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Gärtner M, Weigand A, Meiering MS, Weigner D, Carstens L, Keicher C, Hertrampf R, Beckmann C, Mennes M, Wunder A, Grimm S. Region- and time- specific effects of ketamine on cerebral blood flow: a randomized controlled trial. Neuropsychopharmacology 2023; 48:1735-1741. [PMID: 37231079 PMCID: PMC10579356 DOI: 10.1038/s41386-023-01605-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 05/04/2023] [Accepted: 05/07/2023] [Indexed: 05/27/2023]
Abstract
There is intriguing evidence suggesting that ketamine might have distinct acute and delayed neurofunctional effects, as its acute administration transiently induces schizophrenia-like symptoms, while antidepressant effects slowly emerge and are most pronounced 24 h after administration. Studies attempting to characterize ketamine's mechanism of action by using blood oxygen level dependent (BOLD) imaging have yielded inconsistent results regarding implicated brain regions and direction of effects. This may be due to intrinsic properties of the BOLD contrast, while cerebral blood flow (CBF), as measured with arterial spin labeling, is a single physiological marker more directly related to neural activity. As effects of acute ketamine challenge are sensitive to modulation by pretreatment with lamotrigine, which inhibits glutamate release, a combination of these approaches should be particularly suited to offer novel insights. In total, 75 healthy participants were investigated in a double blind, placebo-controlled, randomized, parallel-group study and underwent two scanning sessions (acute/post 24 h.). Acute ketamine administration was associated with higher perfusion in interior frontal gyrus (IFG) and dorsolateral prefrontal cortex (DLPFC), but no other investigated brain region. Inhibition of glutamate release by pretreatment with lamotrigine abolished ketamine's effect on perfusion. At the delayed time point, pretreatment with lamotrigine was associated with lower perfusion in IFG. These findings underscore the idea that regionally selective patterns of CBF changes reflect proximate effects of modulated glutamate release on neuronal activity. Furthermore, region- specific sustained effects indicate both a swift restoration of disturbed homeostasis in DLPFC as well changes occurring beyond the immediate effects on glutamate signaling in IFG.
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Affiliation(s)
- Matti Gärtner
- Medical School Berlin, Berlin, Germany.
- Department of Psychiatry and Psychotherapy, Charité, Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Berlin, Germany.
| | | | | | | | | | | | | | | | | | - Andreas Wunder
- Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Simone Grimm
- Medical School Berlin, Berlin, Germany
- Department of Psychiatry and Psychotherapy, Charité, Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität Zu Berlin, Berlin, Germany
- Department of Psychiatry, Psychotherapy and Psychosomatics, University Hospital of Psychiatry, University of Zurich, Zurich, Switzerland
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Iannotti GR, Nadin I, Ivanova V, Tourdot Q, Lascano AM, Momjian S, Schaller KL, Lovblad KO, Grouiller F. Specificity of Quantitative Functional Brain Mapping with Arterial Spin-Labeling for Preoperative Assessment. AJNR Am J Neuroradiol 2023; 44:1302-1308. [PMID: 37857448 PMCID: PMC10631521 DOI: 10.3174/ajnr.a8006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 08/28/2023] [Indexed: 10/21/2023]
Abstract
BACKGROUND AND PURPOSE Arterial spin-labeling is a noninvasive MR imaging technique allowing direct and quantitative measurement of brain perfusion. Arterial spin-labeling is well-established in clinics for investigating the overall cerebral perfusion, but it is still occasionally employed during tasks. The typical contrast for functional MR imaging is blood oxygen level-dependent (BOLD) imaging, whose specificity could be biased in neurologic patients due to altered neurovascular coupling. This work aimed to validate the use of functional ASL as a noninvasive tool for presurgical functional brain mapping. This is achieved by comparing the spatial accuracy of functional ASL with transcranial magnetic stimulation as the criterion standard. MATERIALS AND METHODS Twenty-eight healthy participants executed a motor task and received a somatosensory stimulation, while BOLD imaging and arterial spin-labeling were acquired simultaneously. Transcranial magnetic stimulation was subsequently used to define hand somatotopy. RESULTS Functional ASL was found more adjacent to transcranial magnetic stimulation than BOLD imaging, with a significant shift along the inferior-to-superior direction. With respect to BOLD imaging, functional ASL was localized significantly more laterally, anteriorly, and inferiorly during motor tasks and pneumatic stimulation. CONCLUSIONS Our results confirm the specificity of functional ASL in targeting the regional neuronal excitability. Functional ASL could be considered as a valid supplementary technique to BOLD imaging for presurgical mapping when spatial accuracy is crucial for delineating eloquent cortex.
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Affiliation(s)
- Giannina R Iannotti
- From the Division of Neuroradiology, Diagnostic Department (G.R.I., K.O.L.), Geneva University Hospitals and University of Geneva, Geneva, Switzerland
- Department of Neurosurgery (G.R.I., I.N., V.I., S.M., K.L.S.), Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Isaure Nadin
- Department of Neurosurgery (G.R.I., I.N., V.I., S.M., K.L.S.), Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Vladimira Ivanova
- Department of Neurosurgery (G.R.I., I.N., V.I., S.M., K.L.S.), Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Quentin Tourdot
- Faculty of Pharmacy (Q.T.), University of Montpellier, Montpellier, France
| | - Agustina M Lascano
- Division of Neurology (A.M.L.), Department of Clinical Neuroscience, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Shahan Momjian
- Department of Neurosurgery (G.R.I., I.N., V.I., S.M., K.L.S.), Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Karl L Schaller
- Department of Neurosurgery (G.R.I., I.N., V.I., S.M., K.L.S.), Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Karl O Lovblad
- From the Division of Neuroradiology, Diagnostic Department (G.R.I., K.O.L.), Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Frederic Grouiller
- Swiss Centre for Affective Sciences (F.G.), University of Geneva, Geneva, Switzerland
- Center for Biomedical Imaging (F.G.), MRI University of Geneva Cognitive and Affective Neuroimaging Section, Geneva, Switzerland
- Laboratory of Neurology and Imaging of Cognition (F.G.), Department of Basic Neurosciences, University of Geneva, Geneva, Switzerland
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3
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Blaine S, Fogelman N, Lacadie C, Constable T, Sinha R. Blunted neural reward response to alcohol and greater alcohol motivation in binge drinkers in a randomized clinical experiment. ALCOHOL, CLINICAL & EXPERIMENTAL RESEARCH 2023; 47:1067-1078. [PMID: 37070596 PMCID: PMC10289130 DOI: 10.1111/acer.15082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 04/04/2023] [Accepted: 04/07/2023] [Indexed: 04/19/2023]
Abstract
BACKGROUND Alcohol stimulates cerebral blood flow (CBF) in brain reward regions. However, neural processes that support sustained alcohol motivation after the first drink are not well understood. METHODS Using a novel placebo-controlled, randomized, crossover experiment, 27 individuals who binge drink (BD; 15 M, 12 F) and 25 social drinkers (SD; 15 M, 10 F) underwent a behavioral test of self-motivated alcohol consumption using an Alcohol Taste Test (ATT) involving alcoholic and nonalcoholic beer on separate days. The test was followed immediately by perfusion functional magnetic resonance imaging (fMRI). On both days, participants then engaged in a post-scan ATT with placebo beer to assess sustained alcohol self-motivation without active alcohol effects. Linear mixed effects models were used to examine the effects of drinking group on the placebo-controlled effect of initial alcohol motivation on brain perfusion (whole brain corrected p < 0.001, cluster corrected p < 0.025) and on the relationship between placebo-controlled brain perfusion and sustained alcohol motivation. RESULTS Initial alcohol self-motivation in the alcohol relative to placebo session led to markedly decreased activation in the medial orbitofrontal cortex (OFC) and the ventral striatum in BD relative to SD, indicative of neural reward tolerance. The BD group also showed an enhanced neural response in behavioral intention regions of the supplementary motor area (SMA) and inferior frontal gyrus (IFG) regions. Moreover, there was greater sustained alcohol motivation in BD than SD in the post-scan ATT in the alcohol relative to placebo session. Correspondingly, only in BD and only in the alcohol session, lower alcohol-induced OFC response correlated with concurrent sensitized SMA response, and each predicted the subsequent sustained higher alcohol motivation in the post-scan ATT. CONCLUSIONS Alcohol-related OFC tolerance may play an important role in sustained alcohol motivation. Furthermore, both specific alcohol-related neural reward tolerance and premotor sensitization responses may contribute to escalating alcohol motivation to drive excessive alcohol intake, even in individuals without alcohol use disorder.
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Affiliation(s)
- Sara Blaine
- Department of Psychological Sciences, Auburn University; Auburn, AL
- Department of Psychiatry, Yale School of Medicine; New Haven, CT
| | - Nia Fogelman
- Department of Psychiatry, Yale School of Medicine; New Haven, CT
| | - Cheryl Lacadie
- Department of Radiology and Biomedical Imaging, Yale School of Medicine; New Haven, CT
| | - Todd Constable
- Department of Radiology and Biomedical Imaging, Yale School of Medicine; New Haven, CT
| | - Rajita Sinha
- Department of Psychiatry, Yale School of Medicine; New Haven, CT
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4
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Doyen M, Hossu G, Heyer S, Zaragori T, Imbert L, Verger A. Identification of resting-state networks using dynamic brain perfusion SPECT imaging: A fSPECT case report. Front Hum Neurosci 2023; 17:1125765. [PMID: 37151905 PMCID: PMC10157397 DOI: 10.3389/fnhum.2023.1125765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 03/21/2023] [Indexed: 05/09/2023] Open
Abstract
Connectivity studies with nuclear medicine systems are scarce in literature. They mainly employ PET imaging and group level analyses due to the low temporal resolution of PET and especially SPECT imaging. Our current study analyses connectivity at an individual level using dynamic SPECT imaging, which has been enabled by the improved temporal resolution performances provided by the 360°CZT cameras. We present the case of an 80-year-old man referred for brain perfusion SPECT imaging for cognitive disorders for whom a dynamic SPECT acquisition was performed utilizing a 360°CZT camera (temporal sampling of 15 frames × 3 s, 10 frames × 15 s, 14 frames × 30 s), followed by a conventional static acquisition of 15 m. Functional SPECT connectivity (fSPECT) was assessed through a seed correlation analysis and 5 well-known resting-state networks were identified: the executive, the default mode, the sensory motor, the salience, and the visual networks. This case report supports the feasibility of fSPECT imaging to identify well known resting-state networks, thanks to the novel properties of a 360°CZT camera, and opens the way to the development of more dedicated functional connectivity studies using brain perfusion SPECT imaging.
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Affiliation(s)
- Matthieu Doyen
- Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, Université de Lorraine, Nancy, France
- IADI, INSERM U1254, Université de Lorraine, Nancy, France
- *Correspondence: Matthieu Doyen,
| | - Gabriela Hossu
- IADI, INSERM U1254, Université de Lorraine, Nancy, France
- CHRU-Nancy, INSERM, CIC, Innovation Technologique, Université de Lorraine, Nancy, France
| | - Sébastien Heyer
- Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, Université de Lorraine, Nancy, France
| | | | - Laetitia Imbert
- Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, Université de Lorraine, Nancy, France
- IADI, INSERM U1254, Université de Lorraine, Nancy, France
| | - Antoine Verger
- Department of Nuclear Medicine and Nancyclotep Imaging Platform, CHRU Nancy, Université de Lorraine, Nancy, France
- IADI, INSERM U1254, Université de Lorraine, Nancy, France
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Gärtner M, de Rover M, Václavů L, Scheidegger M, van Osch MJP, Grimm S. Increase in thalamic cerebral blood flow is associated with antidepressant effects of ketamine in major depressive disorder. World J Biol Psychiatry 2022; 23:643-652. [PMID: 34985394 DOI: 10.1080/15622975.2021.2020900] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Ketamine is a promising treatment option for patients with Major Depressive Disorder (MDD) and has become an important research tool to investigate antidepressant mechanisms of action. However, imaging studies attempting to characterise ketamine's mechanism of action using blood oxygen level-dependent signal (BOLD) imaging have yielded inconsistent results- at least partly due to intrinsic properties of the BOLD contrast, which measures a complex signal related to neural activity. To circumvent the limitations associated with the BOLD signal, we used arterial spin labelling (ASL) as an unambiguous marker of neuronal activity-related changes in cerebral blood flow (CBF). We measured CBF in 21 MDD patients at baseline and 24 h after receiving a single intravenous infusion of subanesthetic ketamine and examined relationships with clinical outcomes. Our findings demonstrate that increase in thalamus perfusion 24 h after ketamine administration is associated with greater improvement of depressive symptoms. Furthermore, lower thalamus perfusion at baseline is associated both with larger increases in perfusion 24 h after ketamine administration and with stronger reduction of depressive symptoms. These findings indicate that ASL is not only a useful tool to broaden our understanding of ketamine's mechanism of action but might also have the potential to inform treatment decisions based on CBF-defined regional disruptions.
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Affiliation(s)
- Matti Gärtner
- MSB-Medical School Berlin, Berlin, Germany.,Department of Psychiatry and Psychotherapy, Campus Benjamin Franklin, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Mischa de Rover
- Laboratory for Neurophysiology, Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, Netherlands.,Department of Clinical Psychology, Institute of Psychology, Leiden University, Leiden, Netherlands
| | - Lena Václavů
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Milan Scheidegger
- Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Matthias J P van Osch
- Department of Radiology, C.J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands
| | - Simone Grimm
- MSB-Medical School Berlin, Berlin, Germany.,Department of Psychiatry and Psychotherapy, Campus Benjamin Franklin, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
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6
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Investigating resting brain perfusion abnormalities and disease target-engagement by intranasal oxytocin in women with bulimia nervosa and binge-eating disorder and healthy controls. Transl Psychiatry 2020; 10:180. [PMID: 32513936 PMCID: PMC7280271 DOI: 10.1038/s41398-020-00871-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 05/19/2020] [Accepted: 05/26/2020] [Indexed: 12/25/2022] Open
Abstract
Advances in the treatment of bulimia nervosa and binge-eating disorder (BN/BED) have been marred by our limited understanding of the underpinning neurobiology. Here we measured regional cerebral blood flow (rCBF) to map resting perfusion abnormalities in women with BN/BED compared with healthy controls and investigate whether intranasal oxytocin (OT), proposed as a potential treatment, can restore perfusion in disorder-related brain circuits. Twenty-four women with BN/BED and 23 healthy women participated in a randomized, double-blind, crossover, placebo-controlled study. We used arterial spin labelling MRI to measure rCBF and the effects of an acute dose of intranasal OT (40 IU) or placebo over 18-26 min post dosing, as we have previously shown robust OT-induced changes in resting rCBF in men in a similar time-window (15-36 min post dosing). We tested for effects of treatment, diagnosis and their interaction on extracted rCBF values in anatomical regions-of-interest previously implicated in BN/BED by other neuroimaging modalities, and conducted exploratory whole-brain analyses to investigate previously unidentified brain regions. We demonstrated that women with BN/BED presented increased resting rCBF in the medial prefrontal and orbitofrontal cortices, anterior cingulate gyrus, posterior insula and middle/inferior temporal gyri bilaterally. Hyperperfusion in these areas specifically correlated with eating symptoms severity in patients. Our data did not support a normalizing effect of intranasal OT on perfusion abnormalities in these patients, at least for the specific dose (40 IU) and post-dosing interval (18-26 min) examined. Our findings enhance our understanding of resting brain abnormalities in BN/BED and identify resting rCBF as a non-invasive potential biomarker for disease-related changes and treatment monitoring. They also highlight the need for a comprehensive investigation of intranasal OT pharmacodynamics in women before we can fully ascertain its therapeutic value in disorders affecting predominantly this gender, such as BN/BED.
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7
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Black KJ, Kim S, Schlaggar BL, Greene DJ. The New Tics study: A Novel Approach to Pathophysiology and Cause of Tic Disorders. JOURNAL OF PSYCHIATRY AND BRAIN SCIENCE 2020; 5:e200012. [PMID: 32587895 PMCID: PMC7316401 DOI: 10.20900/jpbs.20200012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We report on the ongoing project "The New Tics Study: A Novel Approach to Pathophysiology and Cause of Tic Disorders," describing the work completed to date, ongoing studies and long-term goals. The overall goals of this research are to study the pathophysiology of Provisional Tic Disorder, and to study tic remission (or improvement) in a prospective fashion. Preliminary data collection for the project began almost 10 years ago. The current study is nearing completion of its third year, and has already reported several novel and important results. First, surprisingly, at least 90% of children who had experienced tics for only a mean of 3 months still had tics at the 12-month anniversary of their first tic, though in some cases tics were seen only with remote video observation of the child sitting alone. Thus almost all of them now had a DSM-5 diagnosis of Tourette's Disorder or Persistent (Chronic) Tic Disorder. Baseline clinical features that predicted 12-month outcome included tic severity, subsyndromal autism spectrum symptoms, an anxiety disorder, and a history of 3 or more phonic tics. Second, we found that poorer tic suppression ability when immediately rewarded for suppression predicted greater tic severity at follow-up. Third, striatal volumes did not predict outcome as hypothesized, but a larger hippocampus at baseline predicted worse severity at follow-up. Enrollment and data collection continue, including functional connectivity MRI (fcMRI) imaging, and additional analyses are planned once the full sample is enrolled.
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Affiliation(s)
- Kevin J. Black
- Departments of Psychiatry, Neurology, Radiology and Neuroscience, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA
| | - Soyoung Kim
- Departments of Psychiatry and Radiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA
| | - Bradley L. Schlaggar
- Kennedy Krieger Institute, Baltimore, MD 21205; and Departments of Neurology and Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Deanna J. Greene
- Departments of Psychiatry and Radiology, Washington University in St. Louis School of Medicine, St. Louis, MO 63110, USA
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8
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Black KJ, Acevedo HK, Koller JM. Dopamine Buffering Capacity Imaging: A Pharmacodynamic fMRI Method for Staging Parkinson Disease. Front Neurol 2020; 11:370. [PMID: 32477245 PMCID: PMC7232584 DOI: 10.3389/fneur.2020.00370] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 04/14/2020] [Indexed: 11/13/2022] Open
Abstract
We propose a novel pharmacological fMRI (phMRI) method for objectively quantifying disease severity in Parkinson disease (PD). It is based on the clinical observation that the benefit from a dose of levodopa wears off more quickly as PD progresses. Biologically this has been thought to represent decreased buffering capacity for dopamine as nigrostriatal cells die. Buffering capacity has been modeled based on clinical effects, but clinical measurements are influenced by confounding factors. The new method proposes to measure the effect objectively based on the timing of the known response of several brain regions to exogenous levodopa. Such responses are robust and can be quantified using perfusion MRI. Here we present simulation studies based on published clinical dose-response data and an intravenous levodopa infusion. Standard pharmacokinetic-pharmacodynamic methods were used to model the response. Then the effect site rate constant k e was estimated from simulated response data plus Gaussian noise. Predicted time - effect curves sampled at times consistent with phMRI differ substantially based on clinical severity. Estimated k e from noisy input data was recovered with good accuracy. These simulation results support the feasibility of levodopa phMRI hysteresis mapping to measure the severity of dopamine denervation objectively and simultaneously in all brain regions with a robust imaging response to exogenous levodopa.
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Affiliation(s)
- Kevin J. Black
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, United States
- Departments of Neurology, Radiology and Neuroscience, Washington University in St. Louis, St. Louis, MO, United States
| | - Haley K. Acevedo
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, United States
| | - Jonathan M. Koller
- Department of Psychiatry, Washington University in St. Louis, St. Louis, MO, United States
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Douglas KM, Groves S, Porter RJ, Jordan J, Wilson L, Melzer TR, Wise RG, Bisson JI, Bell CJ. Traumatic imagery following glucocorticoid administration in earthquake-related post-traumatic stress disorder: A preliminary functional magnetic resonance imaging study. Aust N Z J Psychiatry 2019; 53:1167-1178. [PMID: 31146540 DOI: 10.1177/0004867419851860] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Post-traumatic stress disorder involves excessive retrieval of traumatic memories. Glucocorticoids impair declarative memory retrieval. This preliminary study examined the effect of acute hydrocortisone administration on brain activation in individuals with earthquake-related post-traumatic stress disorder compared with earthquake-exposed healthy individuals, during retrieval of traumatic memories. METHOD Participants exposed to earthquakes with (n = 11) and without post-traumatic stress disorder (n = 11) underwent two functional magnetic resonance imaging scans, 1-week apart, in a double-blind, placebo-controlled, counter-balanced design. On one occasion, they received oral hydrocortisone (20 mg), and on the other, placebo, 1 hour before scanning. Symptom provocation involved script-driven imagery (traumatic and neutral scripts) and measures of self-reported anxiety. RESULTS Arterial spin labelling showed that both post-traumatic stress disorder and trauma-exposed controls had significantly reduced cerebral blood flow in response to retrieval of traumatic versus neutral memories in the right hippocampus, parahippocampal gyrus, calcarine sulcus, middle and superior temporal gyrus, posterior cingulate, Heschl's gyrus, inferior parietal lobule, angular gyrus, middle occipital gyrus, supramarginal gyrus, lingual gyrus and cuneus, and the left prefrontal cortex. Hydrocortisone resulted in non-significant trends of increasing subjective distress and reduced regional cerebral blood flow in the left inferior frontal gyrus, left anterior cingulate gyrus, middle temporal gyrus, cerebellum, postcentral gyrus and right frontal pole, during the trauma script. CONCLUSION Findings do not fit with some aspects of the accepted neurocircuitry model of post-traumatic stress disorder, i.e., failure of the medial prefrontal cortex to quieten hyperresponsive amygdala activity, and the potential therapeutic benefits of hydrocortisone. They do, however, provide further evidence that exposure to earthquake trauma, regardless of whether post-traumatic stress disorder eventuates, impacts brain activity and highlights the importance of inclusion of trauma-exposed comparisons in studies of post-traumatic stress disorder.
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Affiliation(s)
- Katie M Douglas
- Department of Psychological Medicine, University of Otago, Christchurch, Christchurch, New Zealand
| | - Samantha Groves
- Department of Psychological Medicine, University of Otago, Christchurch, Christchurch, New Zealand.,New Zealand Brain Research Institute, Christchurch, New Zealand.,Department of Medicine, University of Otago, Christchurch, Christchurch, New Zealand
| | - Richard J Porter
- Department of Psychological Medicine, University of Otago, Christchurch, Christchurch, New Zealand
| | - Jenny Jordan
- Department of Psychological Medicine, University of Otago, Christchurch, Christchurch, New Zealand
| | - Lynere Wilson
- Department of Psychological Medicine, University of Otago, Christchurch, Christchurch, New Zealand
| | - Tracy R Melzer
- New Zealand Brain Research Institute, Christchurch, New Zealand.,Department of Medicine, University of Otago, Christchurch, Christchurch, New Zealand
| | - Richard G Wise
- Brain Research Imaging Centre, School of Psychology, Cardiff University, Cardiff
| | | | - Caroline J Bell
- Department of Psychological Medicine, University of Otago, Christchurch, Christchurch, New Zealand
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10
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Nwokolo M, Amiel SA, O'Daly O, Byrne ML, Wilson BM, Pernet A, Cordon SM, Macdonald IA, Zelaya FO, Choudhary P. Impaired Awareness of Hypoglycemia Disrupts Blood Flow to Brain Regions Involved in Arousal and Decision Making in Type 1 Diabetes. Diabetes Care 2019; 42:2127-2135. [PMID: 31455689 DOI: 10.2337/dc19-0337] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Accepted: 08/07/2019] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Impaired awareness of hypoglycemia (IAH) affects one-quarter of adults with type 1 diabetes and significantly increases the risk of severe hypoglycemia. Differences in regional brain responses to hypoglycemia may contribute to the susceptibility of this group to problematic hypoglycemia. This study investigated brain responses to hypoglycemia in hypoglycemia aware (HA) and IAH adults with type 1 diabetes, using three-dimensional pseudo-continuous arterial spin labeling (3D pCASL) functional MRI to measure changes in regional cerebral blood flow (CBF). RESEARCH DESIGN AND METHODS Fifteen HA and 19 IAH individuals underwent 3D pCASL functional MRI during a two-step hyperinsulinemic glucose clamp. Symptom, hormone, global, and regional CBF responses to hypoglycemia (47 mg/dL [2.6 mmol/L]) were measured. RESULTS In response to hypoglycemia, total symptom score did not change in those with IAH (P = 0.25) but rose in HA participants (P < 0.001). Epinephrine, cortisol, and growth hormone responses to hypoglycemia were lower in the IAH group (P < 0.05). Hypoglycemia induced a rise in global CBF (HA P = 0.01, IAH P = 0.04) but was not different between groups (P = 0.99). IAH participants showed reduced regional CBF responses within the thalamus (P = 0.002), right lateral orbitofrontal cortex (OFC) (P = 0.002), and right dorsolateral prefrontal cortex (P = 0.036) and a lesser decrease of CBF in the left hippocampus (P = 0.023) compared with the HA group. Thalamic and right lateral OFC differences survived Bonferroni correction. CONCLUSIONS Responses to hypoglycemia of brain regions involved in arousal, decision making, and reward are altered in IAH. Changes in these pathways may disrupt IAH individuals' ability to recognize hypoglycemia, impairing their capacity to manage hypoglycemia effectively and benefit fully from conventional therapeutic pathways to restore awareness.
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Affiliation(s)
- Munachiso Nwokolo
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K. .,King's College Hospital NHS Foundation Trust, London, U.K
| | - Stephanie A Amiel
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K.,King's College Hospital NHS Foundation Trust, London, U.K
| | - Owen O'Daly
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, U.K
| | - Megan L Byrne
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K
| | - Bula M Wilson
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K
| | - Andrew Pernet
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K
| | - Sally M Cordon
- School of Life Sciences, MRC Arthritis Research UK Centre of Excellence in Musculoskeletal Ageing, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, U.K
| | - Ian A Macdonald
- School of Life Sciences, MRC Arthritis Research UK Centre of Excellence in Musculoskeletal Ageing, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, U.K
| | - Fernando O Zelaya
- Department of Neuroimaging, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, U.K
| | - Pratik Choudhary
- Department of Diabetes, School of Life Course Sciences, King's College London, London, U.K.,King's College Hospital NHS Foundation Trust, London, U.K
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Bryant JE, Frölich M, Tran S, Reid MA, Lahti AC, Kraguljac NV. Ketamine induced changes in regional cerebral blood flow, interregional connectivity patterns, and glutamate metabolism. J Psychiatr Res 2019; 117:108-115. [PMID: 31376621 PMCID: PMC7291620 DOI: 10.1016/j.jpsychires.2019.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/19/2019] [Accepted: 07/26/2019] [Indexed: 12/31/2022]
Abstract
Several imaging studies have attempted to characterize the contribution of glutamatergic dysfunction to functional dysconnectivity of large-scale brain networks using ketamine models. However, findings from BOLD imaging studies are conflicting, in part because the signal stems from a complex interaction between blood flow, blood volume, and oxygen consumption. We used arterial spin labelling imaging to measure regional cerebral blood flow (rCBF) in a group of healthy volunteers during a saline and during a ketamine infusion. We examined changes in rCBF and interregional connectivity patterns, as well as their associations with clinical symptom severity and Glx (glutamate + glutamine) assessed with magnetic resonance spectroscopy. We report a regionally selective pattern of rCBF changes following ketamine administration and complex changes in interregional connectivity patterns. We also found that the increase in rCBF in the bilateral putamen and left hippocampus was positively correlated with ketamine induced clinical symptom severity while anterior cingulate rCBF during the ketamine challenge was negatively correlated with change in hippocampal Glx. Our study adds to the efforts to empirically confirm putative links between an NMDA receptor blockage and dysconnectivity of large-scale brain networks, specifically the salience, executive control and default mode networks, suggesting that a glutamatergic imbalance may contribute to dysconnectivity. Development of glutamatergic compounds that alleviate disease burden, possibly through normalizing glutamate excess related increased rCBF, is direly needed.
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Affiliation(s)
- James Edward Bryant
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, United States
| | - Michael Frölich
- Department of Anesthesiology, University of Alabama at Birmingham, United States
| | - Steve Tran
- Department of Anesthesiology, University of Alabama at Birmingham, United States
| | - Meredith Amanda Reid
- MRI Research Center, Department of Electrical and Computer Engineering, Auburn University, United States
| | - Adrienne Carol Lahti
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, United States
| | - Nina Vanessa Kraguljac
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, United States.
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12
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Harvey JL, Demetriou L, McGonigle J, Wall MB. A short, robust brain activation control task optimised for pharmacological fMRI studies. PeerJ 2018; 6:e5540. [PMID: 30221091 PMCID: PMC6138041 DOI: 10.7717/peerj.5540] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 08/07/2018] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Functional magnetic resonance imaging (fMRI) is a popular method for examining pharmacological effects on the brain; however, the BOLD response is dependent on intact neurovascular coupling, and potentially modulated by a number of physiological factors. Pharmacological fMRI is therefore vulnerable to confounding effects of pharmacological probes on general physiology or neurovascular coupling. Controlling for such non-specific effects in pharmacological fMRI studies is therefore an important consideration, and there is an additional need for well-validated fMRI task paradigms that could be used to control for such effects, or for general testing purposes. METHODS We have developed two variants of a standardized control task that are short (5 minutes duration) simple (for both the subject and experimenter), widely applicable, and yield a number of readouts in a spatially diverse set of brain networks. The tasks consist of four functionally discrete three-second trial types (plus additional null trials) and contain visual, auditory, motor and cognitive (eye-movements, and working memory tasks in the two task variants) stimuli. Performance of the tasks was assessed in a group of 15 subjects scanned on two separate occasions, with test-retest reliability explicitly assessed using intra-class correlation coefficients. RESULTS Both tasks produced robust patterns of brain activation in the expected brain regions, and region of interest-derived reliability coefficients for the tasks were generally high, with four out of eight task conditions rated as 'excellent' or 'good', and only one out of eight rated as 'poor'. Median values in the voxel-wise reliability measures were also >0.7 for all task conditions, and therefore classed as 'excellent' or 'good'. The spatial concordance between the most highly activated voxels and those with the highest reliability coefficients was greater for the sensory (auditory, visual) conditions than the other (motor, cognitive) conditions. DISCUSSION Either of the two task variants would be suitable for use as a control task in future pharmacological fMRI studies or for any other investigation where a short, reliable, basic task paradigm is required. Stimulus code is available online for re-use by the scientific community.
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Affiliation(s)
- Jessica-Lily Harvey
- School of Psychology and Neuroscience, University of St. Andrews, St Andrews, United Kingdom
- Division of Brain Sciences, Imperial College London, London, United Kingdom
| | - Lysia Demetriou
- Invicro Ltd., London, United Kingdom
- Department of Medicine, Imperial College London, London, United Kingdom
| | - John McGonigle
- Division of Brain Sciences, Imperial College London, London, United Kingdom
- Perspectum Diagnostics, Oxford, United Kingdom
| | - Matthew B. Wall
- Division of Brain Sciences, Imperial College London, London, United Kingdom
- Invicro Ltd., London, United Kingdom
- Clinical Psychopharmacology Unit, University College London, University of London, London, United Kingdom
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13
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Tuite P. Brain Magnetic Resonance Imaging (MRI) as a Potential Biomarker for Parkinson's Disease (PD). Brain Sci 2017; 7:E68. [PMID: 28621758 PMCID: PMC5483641 DOI: 10.3390/brainsci7060068] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 06/09/2017] [Accepted: 06/13/2017] [Indexed: 12/14/2022] Open
Abstract
Magnetic resonance imaging (MRI) has the potential to serve as a biomarker for Parkinson's disease (PD). However, the type or types of biomarker it could provide remain to be determined. At this time there is not sufficient sensitivity or specificity for MRI to serve as an early diagnostic biomarker, i.e., it is unproven in its ability to determine if a single individual is normal, has mild PD, or has some other forms of degenerative parkinsonism. However there is accumulating evidence that MRI may be useful in staging and monitoring disease progression (staging biomarker), and also possibly as a means to monitor pathophysiological aspects of disease and associated response to treatments, i.e., theranostic marker. As there are increasing numbers of manuscripts that are dedicated to diffusion- and neuromelanin-based imaging methods, this review will focus on these topics cursorily and will delve into pharmacodynamic imaging as a means to get at theranostic aspects of PD.
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Affiliation(s)
- Paul Tuite
- Neurology Department, University of Minnesota, MMC 295, 420 Delaware St SE, Minneapolis, MN 55455, USA.
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14
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Syrimi ZJ, Vojtisek L, Eliasova I, Viskova J, Svatkova A, Vanicek J, Rektorova I. Arterial spin labelling detects posterior cortical hypoperfusion in non-demented patients with Parkinson's disease. J Neural Transm (Vienna) 2017; 124:551-557. [PMID: 28271290 DOI: 10.1007/s00702-017-1703-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 02/27/2017] [Indexed: 01/04/2023]
Abstract
While previous studies suggested that perfusion abnormalities in Parkinson's disease (PD) are driven by dementia, our study aimed to identify perfusion underpinning of cognitive alteration in non-demented PD patients. Cerebral blood flow was measured using arterial spin labelling (ASL) in 28 PD patients (age 65 years ± 9.9 SD) and 16 age-matched healthy controls (HC) (age 65 years ± 7.8 SD), who also underwent neurological and cognitive testing. The 3D pseudocontinuous ASL and T2-weighted scans from 22 PD patients and 16 HC were analysed in a voxel-wise manner using SPM8 software. Associations between the ASL values in volumes of interest (VOIs) and behavioural and cognitive measures were assessed by Spearman correlation analysis. Posterior cortical hypoperfusion was found in PD patients compared to HC in the left supramarginal gyrus/superior temporal gyrus (VOI1) and left posterior cingulate/precuneus (VOI2). Positive correlation was revealed between perfusion in the VOI2 and Addenbrooke's Cognitive Examination Revised (ACE-R) scores after filtering out the effect of age, levodopa equivalent dose (LED), and total intracranial volume (TIV) (R = 0.51, p = 0.04). Conversely, negative correlation between VOI1 and ACE-R was detected (R = -0.62, p = 0.01) after regressing out the effects of motor impairment, age, LED, and TIV. In non-demented subjects with PD, blood flow abnormalities in precuneus/posterior cingulate were linked to the level of motor impairment and global cognitive performance. Oppositely, perfusion abnormalities in supramarginal gyrus might serve as a compensatory mechanism for brain degeneration and decreased cognitive performance.
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Affiliation(s)
| | - Lubomir Vojtisek
- Multimodal and Functional Neuroimaging Research Group, CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Ilona Eliasova
- Applied Neuroscience Research Group, CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic.,First Department of Neurology, Medical Faculty, Masaryk University and St. Anne's University Hospital, Brno, Czech Republic
| | - Jana Viskova
- Applied Neuroscience Research Group, CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic.,Department of Medical Imaging, Medical Faculty, Masaryk University and St. Anne's University Hospital, Brno, Czech Republic
| | - Alena Svatkova
- Multimodal and Functional Neuroimaging Research Group, CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic.,Department of Paediatrics, University of Minnesota, Minneapolis, MN, USA
| | - Jiri Vanicek
- Department of Medical Imaging, Medical Faculty, Masaryk University and St. Anne's University Hospital, Brno, Czech Republic
| | - Irena Rektorova
- Applied Neuroscience Research Group, CEITEC-Central European Institute of Technology, Masaryk University, Brno, Czech Republic. .,First Department of Neurology, Medical Faculty, Masaryk University and St. Anne's University Hospital, Brno, Czech Republic.
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15
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Tuite P. Magnetic resonance imaging as a potential biomarker for Parkinson's disease. Transl Res 2016; 175:4-16. [PMID: 26763585 DOI: 10.1016/j.trsl.2015.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 12/09/2015] [Accepted: 12/10/2015] [Indexed: 01/01/2023]
Abstract
Although a magnetic resonance imaging (MRI) biomarker for Parkinson's disease (PD) remains an unfulfilled objective, there have been numerous developments in MRI methodology and some of these have shown promise for PD. With funding from the National Institutes of Health and the Michael J Fox Foundation there will be further validation of structural, diffusion-based, and iron-focused MRI methods as possible biomarkers for PD. In this review, these methods and other strategies such as neurochemical and metabolic MRI have been covered. One of the challenges in establishing a biomarker is in the selection of individuals as PD is a heterogeneous disease with varying clinical features, different etiologies, and a range of pathologic changes. Additionally, longitudinal studies are needed of individuals with clinically diagnosed PD and cohorts of individuals who are at great risk for developing PD to validate methods. Ultimately an MRI biomarker will be useful in the diagnosis of PD, predicting the course of PD, providing a means to track its course, and provide an approach to select and monitor treatments.
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Affiliation(s)
- Paul Tuite
- Department of Neurology, University of Minnesota, Minneapolis, Minnesota.
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16
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Chen Y, Pressman P, Simuni T, Parrish TB, Gitelman DR. Effects of acute levodopa challenge on resting cerebral blood flow in Parkinson's Disease patients assessed using pseudo-continuous arterial spin labeling. PeerJ 2015; 3:e1381. [PMID: 26734502 PMCID: PMC4699782 DOI: 10.7717/peerj.1381] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 10/14/2015] [Indexed: 01/20/2023] Open
Abstract
Introduction. Levodopa is the gold-standard for treatment of Parkinson’s disease (PD) related motor symptoms. In this study, we used pseudo-continuous arterial spin labeling (pCASL) to quantify changes in cerebral blood flow (CBF) after acute oral administration of levodopa in PD patients. Materials and Methods. Thirteen patients (3 females, age 66.2 ± 8.7 years) with moderately advanced PD (Hoehn and Yahr stage >2 (median 2.5), disease duration >3 years) were scanned on a 3T Siemens MR scanner before and after oral levodopa administration. Statistical parametric mapping was used to detect drug-induced changes in CBF and its correlation to clinical severity scales. Images were normalized and flipped in order to examine effects on the more affected (left) and less affected (right) cerebral hemispheres across the cohort. Results. Levodopa did not change global CBF but increased regional CBF in dorsal midbrain, precuneus/cuneus, more affected inferior frontal pars opercularis and triangularis, bilateral pre- and postcentral gyri, more affected inferior parietal areas, as well as less affected putamen/globus pallidus by 27–74% (p < 0.05, FWE corrected for multiple comparisons). CBF change was negatively correlated with improvement in bradykinesia UPDRS-III subscore in the more affected precentral gyrus, and total predrug UPDRS-III score in the mid-cingulate region. Drug-induced CBF change in a widespread network of regions including parietal and postcentral areas was also negatively correlated with the predrug rigidity UPDRS-III subscore. Conclusion. These findings are in line with prior reports of abnormal activity in the nigrostriatal pathway of PD patients and demonstrate the feasibility of pCASL as a neuroimaging tool for investigating in vivo physiological effects of acute drug administration in PD.
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Affiliation(s)
- Yufen Chen
- Department of Radiology, Feinberg School of Medicine, Northwestern University , Chicago, IL , USA
| | - Peter Pressman
- Department of Neurology, Memory and Aging Center, University of California , San Francisco, CA , USA
| | - Tanya Simuni
- Department of Neurology, Feinberg School of Medicine, Northwestern University , Chicago, IL , USA
| | - Todd B Parrish
- Department of Radiology, Feinberg School of Medicine, Northwestern University , Chicago, IL , USA
| | - Darren R Gitelman
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Department of Medicine, Advocate Lutheran General Hospital, Park Ridge, IL, USA; Department of Medicine, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
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17
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Stewart SB, Koller JM, Campbell MC, Perlmutter JS, Black KJ. Additive global cerebral blood flow normalization in arterial spin labeling perfusion imaging. PeerJ 2015; 3:e834. [PMID: 25802806 PMCID: PMC4369335 DOI: 10.7717/peerj.834] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 02/20/2015] [Indexed: 11/20/2022] Open
Abstract
To determine how different methods of normalizing for global cerebral blood flow (gCBF) affect image quality and sensitivity to cortical activation, pulsed arterial spin labeling (pASL) scans obtained during a visual task were normalized by either additive or multiplicative normalization of modal gCBF. Normalization by either method increased the statistical significance of cortical activation by a visual stimulus. However, image quality was superior with additive normalization, whether judged by intensity histograms or by reduced variability within gray and white matter.
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Affiliation(s)
- Stephanie B Stewart
- Department of Neurology, Washington University School of Medicine , St Louis, MO , USA ; Department of Psychiatry, Washington University School of Medicine , St Louis, MO , USA
| | - Jonathan M Koller
- Department of Psychiatry, Washington University School of Medicine , St Louis, MO , USA
| | - Meghan C Campbell
- Department of Neurology, Washington University School of Medicine , St Louis, MO , USA ; Department of Radiology, Washington University School of Medicine , St Louis, MO , USA
| | - Joel S Perlmutter
- Department of Neurology, Washington University School of Medicine , St Louis, MO , USA ; Department of Radiology, Washington University School of Medicine , St Louis, MO , USA ; Departments of Anatomy and Neurobiology, Washington University School of Medicine , St Louis, MO , USA ; Division of Biology and Biomedical Sciences, Washington University School of Medicine , St Louis, MO , USA ; Programs in Physical Therapy and Occupational Therapy, Washington University School of Medicine , St Louis, MO , USA
| | - Kevin J Black
- Department of Neurology, Washington University School of Medicine , St Louis, MO , USA ; Department of Psychiatry, Washington University School of Medicine , St Louis, MO , USA ; Department of Radiology, Washington University School of Medicine , St Louis, MO , USA ; Departments of Anatomy and Neurobiology, Washington University School of Medicine , St Louis, MO , USA ; Division of Biology and Biomedical Sciences, Washington University School of Medicine , St Louis, MO , USA
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