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Li CX, Tong F, Kempf D, Howell L, Zhang X. Longitudinal evaluation of the functional connectivity changes in the secondary somatosensory cortex (S2) of the monkey brain during acute stroke. CURRENT RESEARCH IN NEUROBIOLOGY 2023; 5:100097. [PMID: 37404949 PMCID: PMC10315998 DOI: 10.1016/j.crneur.2023.100097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 05/29/2023] [Accepted: 06/09/2023] [Indexed: 07/06/2023] Open
Abstract
Background Somatosensory deficits are frequently seen in acute stroke patients and may recover over time and affect functional outcome. However, the underlying mechanism of function recovery remains poorly understood. In the present study, progressive function alteration of the secondary somatosensory cortex (S2) and its relationship with regional perfusion and neurological outcome were examined using a monkey model of stroke. Methods and materials Rhesus monkeys (n = 4) were induced with permanent middle cerebral artery occlusion (pMCAo). Resting-state functional MRI, dynamic susceptibility contrast perfusion MRI, diffusion-weighted, T1 and T2 weighted images were collected before surgery and at 4-6, 48, and 96 h post stroke on a 3T scanner. Progressive changes of relative functional connectivity (FC), cerebral blood flow (CBF), and CBF/Tmax (Time to Maximum) of affected S2 regions were evaluated. Neurological deficits were assessed using the Spetzler approach. Results Ischemic lesion was evidently seen in the MCA territory including S2 in each monkey. Relative FC of injured S2 regions decreased substantially following stroke. Spetzler scores dropped substantially at 24 h post stroke but slightly recovered from Day 2 to Day 4. Relative FC progressively increased from 6 to 48 and 96 h post stroke and correlated significantly with relative CBFand CBF/Tmax changes. Conclusion The present study revealed the progressive alteration of function connectivity in S2 during acute stroke. The preliminary results suggested the function recovery might start couple days post occlusion and collateral circulation might play a key role in the recovery of somatosensory function after stroke insult. The relative function connectivity in S2 may provide additional information for prediction of functional outcome in stroke patients.
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Affiliation(s)
- Chun-Xia Li
- Emory National Primate Research Center, Emory University, Atlanta, 30329, Georgia
| | - Frank Tong
- Department of Radiology, Emory University School of Medicine, Atlanta, 30322, Georgia
| | - Doty Kempf
- Emory National Primate Research Center, Emory University, Atlanta, 30329, Georgia
| | - Leonard Howell
- Emory National Primate Research Center, Emory University, Atlanta, 30329, Georgia
| | - Xiaodong Zhang
- Emory National Primate Research Center, Emory University, Atlanta, 30329, Georgia
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Zhang X. Effects of Anesthesia on Cerebral Blood Flow and Functional Connectivity of Nonhuman Primates. Vet Sci 2022; 9:vetsci9100516. [PMID: 36288129 PMCID: PMC9609818 DOI: 10.3390/vetsci9100516] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/14/2022] [Accepted: 09/19/2022] [Indexed: 02/07/2023] Open
Abstract
Nonhuman primates (NHPs) are the closest living relatives of humans and play a critical and unique role in neuroscience research and pharmaceutical development. General anesthesia is usually required in neuroimaging studies of NHPs to keep the animal from stress and motion. However, the adverse effects of anesthesia on cerebral physiology and neural activity are pronounced and can compromise the data collection and interpretation. Functional connectivity is frequently examined using resting-state functional MRI (rsfMRI) to assess the functional abnormality in the animal brain under anesthesia. The fMRI signal can be dramatically suppressed by most anesthetics in a dose-dependent manner. In addition, rsfMRI studies may be further compromised by inter-subject variations when the sample size is small (as seen in most neuroscience studies of NHPs). Therefore, proper use of anesthesia is strongly demanded to ensure steady and consistent physiology maintained during rsfMRI data collection of each subject. The aim of this review is to summarize typical anesthesia used in rsfMRI scans of NHPs and the effects of anesthetics on cerebral physiology and functional connectivity. Moreover, the protocols with optimal rsfMRI data acquisition and anesthesia procedures for functional connectivity study of macaque monkeys are introduced.
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Affiliation(s)
- Xiaodong Zhang
- EPC Imaging Center and Division of Neuropharmacology and Neurologic Diseases, Emory National Primate Research Center, Emory University, 954 Gatewood RD, Atlanta, GA 30329, USA
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Ponton E, Turecki G, Nagy C. Sex Differences in the Behavioral, Molecular, and Structural Effects of Ketamine Treatment in Depression. Int J Neuropsychopharmacol 2021; 25:75-84. [PMID: 34894233 PMCID: PMC8756094 DOI: 10.1093/ijnp/pyab082] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 10/08/2021] [Accepted: 11/15/2021] [Indexed: 12/14/2022] Open
Abstract
Major depressive disorder (MDD) is a common psychiatric illness that manifests in sex-influenced ways. Men and women may experience depression differently and also respond to various antidepressant treatments in sex-influenced ways. Ketamine, which is now being used as a rapid-acting antidepressant, is likely the same. To date, the majority of studies investigating treatment outcomes in MDD do not disaggregate the findings in males and females, and this is also true for ketamine. This review aims to highlight that gap by exploring pre-clinical data-at a behavioral, molecular, and structural level-and recent clinical trials. Sex hormones, particularly estrogen and progesterone, influence the response at all levels examined, and sex is therefore a critical factor to examine when looking at ketamine response. Taken together, the data show females are more sensitive to ketamine than males, and it might be possible to monitor the phase of the menstrual cycle to mitigate some risks associated with the use of ketamine for females with MDD. Based on the studies reviewed in this article, we suggest that ketamine should be administered adhering to sex-specific considerations.
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Affiliation(s)
- Ethan Ponton
- Department of Anatomy and Cell Biology, McGill University, Montreal, Canada
| | - Gustavo Turecki
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Montreal, Canada
- Department of Psychiatry, McGill University, Montreal, Canada
| | - Corina Nagy
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Montreal, Canada
- Department of Psychiatry, McGill University, Montreal, Canada
- Correspondence: Corina Nagy, PhD, 6875 LaSalle Blvd, Verdun, Québec, Canada H4H 1R3 ()
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Alexander L, Jelen LA, Mehta MA, Young AH. The anterior cingulate cortex as a key locus of ketamine's antidepressant action. Neurosci Biobehav Rev 2021; 127:531-554. [PMID: 33984391 DOI: 10.1016/j.neubiorev.2021.05.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 05/02/2021] [Accepted: 05/03/2021] [Indexed: 12/30/2022]
Abstract
The subdivisions of the anterior cingulate cortex (ACC) - including subgenual, perigenual and dorsal zones - are implicated in the etiology, pathogenesis and treatment of major depression. We review an emerging body of evidence which suggests that changes in ACC activity are critically important in mediating the antidepressant effects of ketamine, the prototypical member of an emerging class of rapidly acting antidepressants. Infusions of ketamine induce acute (over minutes) and post-acute (over hours to days) modulations in subgenual and perigenual activity, and importantly, these changes can correlate with antidepressant efficacy. The subgenual and dorsal zones of the ACC have been specifically implicated in ketamine's anti-anhedonic effects. We emphasize the synergistic relationship between neuroimaging studies in humans and brain manipulations in animals to understand the causal relationship between changes in brain activity and therapeutic efficacy. We conclude with circuit-based perspectives on ketamine's action: first, related to ACC function in a central network mediating affective pain, and second, related to its role as the anterior node of the default mode network.
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Affiliation(s)
- Laith Alexander
- Department of Psychological Medicine, School of Academic Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom; St Thomas' Hospital, London, United Kingdom.
| | - Luke A Jelen
- Department of Psychological Medicine, School of Academic Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom; South London and Maudsley NHS Foundation Trust, London, United Kingdom
| | - Mitul A Mehta
- Department of Psychological Medicine, School of Academic Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Allan H Young
- Department of Psychological Medicine, School of Academic Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom; South London and Maudsley NHS Foundation Trust, London, United Kingdom
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Li CX, Kempf D, Howell L, Zhang X. Effects of alfaxalone on cerebral blood flow and intrinsic neural activity of rhesus monkeys: A comparison study with ketamine. Magn Reson Imaging 2020; 75:134-140. [PMID: 33127411 DOI: 10.1016/j.mri.2020.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 10/22/2020] [Accepted: 10/23/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Alfaxalone has been used increasingly in biomedical research and veterinary medicine of large animals in recent years. However, its effects on the cerebral blood flow (CBF) physiology and intrinsic neuronal activity of anesthetized brains remain poorly understood. METHODS Four healthy adult rhesus monkeys were anesthetized initially with alfaxalone (0.125 mg/kg/min) or ketamine (1.6 mg/kg/min) for 50 min, then administrated with 0.8% isoflurane for 60 min. Heart rates, breathing beats, and blood pressures were continuously monitored. CBF data were collected using pseudo-continuous arterial spin-labeling (pCASL) MRI technique and rsfMRI data were collected using single-shot EPI sequence for each anesthetic. RESULTS Both the heart rates and mean arterial pressure (MAP) remained more stable during alfaxalone infusion than those during ketamine administration. Alfaxalone reduced CBF substantially compared to ketamine anesthesia (grey matter, 65 ± 22 vs. 179 ± 38 ml/100g/min, p<0.001; white matter, 14 ± 7 vs. 26 ± 6 ml/100g/min, p < 0.05); In addition, CBF increase was seen in all selected cortical and subcortical regions of alfaxalone-pretreated monkey brains during isoflurane exposure, very different from the findings in isoflurane-exposed monkeys pretreated with ketamine. Also, alfaxalone showed suppression effects on functional connectivity of the monkey brain similar to ketamine. CONCLUSION Alfaxalone showed strong suppression effects on CBF of the monkey brain.The residual effect of alfaxalone on CBF of isoflurane-exposed brains was evident and monotonous in all the examined brain regions when used as induction agent for inhalational anesthesia. In particular, alfaxalone showed similar suppression effect on intrinsic neuronal activity of the brain in comparison with ketamine. These findings suggest alfaxalone can be a good alternative to veterinary anesthesia in neuroimaging examination of large animal models. However, its effects on CBF and functional connectivity should be considered.
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Affiliation(s)
- Chun-Xia Li
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States
| | - Doty Kempf
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States
| | - Leonard Howell
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States
| | - Xiaodong Zhang
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States; Division of Neuropharmacology and Neurologic Diseases, Yerkes National Primate Research Center, Emory University, Atlanta, GA 30329, United States.
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McMillan R, Muthukumaraswamy SD. The neurophysiology of ketamine: an integrative review. Rev Neurosci 2020; 31:457-503. [DOI: 10.1515/revneuro-2019-0090] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 01/26/2020] [Indexed: 12/13/2022]
Abstract
AbstractThe drug ketamine has been extensively studied due to its use in anaesthesia, as a model of psychosis and, most recently, its antidepressant properties. Understanding the physiology of ketamine is complex due to its rich pharmacology with multiple potential sites at clinically relevant doses. In this review of the neurophysiology of ketamine, we focus on the acute effects of ketamine in the resting brain. We ascend through spatial scales starting with a complete review of the pharmacology of ketamine and then cover its effects on in vitro and in vivo electrophysiology. We then summarise and critically evaluate studies using EEG/MEG and neuroimaging measures (MRI and PET), integrating across scales where possible. While a complicated and, at times, confusing picture of ketamine’s effects are revealed, we stress that much of this might be caused by use of different species, doses, and analytical methodologies and suggest strategies that future work could use to answer these problems.
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Affiliation(s)
- Rebecca McMillan
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Suresh D. Muthukumaraswamy
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Examining fMRI time-series entropy as a marker for brain E/I balance with pharmacological neuromodulation in a non-human primate translational model. Neurosci Lett 2020; 728:134984. [PMID: 32315710 DOI: 10.1016/j.neulet.2020.134984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 04/02/2020] [Accepted: 04/13/2020] [Indexed: 11/23/2022]
Abstract
Recently, there has been a lot of interest in the neuroimaging community in exploring fMRI time-series measures of local neuronal activity and excitation/inhibition (E/I) balance in the brain. In this preliminary study we probed the sensitivity of widely used sample entropy (SE) measure at multiple scales to controlled alteration of the brain's E/I balance in non-human primates (NHPs) with a well-characterized sub-anesthetic ketamine infusion fMRI model. We found that SE failed to detect the expected changes in E/I balance induced by ketamine. Subsequently, noticing that the complexity in the time series contributing SE could be dominated by non-neuronal noise in this experimental setting, we developed a new time-series measure called restricted sample entropy (RSE) by restricting SE estimations to regular portions of the fMRI time-series. RSE was able to adequately reflect the increased excitatory activity engendered by disinhibition of glutamergic neurons, through sub-anesthetic ketamine infusion. These results show that RSE is potentially a powerful tool for examining local neural activity, E/I balance, and alterations in brain state.
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Dynamics of Ketamine-induced Loss and Return of Consciousness across Primate Neocortex. Anesthesiology 2020; 132:750-762. [DOI: 10.1097/aln.0000000000003159] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Abstract
Background
Ketamine is a noncompetitive N-methyl-d-aspartate antagonist and is known for unique electrophysiologic profiles in electroencephalography. However, the mechanisms of ketamine-induced unconsciousness are not clearly understood. The authors have investigated neuronal dynamics of ketamine-induced loss and return of consciousness and how multisensory processing is modified in the primate neocortex.
Methods
The authors performed intracortical recordings of local field potentials and single unit activity during ketamine-induced altered states of consciousness in a somatosensory and ventral premotor network. The animals were trained to perform a button holding task to indicate alertness. Air puff to face or sound was randomly delivered in each trial regardless of their behavioral response. Ketamine was infused for 60 min.
Results
Ketamine-induced loss of consciousness was identified during a gradual evolution of the high beta-gamma oscillations. The slow oscillations appeared to develop at a later stage of ketamine anesthesia. Return of consciousness and return of preanesthetic performance level (performance return) were observed during a gradual drift of the gamma oscillations toward the beta frequency. Ketamine-induced loss of consciousness, return of consciousness, and performance return are all identified during a gradual change of the dynamics, distinctive from the abrupt neural changes at propofol-induced loss of consciousness and return of consciousness. Multisensory responses indicate that puff evoked potentials and single-unit firing responses to puff were both preserved during ketamine anesthesia, but sound responses were selectively diminished. Units with suppressed responses and those with bimodal responses appeared to be inhibited under ketamine and delayed in recovery.
Conclusions
Ketamine generates unique intracortical dynamics during its altered states of consciousness, suggesting fundamentally different neuronal processes from propofol. The gradually shifting dynamics suggest a continuously conscious or dreaming state while unresponsive under ketamine until its deeper stage with the slow-delta oscillations. Somatosensory processing is preserved during ketamine anesthesia, but multisensory processing appears to be diminished under ketamine and through recovery.
Editor’s Perspective
What We Already Know about This Topic
What This Article Tells Us That Is New
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Krajcovic B, Fajnerova I, Horacek J, Kelemen E, Kubik S, Svoboda J, Stuchlik A. Neural and neuronal discoordination in schizophrenia: From ensembles through networks to symptoms. Acta Physiol (Oxf) 2019; 226:e13282. [PMID: 31002202 DOI: 10.1111/apha.13282] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 03/27/2019] [Accepted: 04/12/2019] [Indexed: 12/22/2022]
Abstract
Despite the substantial knowledge accumulated by past research, the exact mechanisms of the pathogenesis of schizophrenia and causal treatments still remain unclear. Deficits of cognition and information processing in schizophrenia are today often viewed as the primary and core symptoms of this devastating disorder. These deficits likely result from disruptions in the coordination of neuronal and neural activity. The aim of this review is to bring together convergent evidence of discoordinated brain circuits in schizophrenia at multiple levels of resolution, ranging from principal cells and interneurons, neuronal ensembles and local circuits, to large-scale brain networks. We show how these aberrations could underlie deficits in cognitive control and other higher order cognitive-behavioural functions. Converging evidence from both animal models and patients with schizophrenia is presented in an effort to gain insight into common features of deficits in the brain information processing in this disorder, marked by disruption of several neurotransmitter and signalling systems and severe behavioural outcomes.
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Affiliation(s)
- Branislav Krajcovic
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
- Third Faculty of Medicine Charles University Prague Czech Republic
| | - Iveta Fajnerova
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
- Research Programme 3 - Applied Neurosciences and Brain Imaging National Institute of Mental Health Klecany Czech Republic
| | - Jiri Horacek
- Third Faculty of Medicine Charles University Prague Czech Republic
- Research Programme 3 - Applied Neurosciences and Brain Imaging National Institute of Mental Health Klecany Czech Republic
| | - Eduard Kelemen
- Research Programme 1 - Experimental Neurobiology National Institute of Mental Health Klecany Czech Republic
| | - Stepan Kubik
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Jan Svoboda
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Ales Stuchlik
- Department of Neurophysiology of Memory Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
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Maltbie EA, Gopinath KS, Howell LL. Effects of ketamine treatment on cocaine-induced reinstatement and disruption of functional connectivity in unanesthetized rhesus monkeys. Psychopharmacology (Berl) 2019; 236:2105-2118. [PMID: 30879118 DOI: 10.1007/s00213-019-05204-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 02/18/2019] [Indexed: 01/28/2023]
Abstract
RATIONALE Substance use disorders are characterized by a loss of executive control over reward-based decision-making, and disruption of fronto-striatal connectivity has been implicated in this process. Sub-anesthetic ketamine has recently been shown to bolster fronto-striatal connectivity in drug-naïve subjects. OBJECTIVES The influence of ketamine treatment was examined on the disruptive effects of cocaine on functional connectivity (FC) and on cocaine-seeking behavior in female rhesus monkeys. METHODS Three female rhesus were trained for unanesthetized MRI scanning. Each received three drug-naïve/abstinent pharmacological MRI scans with acute injections of saline, cocaine (0.3 mg/kg i.v.), and cocaine (0.3 mg/kg i.v.) 48-h after a ketamine treatment (low dose = 0.345 mg/kg bolus + 0.256 mg/kg/h for 1 h; i.v.), and a fourth scan with saline injection following 2 months of daily cocaine self-administration. A separate cohort of five rhesus (4 female), all with extensive histories of cocaine exposure, underwent reinstatement testing 48 h after ketamine (or vehicle) treatment. Two sub-anesthetic doses were tested: low dose and high dose = 0.69 mg/kg + 0.512 mg/kg/h for 1 h. RESULTS Ketamine treatment attenuated the effects of cocaine on both global and fronto-striatal FC in drug-naïve/abstinent subjects. Two months of daily cocaine self-administration led to prolonged disruption of both global and fronto-striatal FC. Cocaine-seeking behavior during reinstatement was reduced following ketamine treatment at the low dose, but not high dose. CONCLUSION These findings illustrate the disruptive effects of cocaine on functional connectivity and provide evidence for the potential efficacy of ketamine as a treatment for stimulant use disorder.
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Affiliation(s)
- Eric A Maltbie
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd NE, Atlanta, GA, 30329, USA
| | - Kaundinya S Gopinath
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd NE, Atlanta, GA, 30329, USA.,Department of Radiology and Imaging Sciences, Emory University, Atlanta, GA, 30329, USA
| | - Leonard L Howell
- Yerkes National Primate Research Center, Emory University, 954 Gatewood Rd NE, Atlanta, GA, 30329, USA. .,Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, 30329, USA.
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Ketamine and pharmacological imaging: use of functional magnetic resonance imaging to evaluate mechanisms of action. Behav Pharmacol 2018; 28:610-622. [PMID: 29049083 DOI: 10.1097/fbp.0000000000000354] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Ketamine has been used as a pharmacological model for schizophrenia as subanesthetic infusions have been shown to produce temporary schizophrenia-like symptoms in healthy humans. More recently, ketamine has emerged as a potential treatment for multiple psychiatric disorders, including treatment-resistant depression and suicidal ideation. However, the mechanisms underlying both the psychotomimetic and the therapeutic effects of ketamine remain poorly understood. This review provides an overview of what is known of the neural mechanisms underlying the effects of ketamine and details what functional MRI studies have yielded at a systems level focused on brain circuitry. Multiple analytic approaches show that ketamine exerts robust and consistent effects at the whole-brain level. These effects are highly conserved across human and nonhuman primates, validating the use of nonhuman primate models for further investigations with ketamine. Regional analysis of brain functional connectivity suggests that the therapeutic potential of ketamine may be derived from a strengthening of executive control circuitry, making it an intriguing candidate for the treatment of drug abuse. There are still important questions about the mechanism of action and the therapeutic potential of ketamine that can be addressed using appropriate functional neuroimaging techniques.
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Miller OH, Bruns A, Ben Ammar I, Mueggler T, Hall BJ. Synaptic Regulation of a Thalamocortical Circuit Controls Depression-Related Behavior. Cell Rep 2018; 20:1867-1880. [PMID: 28834750 DOI: 10.1016/j.celrep.2017.08.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 07/08/2017] [Accepted: 07/26/2017] [Indexed: 01/06/2023] Open
Abstract
The NMDA receptor (NMDAR) antagonist ketamine elicits a long-lasting antidepressant response in patients with treatment-resistant depression. Understanding how antagonism of NMDARs alters synapse and circuit function is pivotal to developing circuit-based therapies for depression. Using virally induced gene deletion, ex vivo optogenetic-assisted circuit analysis, and in vivo chemogenetics and fMRI, we assessed the role of NMDARs in the medial prefrontal cortex (mPFC) in controlling depression-related behavior in mice. We demonstrate that post-developmental genetic deletion of the NMDAR subunit GluN2B from pyramidal neurons in the mPFC enhances connectivity between the mPFC and limbic thalamus, but not the ventral hippocampus, and reduces depression-like behavior. Using intersectional chemogenetics, we show that activation of this thalamocortical circuit is sufficient to elicit a decrease in despair-like behavior. Our findings reveal that GluN2B exerts input-specific control of pyramidal neuron innervation and identify a medial dorsal thalamus (MDT)→mPFC circuit that controls depression-like behavior.
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Affiliation(s)
- Oliver H Miller
- Roche Innovation Center Basel, Basel 4070, Switzerland; Tulane Brain Institute, Tulane University, New Orleans, LA 70115, USA
| | - Andreas Bruns
- Roche Innovation Center Basel, Basel 4070, Switzerland
| | - Imen Ben Ammar
- Faculté de Médecine, Université de Strasbourg, Strasbourg 67000, France
| | | | - Benjamin J Hall
- Roche Innovation Center Basel, Basel 4070, Switzerland; Tulane Brain Institute, Tulane University, New Orleans, LA 70115, USA.
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13
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Li CSR, Zhang S, Hung CC, Chen CM, Duann JR, Lin CP, Lee TSH. Depression in chronic ketamine users: Sex differences and neural bases. Psychiatry Res 2017; 269:1-8. [PMID: 28892733 PMCID: PMC5634929 DOI: 10.1016/j.pscychresns.2017.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/16/2017] [Accepted: 09/01/2017] [Indexed: 01/10/2023]
Abstract
Chronic ketamine use leads to cognitive and affective deficits including depression. Here, we examined sex differences and neural bases of depression in chronic ketamine users. Compared to non-drug using healthy controls (HC), ketamine-using females but not males showed increased depression score as assessed by the Center of Epidemiological Studies Depression Scale (CES-D). We evaluated resting state functional connectivity (rsFC) of the subgenual anterior cingulate cortex (sgACC), a prefrontal structure consistently implicated in the pathogenesis of depression. Compared to HC, ketamine users (KU) did not demonstrate significant changes in sgACC connectivities at a corrected threshold. However, in KU, a linear regression against CES-D score showed less sgACC connectivity to the orbitofrontal cortex (OFC) with increasing depression severity. Examined separately, male and female KU showed higher sgACC connectivity to bilateral superior temporal gyrus and dorsomedial prefrontal cortex (dmPFC), respectively, in correlation with depression. The linear correlation of sgACC-OFC and sgACC-dmPFC connectivity with depression was significantly different in slope between KU and HC. These findings highlighted changes in rsFC of the sgACC as associated with depression and sex differences in these changes in chronic ketamine users.
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Affiliation(s)
- Chiang-Shan R Li
- Department of Psychiatry, Yale University, New Haven, CT, USA; Department of Neuroscience, Yale University, New Haven, CT, USA; Beijing Huilongguan Hospital, Beijing, China.
| | - Sheng Zhang
- Department of Psychiatry, Yale University, New Haven, CT, USA
| | - Chia-Chun Hung
- Bali Psychiatric Center, Ministry of Health and Welfare, Taiwan
| | - Chun-Ming Chen
- Department of Radiology, China Medical University Hospital, Taichung, Taiwan
| | - Jeng-Ren Duann
- Institute of Cognitive Neuroscience, National Central University, Taoyuan, Taiwan; Institute for Neural Computation, University of California San Diego, La Jolla, CA, USA
| | - Ching-Po Lin
- Institute of Neuroscience, National Yang Ming University, Taipei, Taiwan
| | - Tony Szu-Hsien Lee
- Department of Health Promotion and Health Education, National Taiwan Normal University, Taipei, Taiwan.
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Dauvermann MR, Lee G, Dawson N. Glutamatergic regulation of cognition and functional brain connectivity: insights from pharmacological, genetic and translational schizophrenia research. Br J Pharmacol 2017. [PMID: 28626937 DOI: 10.1111/bph.13919] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The pharmacological modulation of glutamatergic neurotransmission to improve cognitive function has been a focus of intensive research, particularly in relation to the cognitive deficits seen in schizophrenia. Despite this effort, there has been little success in the clinical use of glutamatergic compounds as procognitive drugs. Here, we review a selection of the drugs used to modulate glutamatergic signalling and how they impact on cognitive function in rodents and humans. We highlight how glutamatergic dysfunction, and NMDA receptor hypofunction in particular, is a key mechanism contributing to the cognitive deficits observed in schizophrenia and outline some of the glutamatergic targets that have been tested as putative procognitive targets for this disorder. Using translational research in this area as a leading exemplar, namely, models of NMDA receptor hypofunction, we discuss how the study of functional brain network connectivity can provide new insight into how the glutamatergic system impacts on cognitive function. Future studies characterizing functional brain network connectivity will increase our understanding of how glutamatergic compounds regulate cognition and could contribute to the future success of glutamatergic drug validation. Linked Articles This article is part of a themed section on Pharmacology of Cognition: a Panacea for Neuropsychiatric Disease? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.19/issuetoc.
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Affiliation(s)
- Maria R Dauvermann
- School of Psychology, National University of Ireland, Galway, Ireland.,McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Graham Lee
- McGovern Institute for Brain Research, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Neil Dawson
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, Lancaster University, Lancaster, UK
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