Department of Chemistry of Natural Compounds, University of Chemistry and Technology, 166 28 Prague, Czech Republic
| | - Claus Svarer
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, 2100 Copenhagen, Denmark
| | - Brice Ozenne
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, 2100 Copenhagen, Denmark; Section of Biostatistics, Department of Public Health, University of Copenhagen, Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital Rigshospitalet, 2100 Copenhagen, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark.
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Tulver K, Bachmann M, Vaht M, Harro J, Bachmann T. Effects of HTR1A rs6295 polymorphism on emotional attentional blink. Acta Neurobiol Exp (Wars) 2020. [DOI: 10.21307/ane-2020-036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Insula serotonin 2A receptor binding and gene expression contribute to serotonin transporter polymorphism anxious phenotype in primates. Proc Natl Acad Sci U S A 2019; 116:14761-14768. [PMID: 31266890 PMCID: PMC6642374 DOI: 10.1073/pnas.1902087116] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Genetic variation in the serotonin transporter gene (SLC6A4) is associated with vulnerability to affective disorders and pharmacotherapy efficacy. We recently identified sequence polymorphisms in the common marmoset SLC6A4 repeat region (AC/C/G and CT/T/C) associated with individual differences in anxiety-like trait, gene expression, and response to antidepressants. The mechanisms underlying the effects of these polymorphisms are unknown, but a key mediator of serotonin action is the serotonin 2A receptor (5HT2A). Thus, we correlated 5HT2A binding potential (BP) and RNA gene expression in 16 SLC6A4 genotyped marmosets with responsivity to 5HT2A antagonism during the human intruder test of anxiety. Voxel-based analysis and RNA measurements showed a reduction in 5HT2A BP and gene expression specifically in the right posterior insula of individuals homozygous for the anxiety-related variant AC/C/G. These same marmosets displayed an anxiogenic, dose-dependent response to the human intruder after 5HT2A pharmacological antagonism, while CT/T/C individuals showed no effect. A voxel-based correlation analysis, independent of SLC6A4 genotype, revealed that 5HT2A BP in the adjacent right anterior insula and insula proisocortex was negatively correlated with trait anxiety scores. Moreover, 5HT2A BP in both regions was a good predictor of the size and direction of the acute emotional response to the human intruder threat after 5HT2A antagonism. Our findings suggest that genetic variation in the SLC6A4 repeat region may contribute to the trait anxious phenotype via neurochemical changes in brain areas implicated in interoceptive and emotional processing, with a critical role for the right insula 5HT2A in the regulation of affective responses to threat.
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Grimm O, Kraehenmann R, Preller KH, Seifritz E, Vollenweider FX. Psilocybin modulates functional connectivity of the amygdala during emotional face discrimination. Eur Neuropsychopharmacol 2018; 28:691-700. [PMID: 29703645 DOI: 10.1016/j.euroneuro.2018.03.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 12/28/2017] [Accepted: 03/22/2018] [Indexed: 11/26/2022]
Abstract
Recent studies suggest that the antidepressant effects of the psychedelic 5-HT2A receptor agonist psilocybin are mediated through its modulatory properties on prefrontal and limbic brain regions including the amygdala. To further investigate the effects of psilocybin on emotion processing networks, we studied for the first-time psilocybin's acute effects on amygdala seed-to-voxel connectivity in an event-related face discrimination task in 18 healthy volunteers who received psilocybin and placebo in a double-blind balanced cross-over design. The amygdala has been implicated as a salience detector especially involved in the immediate response to emotional face content. We used beta-series amygdala seed-to-voxel connectivity during an emotional face discrimination task to elucidate the connectivity pattern of the amygdala over the entire brain. When we compared psilocybin to placebo, an increase in reaction time for all three categories of affective stimuli was found. Psilocybin decreased the connectivity between amygdala and the striatum during angry face discrimination. During happy face discrimination, the connectivity between the amygdala and the frontal pole was decreased. No effect was seen during discrimination of fearful faces. Thus, we show psilocybin's effect as a modulator of major connectivity hubs of the amygdala. Psilocybin decreases the connectivity between important nodes linked to emotion processing like the frontal pole or the striatum. Future studies are needed to clarify whether connectivity changes predict therapeutic effects in psychiatric patients.
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Affiliation(s)
- O Grimm
- University Hospital Frankfurt, Departement of Psychiatry, Psychosomatics and Psychotherapy, Frankfurt am Main, Germany; Psychiatric Hospital Zürich, Department of Psychiatry, Psychotherapy and Psychosomatics, Zürich, Switzerland.
| | - R Kraehenmann
- Psychiatric Hospital Zürich, Department of Psychiatry, Psychotherapy and Psychosomatics, Zürich, Switzerland
| | - K H Preller
- Psychiatric Hospital Zürich, Department of Psychiatry, Psychotherapy and Psychosomatics, Zürich, Switzerland
| | - E Seifritz
- Psychiatric Hospital Zürich, Department of Psychiatry, Psychotherapy and Psychosomatics, Zürich, Switzerland
| | - F X Vollenweider
- Psychiatric Hospital Zürich, Department of Psychiatry, Psychotherapy and Psychosomatics, Zürich, Switzerland
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Selvaraj S, Walker C, Arnone D, Cao B, Faulkner P, Cowen PJ, Roiser JP, Howes O. Effect of Citalopram on Emotion Processing in Humans: A Combined 5-HT 1A [ 11C]CUMI-101 PET and Functional MRI Study. Neuropsychopharmacology 2018; 43:655-664. [PMID: 28776580 PMCID: PMC5693328 DOI: 10.1038/npp.2017.166] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 07/18/2017] [Accepted: 08/01/2017] [Indexed: 12/21/2022]
Abstract
A subset of patients started on a selective serotonin reuptake inhibitor (SSRI) initially experience increased anxiety, which can lead to early discontinuation before therapeutic effects are manifest. The neural basis of this early SSRI effect is not known. Presynaptic dorsal raphe neuron (DRN) 5-HT1A receptors are known to have a critical role in affect processing. Thus we investigated the effect of acute citalopram on emotional processing and the relationship between DRN 5-HT1A receptor availability and amygdala reactivity. Thirteen (mean age 48±9 years) healthy male subjects received either a saline or citalopram infusion intravenously (10 mg over 30 min) on separate occasions in a single-blind, random order, crossover design. On each occasion, participants underwent a block design face-emotion processing task during fMRI known to activate the amygdala. Ten subjects also completed a positron emission tomography (PET) scan to quantify DRN 5-HT1A availability using [11C]CUMI-101. Citalopram infusion when compared with saline resulted in a significantly increased bilateral amygdala responses to fearful vs neutral faces (left p=0.025; right p=0.038 FWE-corrected). DRN [11C]CUMI-101 availability significantly positively correlated with the effect of citalopram on the left amygdala response to fearful faces (Z=2.51, p=0.027) and right amygdala response to happy faces (Z=2.33, p=0.032). Our findings indicate that the initial effect of SSRI treatment is to alter processing of aversive stimuli and that this is linked to DRN 5-HT1A receptors in line with evidence that 5-HT1A receptors have a role in mediating emotional processing.
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Affiliation(s)
- Sudhakar Selvaraj
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA,Medical Research Council London Institute of Medical Sciences, Hammersmith Hospital, London, UK,Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston, Biomedical and Behavioral Sciences Building (BBSB), 1941 East Road, Suite 3208 Houston, TX 77054, USA, Tel: +1 713 486 2500, Fax: +1 713 486 2553, E-mail:
| | - Chris Walker
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Danilo Arnone
- Institute of Psychiatry, King’s College London, Centre for Affective Disorders, London, UK,IoPPN, King’s College London, Institute of Psychiatry, Psychosis Studies, London, UK
| | - Bo Cao
- Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Paul Faulkner
- Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, USA
| | - Philip J Cowen
- Department of Psychiatry, University of Oxford, Oxford, UK
| | - Jonathan P Roiser
- Institute of Cognitive Neuroscience, University College London, London, UK
| | - Oliver Howes
- Medical Research Council London Institute of Medical Sciences, Hammersmith Hospital, London, UK,IoPPN, King’s College London, Institute of Psychiatry, Psychosis Studies, London, UK,Institute of Clinical Sciences, Imperial College, Hammersmith Hospital, London, UK
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15
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da Cunha-Bang S, Hjordt LV, Dam VH, Stenbæk DS, Sestoft D, Knudsen GM. Anterior cingulate serotonin 1B receptor binding is associated with emotional response inhibition. J Psychiatr Res 2017; 92:199-204. [PMID: 28502766 DOI: 10.1016/j.jpsychires.2017.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 05/02/2017] [Accepted: 05/05/2017] [Indexed: 01/10/2023]
Abstract
Serotonin has a well-established role in emotional processing and is a key neurotransmitter in impulsive aggression, presumably by facilitating response inhibition and regulating subcortical reactivity to aversive stimuli. In this study 44 men, of whom 19 were violent offenders and 25 were non-offender controls, completed an emotional Go/NoGo task requiring inhibition of prepotent motor responses to emotional facial expressions. We also measured cerebral serotonin 1B receptor (5-HT1BR) binding with [11C]AZ10419369 positron emission tomography within regions of the frontal cortex. We hypothesized that 5-HT1BR would be positively associated with false alarms (failures to inhibit nogo responses) in the context of aversive (angry and fearful) facial expressions. Across groups, we found that frontal cortex 5-HT1BR binding was positively correlated with false alarms when angry faces were go stimuli and neutral faces were nogo stimuli (p = 0.05, corrected alpha = 0.0125), but not with false alarms for non-emotional stimuli (failures to inhibit geometric figures). A posthoc analysis revealed the strongest association in anterior cingulate cortex (p = 0.006). In summary, 5-HT1BRs in the anterior cingulate are involved in withholding a prepotent response in the context of angry faces. Our findings suggest that serotonin modulates response inhibition in the context of certain emotional stimuli.
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Affiliation(s)
- Sofi da Cunha-Bang
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Denmark
| | - Liv Vadskjær Hjordt
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Vibeke Høyrup Dam
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark
| | - Dea Siggaard Stenbæk
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Denmark
| | - Dorte Sestoft
- Ministry of Justice, Clinic of Forensic Psychiatry, Blegdamsvej 6B, DK-2200 Copenhagen, Denmark
| | - Gitte M Knudsen
- Neurobiology Research Unit, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100, Denmark; Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen, Denmark.
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16
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Involvement of serotonin 2A receptor activation in modulating medial prefrontal cortex and amygdala neuronal activation during novelty-exposure. Behav Brain Res 2017; 326:1-12. [PMID: 28263831 DOI: 10.1016/j.bbr.2017.02.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/23/2017] [Accepted: 02/28/2017] [Indexed: 12/11/2022]
Abstract
The medial prefrontal cortex (PFC) plays a major role in executive function by exerting a top-down control onto subcortical areas. Novelty-induced frontal cortex activation is 5-HT2A receptor (5-HT2AR) dependent. Here, we further investigated how blockade of 5-HT2ARs in mice exposed to a novel open-field arena affects medial PFC activation and basolateral amygdala (BLA) reactivity. We used c-Fos immunoreactivity (IR) as a marker of neuronal activation and stereological quantification for obtaining the total number of c-Fos-IR neurons as a measure of regional activation. We further examined the impact of 5-HT2AR blockade on the striatal-projecting BLA neurons. Systemic administration of ketanserin (0.5mg/kg) prior to novel open-field exposure resulted in reduced total numbers of c-Fos-IR cells in dorsomedial PFC areas and the BLA. Moreover, there was a positive correlation between the relative time spent in the centre of the open-field and BLA c-Fos-IR in the ketanserin-treated animals. Unilateral medial PFC lesions blocked this effect, ascertaining an involvement of this frontal cortex area. On the other hand, medial PFC lesioning exacerbated the more anxiogenic-like behaviour of the ketanserin-treated animals, upholding its involvement in modulating averseness. Ketanserin did not affect the number of activated striatal-projecting BLA neurons (measured by number of Cholera Toxin b (CTb) retrograde labelled neurons also being c-Fos-IR) following CTb injection in the ventral striatum. These results support a role of 5-HT2AR activation in modulating mPFC and BLA activation during exposure to a novel environment, which may be interrelated. Conversely, 5-HT2AR blockade does not seem to affect the amygdala-striatal projection.
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17
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Raab K, Kirsch P, Mier D. Understanding the impact of 5-HTTLPR, antidepressants, and acute tryptophan depletion on brain activation during facial emotion processing: A review of the imaging literature. Neurosci Biobehav Rev 2016; 71:176-197. [DOI: 10.1016/j.neubiorev.2016.08.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Revised: 07/28/2016] [Accepted: 08/26/2016] [Indexed: 12/22/2022]
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18
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Dressler WW, Balieiro MC, Ferreira de Araújo L, Silva WA, Ernesto Dos Santos J. Culture as a mediator of gene-environment interaction: Cultural consonance, childhood adversity, a 2A serotonin receptor polymorphism, and depression in urban Brazil. Soc Sci Med 2016; 161:109-17. [PMID: 27270123 DOI: 10.1016/j.socscimed.2016.05.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 05/18/2016] [Accepted: 05/20/2016] [Indexed: 12/14/2022]
Abstract
Research on gene-environment interaction was facilitated by breakthroughs in molecular biology in the late 20th century, especially in the study of mental health. There is a reliable interaction between candidate genes for depression and childhood adversity in relation to mental health outcomes. The aim of this paper is to explore the role of culture in this process in an urban community in Brazil. The specific cultural factor examined is cultural consonance, or the degree to which individuals are able to successfully incorporate salient cultural models into their own beliefs and behaviors. It was hypothesized that cultural consonance in family life would mediate the interaction of genotype and childhood adversity. In a study of 402 adult Brazilians from diverse socioeconomic backgrounds, conducted from 2011 to 2014, the interaction of reported childhood adversity and a polymorphism in the 2A serotonin receptor was associated with higher depressive symptoms. Further analysis showed that the gene-environment interaction was mediated by cultural consonance in family life, and that these effects were more pronounced in lower social class neighborhoods. The findings reinforce the role of the serotonergic system in the regulation of stress response and learning and memory, and how these processes in turn interact with environmental events and circumstances. Furthermore, these results suggest that gene-environment interaction models should incorporate a wider range of environmental experience and more complex pathways to better understand how genes and the environment combine to influence mental health outcomes.
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Affiliation(s)
- William W Dressler
- Department of Anthropology, The University of Alabama, Tuscaloosa, AL, United States.
| | - Mauro C Balieiro
- Department of Psychology, Paulista University, Ribeirao Preto, Brazil
| | - Luiza Ferreira de Araújo
- Department of Genetics, Ribeirao Preto Medical School, University of Sao Paulo-Ribeirao Preto, Brazil; Center for Medical Genomics at HCFMRP/USP, Brazil
| | - Wilson A Silva
- Department of Genetics, Ribeirao Preto Medical School, University of Sao Paulo-Ribeirao Preto, Brazil; Center for Medical Genomics at HCFMRP/USP, Brazil
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Mills M, Wieda O, Stoltenberg SF, Dodd MD. Emotion moderates the association between HTR2A (rs6313) genotype and antisaccade latency. Exp Brain Res 2016; 234:2653-65. [PMID: 27161551 DOI: 10.1007/s00221-016-4669-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 04/29/2016] [Indexed: 10/21/2022]
Abstract
The serotonin system is heavily involved in cognitive and emotional control processes. Previous work has typically investigated this system's role in control processes separately for cognitive and emotional domains, yet it has become clear the two are linked. The present study, therefore, examined whether variation in a serotonin receptor gene (HTR2A, rs6313) moderated effects of emotion on inhibitory control. An emotional antisaccade task was used in which participants looked toward (prosaccade) or away (antisaccade) from a target presented to the left or right of a happy, angry, or neutral face. Overall, antisaccade latencies were slower for rs6313 C allele homozygotes than T allele carriers, with no effect of genotype on prosaccade latencies. Thus, C allele homozygotes showed relatively weak inhibitory control but intact reflexive control. Importantly, the emotional stimulus was either present during target presentation (overlap trials) or absent (gap trials). The gap effect (slowed latency in overlap versus gap trials) in antisaccade trials was larger with angry versus neutral faces in C allele homozygotes. This impairing effect of negative valence on inhibitory control was larger in C allele homozygotes than T allele carriers, suggesting that angry faces disrupted/competed with the control processes needed to generate an antisaccade to a greater degree in these individuals. The genotype difference in the negative valence effect on antisaccade latency was attenuated when trial N-1 was an antisaccade, indicating top-down regulation of emotional influence. This effect was reduced in C/C versus T/_ individuals, suggesting a weaker capacity to downregulate emotional processing of task-irrelevant stimuli.
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Affiliation(s)
- Mark Mills
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588, USA.
| | - Olivia Wieda
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588, USA
| | - Scott F Stoltenberg
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588, USA
| | - Michael D Dodd
- Department of Psychology, University of Nebraska-Lincoln, 238 Burnett Hall, Lincoln, NE, 68588, USA
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Aznar S, Hervig MES. The 5-HT2A serotonin receptor in executive function: Implications for neuropsychiatric and neurodegenerative diseases. Neurosci Biobehav Rev 2016; 64:63-82. [DOI: 10.1016/j.neubiorev.2016.02.008] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 11/05/2015] [Accepted: 02/08/2016] [Indexed: 02/07/2023]
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Converse AK, Aubert Y, Allers KA, Sommer B, Abbott DH. Flibanserin-Stimulated Partner Grooming Reflects Brain Metabolism Changes in Female Marmosets. J Sex Med 2015; 12:2256-66. [PMID: 26635207 PMCID: PMC5681869 DOI: 10.1111/jsm.13068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Female sexual interest and arousal disorder is personally distressing for women. To better understand the mechanism of the candidate therapeutic, flibanserin, we determined its effects on an index of brain glucose metabolism. AIM We hypothesized that chronic treatment with flibanserin would alter metabolism in brain regions associated with serotonergic function and female sexual behavior. METHODS In a crossover design, eight adult female common marmosets (Calithrix jacchus) received daily flibanserin or vehicle. After 7-12 weeks of treatment, the glucose metabolism radiotracer [(18) F]fluorodeoxyglucose (FDG) was administered to each female immediately prior to 30 minutes of interaction with her male pairmate, after which females were anesthetized and imaged by positron emission tomography. Whole-brain normalized images were analyzed with anatomically defined regions of interest. Whole-brain voxelwise mapping was used to explore treatment effects. Correlations were examined between alterations in metabolism and pairmate social grooming. MAIN OUTCOME MEASURES Changes in metabolism associated with flibanserin were determined for dorsal raphe, medial prefrontal cortex (mPFC), medial preoptic area of hypothalamus (mPOA), ventromedial nucleus of hypothalamus, and field cornu ammonis 1 (CA1) of the hippocampus. RESULTS In response to chronic flibanserin, metabolism in mPOA declined, and this reduction correlated with increases in pairmate grooming. A cluster of voxels in frontal cortico-limbic regions exhibited reduced metabolism in response to flibanserin and overlapped with a voxel cluster in which reductions in metabolism correlated with increases in pairmate grooming. Finally, reductions in mPOA metabolism correlated with increases in metabolism in a cluster of voxels in somatosensory cortex. CONCLUSIONS Taken together, these results suggest that flibanserin-induced reductions in female mPOA neural activity increase intimate affiliative behavior with male pairmates.
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Affiliation(s)
| | - Yves Aubert
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, US
- Department of Biological and Medical Psychology, University of Bergen, NO
| | - Kelly A. Allers
- Department of CNS Diseases, Boehringer Ingelheim, Biberach, DE
| | - Bernd Sommer
- Department of CNS Diseases, Boehringer Ingelheim, Biberach, DE
| | - David H. Abbott
- Wisconsin National Primate Research Center, University of Wisconsin-Madison, US
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, US
- Endocrinology-Reproductive Physiology Training Program, University of Wisconsin-Madison, US
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Neuroticism and serotonin 5-HT1A receptors in healthy subjects. Psychiatry Res 2015; 234:1-6. [PMID: 26337006 DOI: 10.1016/j.pscychresns.2015.04.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/05/2015] [Accepted: 04/22/2015] [Indexed: 11/20/2022]
Abstract
Neuroticism is a personality trait associated with vulnerability for mood and anxiety disorders. Serotonergic mechanisms likely contribute to neuroticism. Serotonin 5-HT1A receptors are altered in mood and anxiety disorders, but whether 5-HT1A receptors are associated with neuroticism in healthy subjects is unclear. We measured brain serotonin 5-HT1A receptor in 34 healthy subjects in vivo using positron emission tomography (PET) and [carbonyl-(11)C]WAY-100635. Binding potential (BPP) was determined using the golden standard of kinetic compartmental modeling using arterial blood samples and radiometabolite determination. Personality traits were assessed using the Karolinska Scales of Personality. We found a strong negative association between serotonin 5-HT1A receptor BPP and neuroticism. That is, individuals with high neuroticism tended to have lower 5-HT1A receptor binding than individuals with low neuroticism. This finding was confirmed with an independent voxel-based whole-brain analysis. Other personality traits did not correlate with 5-HT1A receptor BPP. Previous observations have reported lower serotonin 5-HT1A receptor density in major depression. This neurobiological finding may be a trait-like phenomenon and partly explained by higher neuroticism in patients with affective disorders. The link between personality traits and 5-HT1A receptors should be studied in patients with major depression.
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Yildirim BO, Derksen JJL. Mesocorticolimbic dopamine functioning in primary psychopathy: A source of within-group heterogeneity. Psychiatry Res 2015; 229:633-77. [PMID: 26277034 DOI: 10.1016/j.psychres.2015.07.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 04/08/2015] [Accepted: 07/05/2015] [Indexed: 01/17/2023]
Abstract
Despite similar emotional deficiencies, primary psychopathic individuals can be situated on a continuum that spans from controlled to disinhibited. The constructs on which primary psychopaths are found to diverge, such as self-control, cognitive flexibility, and executive functioning, are crucially regulated by dopamine (DA). As such, the goal of this review is to examine which specific alterations in the meso-cortico-limbic DA system and corresponding genes (e.g., TH, DAT, COMT, DRD2, DRD4) might bias development towards a more controlled or disinhibited expression of primary psychopathy. Based on empirical data, it is argued that primary psychopathy is generally related to a higher tonic and population activity of striatal DA neurons and lower levels of D2-type DA receptors in meso-cortico-limbic projections, which may boost motivational drive towards incentive-laden goals, dampen punishment sensitivity, and increase future reward-expectancy. However, increasingly higher levels of DA activity in the striatum (moderate versus pathological elevations), lower levels of DA functionality in the prefrontal cortex, and higher D1-to-D2-type receptor ratios in meso-cortico-limbic projections may lead to increasingly disinhibited and impetuous phenotypes of primary psychopathy. Finally, in order to provide a more coherent view on etiological mechanisms, we discuss interactions between DA and serotonin that are relevant for primary psychopathy.
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Affiliation(s)
- Bariş O Yildirim
- Department of Clinical Psychology, Radboud University Nijmegen, De Kluyskamp 1002, 6545 JD Nijmegen, The Netherlands.
| | - Jan J L Derksen
- Department of Clinical Psychology, Room: A.07.04B, Radboud University Nijmegen, Montessorilaan 3, 6525 HR Nijmegen, The Netherlands.
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Selvaraj S, Mouchlianitis E, Faulkner P, Turkheimer F, Cowen PJ, Roiser JP, Howes O. Presynaptic Serotoninergic Regulation of Emotional Processing: A Multimodal Brain Imaging Study. Biol Psychiatry 2015; 78:563-571. [PMID: 24882568 PMCID: PMC5322825 DOI: 10.1016/j.biopsych.2014.04.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Revised: 04/01/2014] [Accepted: 04/01/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND The amygdala is a central node in the brain network that processes aversive emotions and is extensively innervated by dorsal raphe nucleus (DRN) serotonin (5-hydroxytryptamine [5-HT]) neurons. Alterations in DRN 5-HT1A receptor availability cause phenotypes characterized by fearful behavior in preclinical models. However, it is unknown whether 5-HT1A receptor availability is linked specifically to the processing of aversive emotions in humans or whether it modulates connectivity in brain networks involved in emotion processing. To answer this question, we investigated the relationship between DRN 5-HT1A receptor availability and amygdala reactivity to aversive emotion and functional connectivity within the amygdala-cortical network. METHODS We studied 15 healthy human participants who underwent positron emission tomography scanning with [(11)C]CUMI-101, a 5-HT1A partial agonist radioligand, and functional magnetic resonance imaging of brain responses during an incidental emotion processing task including happy, fearful, and neutral faces. Regional estimates of 5-HT1A receptor binding potential (nondisplaceable) were obtained by calculating total volumes of distribution for presynaptic DRN and amygdala. Connectivity between the amygdala and corticolimbic areas was assessed using psychophysiologic interaction analysis with the amygdala as the seed region. RESULTS Analysis of the fear versus neutral contrast revealed a significant negative correlation between amygdala response and DRN binding potential (nondisplaceable) (r = -.87, p < .001). Availability of DRN 5-HT1A receptors positively correlated with amygdala connectivity with middle frontal gyrus, anterior cingulate cortex, bilateral precuneus, and left supramarginal gyrus for fearful (relative to neutral) faces. CONCLUSIONS Our data show that DRN 5-HT1A receptor availability is linked specifically to the processing of aversive emotions in the amygdala and the modulation of amygdala-cortical connectivity.
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Affiliation(s)
- Sudhakar Selvaraj
- Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, London, W12 0NN, UK,Department of Psychiatry and Behavioral Sciences, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Elias Mouchlianitis
- Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, London, W12 0NN, UK
| | - Paul Faulkner
- Institute of Cognitive Neuroscience, University College London, WC1N 3AR, UK
| | | | | | - Jonathan P Roiser
- Institute of Cognitive Neuroscience, University College London, WC1N 3AR, UK
| | - Oliver Howes
- Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, London, W12 0NN, UK,Institute of Psychiatry, King’s College London, SE5 8AF, UK
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Challis C, Berton O. Top-Down Control of Serotonin Systems by the Prefrontal Cortex: A Path toward Restored Socioemotional Function in Depression. ACS Chem Neurosci 2015; 6:1040-54. [PMID: 25706226 DOI: 10.1021/acschemneuro.5b00007] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Social withdrawal, increased threat perception, and exaggerated reassurance seeking behaviors are prominent interpersonal symptoms in major depressive disorder (MDD). Altered serotonin (5-HT) systems and corticolimbic dysconnectivity have long been suspected to contribute to these symptomatic facets; however, the underlying circuits and intrinsic cellular mechanisms that control 5-HT output during socioemotional interactions remain poorly understood. We review literature that implicates a direct pathway between the ventromedial prefrontal cortex (vmPFC) and dorsal raphe nucleus (DRN) in the adaptive and pathological control of social approach-avoidance behaviors. Imaging and neuromodulation during approach-avoidance tasks in humans point to the cortical control of brainstem circuits as an essential regulator of socioemotional decisions and actions. Parallel rodent studies using viral-based connectomics and optogenetics are beginning to provide a cellular blueprint of the underlying circuitry. In these studies, manipulations of vmPFC synaptic inputs to the DRN have revealed bidirectional influences on socioaffective behaviors via direct monosynaptic excitation and indirect disynaptic inhibition of 5-HT neurons. Additionally, adverse social experiences that result in permanent avoidance biases, such as social defeat, drive long-lasting plasticity in this microcircuit, potentiating the indirect inhibition of 5-HT output. Conversely, neuromodulation of the vmPFC via deep brain stimulation (DBS) attenuates avoidance biases by restoring the direct excitatory drive of 5-HT neurons and strengthening a key subset of forebrain 5-HT projections. Better understanding the cellular organization of the vmPFC-DRN pathway and identifying molecular determinants of its neuroplasticity can open fundamentally novel avenues for the treatment of affective disorders.
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Affiliation(s)
- Collin Challis
- Department of Psychiatry, ‡Neuroscience Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, United States
| | - Olivier Berton
- Department of Psychiatry, ‡Neuroscience Graduate Group, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, United States
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Fluctuations in [¹¹C]SB207145 PET binding associated with change in threat-related amygdala reactivity in humans. Neuropsychopharmacology 2015; 40:1510-8. [PMID: 25560201 PMCID: PMC4397409 DOI: 10.1038/npp.2014.339] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 11/27/2014] [Accepted: 12/11/2014] [Indexed: 12/17/2022]
Abstract
Serotonin critically affects the neural processing of emotionally salient stimuli, including indices of threat; however, how alterations in serotonin signaling contribute to changes in brain function is not well understood. Recently, we showed in a placebo-controlled study of 32 healthy males that brain serotonin 4 receptor (5-HT4) binding, assessed with [(11)C]SB207145 PET, was sensitive to a 3-week intervention with the selective serotonin reuptake inhibitor fluoxetine, supporting it as an in vivo model for fluctuations in central serotonin levels. Participants also underwent functional magnetic resonance imaging while performing a gender discrimination task of fearful, angry, and neutral faces. This offered a unique opportunity to evaluate whether individual fluctuations in central serotonin levels, indexed by change in [(11)C]SB207145 binding, predicted changes in threat-related reactivity (ie, fear and angry vs neutral faces) within a corticolimbic circuit including the amygdala and medial prefrontal and anterior cingulate cortex. We observed a significant association such that decreased brain-wide [(11)C]SB207145 binding (ie, increased brain serotonin levels) was associated with lower threat-related amygdala reactivity, whereas intervention group status did not predict change in corticolimbic reactivity. This suggests that in the healthy brain, interindividual responses to pharmacologically induced and spontaneously occurring fluctuations in [(11)C]SB207145 binding, a putative marker of brain serotonin levels, affect amygdala reactivity to threat. Our finding also supports that change in brain [(11)C]SB207145 binding may be a relevant marker for evaluating neurobiological mechanisms underlying sensitivity to threat and serotonin signaling.
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Andolina D, Maran D, Viscomi MT, Puglisi-Allegra S. Strain-dependent variations in stress coping behavior are mediated by a 5-HT/GABA interaction within the prefrontal corticolimbic system. Int J Neuropsychopharmacol 2015; 18:pyu074. [PMID: 25522413 PMCID: PMC4360254 DOI: 10.1093/ijnp/pyu074] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND Serotonin and γ-aminobutyric acid (GABA) transmission is crucial in coping strategies. METHODS Here, using mice from 2 inbred strains widely exploited in behavioral neurochemistry, we investigated whether serotonin transmission in medial prefrontal cortex and GABA in basolateral amygdala determine strain-dependent liability to stress response and differences in coping. RESULTS C57BL/6J mice displayed greater immobility in the forced swimming test, higher serotonin outflow in medial prefrontal cortex, higher GABA outflow in basolateral amygdala induced by stress, and higher serotonin 1A receptor levels in medial prefrontal cortex accompanied by lower GABAb receptor levels in basolateral amygdala than DBA/2J mice. In assessing whether serotonin in medial prefrontal cortex determines GABA functioning in response to stress and passive coping behavior in C57BL/6J and DBA/2J mice, we observed that selective prefrontal serotonin depletion in C57BL/6J and DBA/2J reduced stress-induced GABA outflow in basolateral amygdala and immobility in the forced swimming test. CONCLUSIONS These results show that strain-dependent prefrontal corticolimbic serotonin/GABA regulation determines the strain differences in stress-coping behavior in the forced swimming test and point to a role of a specific neuronal system in genetic susceptibility to stress that opens up new prospects for innovative therapies for stress disorders.
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Affiliation(s)
- Diego Andolina
- Santa Lucia Foundation, Rome, Italy (Drs Andolina, Viscomi, and Puglisi-Allegra); Dipartimento di Scienze Cliniche Applicate e Biotecnologie, Universita` degli Studi dell'Aquila, Via Vetoio, L'Aquila, Italy (Dr Andolina); Dipartimento di Psicologia and Centro 'Daniel Bovet,' Sapienza Università di Roma, Rome, Italy (Drs Maran and Puglisi-Allegra).
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Sarkar A, Chachra P, Vaidya VA. Postnatal fluoxetine-evoked anxiety is prevented by concomitant 5-HT2A/C receptor blockade and mimicked by postnatal 5-HT2A/C receptor stimulation. Biol Psychiatry 2014; 76:858-68. [PMID: 24315410 DOI: 10.1016/j.biopsych.2013.11.005] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 11/01/2013] [Accepted: 11/01/2013] [Indexed: 11/25/2022]
Abstract
BACKGROUND Postnatal treatment with the selective serotonin reuptake inhibitor fluoxetine, evokes anxiety and depressive behavior in rodent models in adulthood. We examined the role of serotonin 2A (5-HT2A), serotonin 2C (5-HT2C) and serotonin 1A (5-HT1A) receptors, implicated in the development of anxiety, in the behavioral consequences of postnatal fluoxetine (PNFlx). METHODS Control and PNFlx rat pups received concomitant treatment with the 5-HT2A/C receptor antagonist, ketanserin, the 5-HT2A receptor antagonist, MDL100907, the 5-HT2C receptor antagonist, SB242084, or the 5-HT1A receptor antagonist, WAY-100635, and were tested for behavior in adulthood. The effect of postnatal treatment with the 5-HT2A/C receptor agonist, DOI, on anxiety behavior was examined in adulthood. RESULTS Postnatal 5-HT2A/C receptor blockade prevented PNFlx-evoked anxiety, attenuated depressive behavior, and normalized specific gene expression changes in the prefrontal cortex. Postnatal, selective 5-HT2A receptor antagonist treatment blocked PNFlx-evoked anxiety and depressive behavior, whereas 5-HT2C receptor antagonist treatment prevented anxiety but not depressive behavior. Postnatal 5-HT2A/C receptor stimulation was sufficient to evoke anxiety in adulthood. Serotonin 1A receptor blockade did not alter PNFlx-evoked anxiety but resulted in anxiety in control animals, an effect attenuated by concomitant 5-HT2A/C receptor blockade. CONCLUSIONS Postnatal fluoxetine-evoked anxiety and depressive behavior, as well as specific gene expression changes in the prefrontal cortex, were prevented by 5-HT2A/C receptor blockade. Adult anxiety was evoked by either 5-HT2A/C receptor stimulation or 5-HT1A receptor blockade of naive control pups. Our findings implicate serotonin 2 receptors in the development of perturbed emotionality following PNFlx and suggest that an altered balance of signaling through 5-HT1A and 5-HT2A/C receptors in early life influences anxiety behavior.
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Affiliation(s)
- Ambalika Sarkar
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Parul Chachra
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India
| | - Vidita A Vaidya
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, India.
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Wilson CB, McLaughlin LD, Ebenezer PJ, Nair AR, Dange R, Harre JG, Shaak TL, Diamond DM, Francis J. Differential effects of sertraline in a predator exposure animal model of post-traumatic stress disorder. Front Behav Neurosci 2014; 8:256. [PMID: 25126063 PMCID: PMC4115632 DOI: 10.3389/fnbeh.2014.00256] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 07/10/2014] [Indexed: 11/24/2022] Open
Abstract
Serotonin (5-HT), norepinephrine (NE), and other neurotransmitters are modulated in post-traumatic stress disorder (PTSD). In addition, pro-inflammatory cytokines (PIC) are elevated during the progression of the disorder. Currently, the only approved pharmacologic treatments for PTSD are the selective-serotonin reuptake inhibitors (SSRI) sertraline and paroxetine, but their efficacy in treating PTSD is marginal at best. In combat-related PTSD, SSRIs are of limited effectiveness. Thus, this study sought to analyze the effects of the SSRI sertraline on inflammation and neurotransmitter modulation via a predator exposure/psychosocial stress animal model of PTSD. We hypothesized that sertraline would diminish inflammatory components and increase 5-HT but might also affect levels of other neurotransmitters, particularly NE. PTSD-like effects were induced in male Sprague-Dawley rats (n = 6/group × 4 groups). The rats were secured in Plexiglas cylinders and placed in a cage with a cat for 1 h on days 1 and 11 of a 31-day stress regimen. PTSD rats were also subjected to psychosocial stress via daily cage cohort changes. At the conclusion of the stress regimen, treatment group animals were injected intraperitoneally (i.p.) with sertraline HCl at 10 mg/kg for 7 consecutive days, while controls received i.p. vehicle. The animals were subsequently sacrificed on day 8. Sertraline attenuated inflammatory markers and normalized 5-HT levels in the central nervous system (CNS). In contrast, sertraline produced elevations in NE in the CNS and systemic circulation of SSRI treated PTSD and control groups. This increase in NE suggests SSRIs produce a heightened noradrenergic response, which might elevate anxiety in a clinical setting.
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Affiliation(s)
- C Brad Wilson
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, LA, USA
| | - Leslie D McLaughlin
- Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, LA, USA
| | - Philip J Ebenezer
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, LA, USA
| | - Anand R Nair
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, LA, USA
| | - Rahul Dange
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, LA, USA
| | - Joseph G Harre
- Air Force Clinical Research Laboratory, Keesler Air Force Base MS, USA
| | - Thomas L Shaak
- Air Force Clinical Research Laboratory, Keesler Air Force Base MS, USA
| | - David M Diamond
- Medical Research Service, VA Hospital Tampa, FL, USA ; Departments of Psychology and Molecular Pharmacology and Physiology, Center for Preclinical and Clinical Research on PTSD, University of South Florida Tampa, FL, USA
| | - Joseph Francis
- Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University Baton Rouge, LA, USA
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Wilson CB, McLaughlin LD, Ebenezer PJ, Nair AR, Francis J. Valproic acid effects in the hippocampus and prefrontal cortex in an animal model of post-traumatic stress disorder. Behav Brain Res 2014; 268:72-80. [DOI: 10.1016/j.bbr.2014.03.029] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 03/08/2014] [Accepted: 03/10/2014] [Indexed: 12/31/2022]
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Wilson CB, Ebenezer PJ, McLaughlin LD, Francis J. Predator exposure/psychosocial stress animal model of post-traumatic stress disorder modulates neurotransmitters in the rat hippocampus and prefrontal cortex. PLoS One 2014; 9:e89104. [PMID: 24551226 PMCID: PMC3925189 DOI: 10.1371/journal.pone.0089104] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/20/2014] [Indexed: 12/31/2022] Open
Abstract
Post-Traumatic Stress Disorder (PTSD) can develop in response to a traumatic event involving a threat to life. To date, no diagnostic biomarkers have been identified for PTSD. Recent research points toward physiological abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis, sympathoadrenal medullary and immune system that may be implicated in the disorder. The modulation of neurotransmitters is another possible mechanism, but their role in the progression of PTSD is poorly understood. Low serotonin (5-HT) may be a factor, but it may not be the only neurotransmitter affected as modulation affects levels of other neurotransmitters. In this study, we hypothesized the predator exposure/psychosocial stress rodent model of PTSD may alter levels of 5-HT and other neurotransmitters in the rat hippocampus and prefrontal cortex (PFC). Male Sprague-Dawley rats were used in this experiment. We induced PTSD via a predator exposure/psychosocial stress model, whereby rats were placed in a cage with a cat for 1 hour on days 1 and 11 of the 31-day experiment. Rats also received psychosocial stress via daily cage cohort changes. On day 32, the rats were sacrificed and the brains dissected to remove the hippocampus and PFC. Norepinephrine (NE), 5-Hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), dopamine (DA), and 3,4-Dihydroxyphenylacetic acid (DOPAC), and 5-HT levels in the hippocampus and PFC were measured with high-performance liquid chromatography (HPLC). In the hippocampus, 5-HT and HVA were lower, while NE and DOPAC were higher, in the PTSD group vs. controls. In the PFC, only 5-HT was lower, while NE, DA, and DOPAC were higher, in the PTSD group vs. controls. The rate limiting enzymes tyrosine hydroxylase and tryptophan hydroxylase were also examined and confirmed our findings. These results demonstrate that the predator exposure/psychosocial stress model of PTSD produces neurotransmitter changes similar to those seen in human patients and may cause a heightened noradrenergic response.
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Affiliation(s)
- C. Brad Wilson
- Comparative Biomedical Sciences, Louisiana State University, School of Veterinary Medicine, Baton Rouge, Louisiana, United States of America
| | - Philip J. Ebenezer
- Comparative Biomedical Sciences, Louisiana State University, School of Veterinary Medicine, Baton Rouge, Louisiana, United States of America
| | - Leslie D. McLaughlin
- Pathobiological Sciences, Louisiana State University, School of Veterinary Medicine, Baton Rouge, Louisiana, United States of America
- * E-mail: (LDM); (JF)
| | - Joseph Francis
- Comparative Biomedical Sciences, Louisiana State University, School of Veterinary Medicine, Baton Rouge, Louisiana, United States of America
- * E-mail: (LDM); (JF)
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Michopoulos V, Diaz MP, Embree M, Reding K, Votaw JR, Mun J, Voll RJ, Goodman MM, Wilson M, Sanchez M, Toufexis D. Oestradiol alters central 5-HT1A receptor binding potential differences related to psychosocial stress but not differences related to 5-HTTLPR genotype in female rhesus monkeys. J Neuroendocrinol 2014; 26:80-8. [PMID: 24382202 PMCID: PMC3962807 DOI: 10.1111/jne.12129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 12/23/2013] [Indexed: 12/12/2022]
Abstract
Social subordination in female macaques represents a well-described model of chronic psychosocial stress. Additionally, a length polymorphism (5-HTTLPR) in the regulatory region of the serotonin (5-HT) transporter (5-HTT) gene (SLC6A4) is present in rhesus macaques, which has been linked to adverse outcomes similar to that described in humans with an analogous 5-HTTLPR polymorphism. The present study determined the effects of social status and the 5-HTTLPR genotype on 5-HT1A receptor binding potential (5-HT1A BP(ND)) in brain regions implicated in emotional regulation and stress reactivity in ovariectomised female monkeys, and then assessed how these effects were altered by 17β-oestradiol (E(2)) treatment. Areas analysed included the prefrontal cortex [anterior cingulate (ACC); medial prefrontal cortex (mPFC); dorsolateral prefrontal cortex; orbitofrontal prefrontal cortex], amygdala, hippocampus, hypothalamus and raphe nucleui. Positron emission tomography using p-[(18) F]MPPF was performed to determine the levels of 5-HT1A BP(ND) under a non-E(2) and a 3-week E(2) treatment condition. The short variant (s-variant) 5-HTTLPR genotype produced a significant reduction in 5-HT1A BP(ND) in the mPFC regardless of social status, and subordinate s-variant females showed a reduction in 5-HT1A BP(ND) within the ACC. Both these effects of 5-HTTLPR were unaffected by E(2). Additionally, E(2) reduced 5-HT1A BP(ND) in the dorsal raphe of all females irrespective of psychosocial stress or 5-HTTLPR genotype. Hippocampal 5-HT1A BP(ND) was attenuated in subordinate females regardless of 5-HTTLPR genotype during the non-E(2) condition, an effect that was normalised with E(2). Similarly, 5-HT1A BP(ND) in the hypothalamus was significantly lower in subordinate females regardless of 5-HTTLPR genotype, an effect reversed with E(2). Taken together, the data indicate that the effect of E(2) on modulation of central 5HT1A BP(ND) may only occur in brain regions that show no 5-HTTLPR genotype-linked control of 5-HT1A binding.
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Affiliation(s)
- Vasiliki Michopoulos
- Division of Developmental & Cognitive Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, GA
- Department of Psychiatry & Behavioural Sciences, Emory University SOM, Atlanta, GA
| | - Maylen Perez Diaz
- Division of Developmental & Cognitive Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, GA
| | - Molly Embree
- Division of Developmental & Cognitive Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, GA
| | - Kathy Reding
- Division of Developmental & Cognitive Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, GA
| | - John R. Votaw
- Department of Radiology and Imaging Sciences, School of Medicine, Emory University, Atlanta, GA, USA
- Imaging Core, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Jiyoung Mun
- Department of Radiology and Imaging Sciences, School of Medicine, Emory University, Atlanta, GA, USA
- Imaging Core, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Ronald J. Voll
- Department of Radiology and Imaging Sciences, School of Medicine, Emory University, Atlanta, GA, USA
- Imaging Core, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Mark M. Goodman
- Division of Developmental & Cognitive Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, GA
- Department of Radiology and Imaging Sciences, School of Medicine, Emory University, Atlanta, GA, USA
- Imaging Core, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA
| | - Mark Wilson
- Division of Developmental & Cognitive Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, GA
| | - Mar Sanchez
- Division of Developmental & Cognitive Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, GA
- Department of Psychiatry & Behavioural Sciences, Emory University SOM, Atlanta, GA
| | - Donna Toufexis
- Division of Developmental & Cognitive Neuroscience, Yerkes National Primate Research Center, Emory University, Atlanta, GA
- Department of Psychology, University of Vermont, Burlington VT
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Acute effects of Sceletium tortuosum (Zembrin), a dual 5-HT reuptake and PDE4 inhibitor, in the human amygdala and its connection to the hypothalamus. Neuropsychopharmacology 2013; 38:2708-16. [PMID: 23903032 PMCID: PMC3828542 DOI: 10.1038/npp.2013.183] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 07/22/2013] [Accepted: 07/22/2013] [Indexed: 01/31/2023]
Abstract
The South African endemic plant Sceletium tortuosum has a long history of traditional use as a masticatory and medicine by San and Khoikhoi people and subsequently by European colonial farmers as a psychotropic in tincture form. Over the past decade, the plant has attracted increasing attention for its possible applications in promoting a sense of wellbeing and relieving stress in healthy individuals and for treating clinical anxiety and depression. The pharmacological actions of a standardized extract of the plant (Zembrin) have been reported to be dual PDE4 inhibition and 5-HT reuptake inhibition, a combination that has been argued to offer potential therapeutic advantages. Here we tested the acute effects of Zembrin administration in a pharmaco-fMRI study focused on anxiety-related activity in the amygdala and its connected neurocircuitry. In a double-blind, placebo-controlled, cross-over design, 16 healthy participants were scanned during performance in a perceptual-load and an emotion-matching task. Amygdala reactivity to fearful faces under low perceptual load conditions was attenuated after a single 25 mg dose of Zembrin. Follow-up connectivity analysis on the emotion-matching task showed that amygdala-hypothalamus coupling was also reduced. These results demonstrate, for the first time, the attenuating effects of S. tortuosum on the threat circuitry of the human brain and provide supporting evidence that the dual 5-HT reuptake inhibition and PDE4 inhibition of this extract might have anxiolytic potential by attenuating subcortical threat responsivity.
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Yildirim BO, Derksen JJ. Systematic review, structural analysis, and new theoretical perspectives on the role of serotonin and associated genes in the etiology of psychopathy and sociopathy. Neurosci Biobehav Rev 2013; 37:1254-96. [DOI: 10.1016/j.neubiorev.2013.04.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 04/09/2013] [Accepted: 04/17/2013] [Indexed: 12/18/2022]
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Regulating Prefrontal Cortex Activation: An Emerging Role for the 5-HT2A Serotonin Receptor in the Modulation of Emotion-Based Actions? Mol Neurobiol 2013; 48:841-53. [DOI: 10.1007/s12035-013-8472-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/06/2013] [Indexed: 10/26/2022]
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Savitz JB, Drevets WC. Neuroreceptor imaging in depression. Neurobiol Dis 2013; 52:49-65. [DOI: 10.1016/j.nbd.2012.06.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 05/21/2012] [Accepted: 06/02/2012] [Indexed: 02/08/2023] Open
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Fisher PM, Hariri AR. Identifying serotonergic mechanisms underlying the corticolimbic response to threat in humans. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120192. [PMID: 23440464 DOI: 10.1098/rstb.2012.0192] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A corticolimbic circuit including the amygdala and medial prefrontal cortex (mPFC) plays an important role in regulating sensitivity to threat, which is heightened in mood and anxiety disorders. Serotonin is a potent neuromodulator of this circuit; however, specific serotonergic mechanisms mediating these effects are not fully understood. Recent studies have evaluated molecular mechanisms mediating the effects of serotonin signalling on corticolimbic circuit function using a multi-modal neuroimaging strategy incorporating positron emission tomography and blood oxygen level-dependent functional magnetic resonance imaging. This multi-modal neuroimaging strategy can be integrated with additional techniques including imaging genetics and pharmacological challenge paradigms to more clearly understand how serotonin signalling modulates neural pathways underlying sensitivity to threat. Integrating these methodological approaches offers novel opportunities to identify mechanisms through which serotonin signalling contributes to differences in brain function and behaviour, which in turn can illuminate factors that confer risk for illness and inform the development of more effective treatment strategies.
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Affiliation(s)
- Patrick M Fisher
- Center for Integrated Molecular Brain Imaging, University of Copenhagen, Copenhagen 2100, Denmark.
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Donaldson ZR, Nautiyal KM, Ahmari SE, Hen R. Genetic approaches for understanding the role of serotonin receptors in mood and behavior. Curr Opin Neurobiol 2013; 23:399-406. [PMID: 23385115 DOI: 10.1016/j.conb.2013.01.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 01/03/2013] [Accepted: 01/13/2013] [Indexed: 01/06/2023]
Abstract
Serotonin (5-hydroxytryptamine; 5-HT) is an ancient signaling molecule that has a conserved role in modulating mood and behavior. Integral to its pleiotropic actions is the existence of multiple receptors, expressed in distinct but often overlapping patterns within the brain and the periphery. The existence of ∼14 mammalian receptor subtypes, many of which possess similar pharmacological profiles, has made assigning functional roles for these receptors challenging. This challenge has been further compounded by the revelation that a single receptor can have several different functions depending upon where and when it is expressed and activated, that is, in brain versus periphery, or at different developmental time points. This review highlights the contribution of genetic techniques to dissect the specific function of distinct serotonin receptor populations across the life course, with an emphasis on the contribution of different serotonin 1A receptor populations to mood and behavior. Similar approaches hold the promise to elucidate the functional roles of other receptors, as well as the interaction of serotonin with other neuroendocrine modulators of mood and behavior.
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Affiliation(s)
- Zoe R Donaldson
- Departments of Psychiatry and Neuroscience, Columbia University, New York, NY 10032, USA.
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Fisher PM, Hariri AR. Linking variability in brain chemistry and circuit function through multimodal human neuroimaging. GENES BRAIN AND BEHAVIOR 2012; 11:633-42. [PMID: 22443230 DOI: 10.1111/j.1601-183x.2012.00786.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Identifying neurobiological mechanisms mediating the emergence of individual differences in behavior is critical for advancing our understanding of relative risk for psychopathology. Neuroreceptor positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) can be used to assay in vivo regional brain chemistry and function, respectively. Typically, these neuroimaging modalities are implemented independently despite the capacity for integrated data sets to offer unique insight into molecular mechanisms associated with brain function. Through examples from the serotonin and dopamine system and its effects on threat- and reward-related brain function, we review evidence for how such a multimodal neuroimaging strategy can be successfully implemented. Furthermore, we discuss how multimodal PET-fMRI can be integrated with techniques such as imaging genetics, pharmacological challenge paradigms and gene-environment interaction models to more completely map biological pathways mediating individual differences in behavior and related risk for psychopathology and inform the development of novel therapeutic targets.
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Affiliation(s)
- P M Fisher
- Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
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