151
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Owesson-White CA, Roitman MF, Sombers LA, Belle AM, Keithley RB, Peele JL, Carelli RM, Wightman RM. Sources contributing to the average extracellular concentration of dopamine in the nucleus accumbens. J Neurochem 2012; 121:252-62. [PMID: 22296263 PMCID: PMC3323736 DOI: 10.1111/j.1471-4159.2012.07677.x] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Mesolimbic dopamine neurons fire in both tonic and phasic modes resulting in detectable extracellular levels of dopamine in the nucleus accumbens (NAc). In the past, different techniques have targeted dopamine levels in the NAc to establish a basal concentration. In this study, we used in vivo fast scan cyclic voltammetry (FSCV) in the NAc of awake, freely moving rats. The experiments were primarily designed to capture changes in dopamine caused by phasic firing - that is, the measurement of dopamine 'transients'. These FSCV measurements revealed for the first time that spontaneous dopamine transients constitute a major component of extracellular dopamine levels in the NAc. A series of experiments were designed to probe regulation of extracellular dopamine. Lidocaine was infused into the ventral tegmental area, the site of dopamine cell bodies, to arrest neuronal firing. While there was virtually no instantaneous change in dopamine concentration, longer sampling revealed a decrease in dopamine transients and a time-averaged decrease in the extracellular level. Dopamine transporter inhibition using intravenous GBR12909 injections increased extracellular dopamine levels changing both frequency and size of dopamine transients in the NAc. To further unmask the mechanics governing extracellular dopamine levels we used intravenous injection of the vesicular monoamine transporter (VMAT2) inhibitor, tetrabenazine, to deplete dopamine storage and increase cytoplasmic dopamine in the nerve terminals. Tetrabenazine almost abolished phasic dopamine release but increased extracellular dopamine to ∼500 nM, presumably by inducing reverse transport by dopamine transporter (DAT). Taken together, data presented here show that average extracellular dopamine in the NAc is low (20-30 nM) and largely arises from phasic dopamine transients.
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Affiliation(s)
- CA Owesson-White
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - MF Roitman
- Department of Psychology, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - LA Sombers
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - AM Belle
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - RB Keithley
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - JL Peele
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - RM Carelli
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - RM Wightman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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152
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Enoksson T, Bertran-Gonzalez J, Christie MJ. Nucleus accumbens D2- and D1-receptor expressing medium spiny neurons are selectively activated by morphine withdrawal and acute morphine, respectively. Neuropharmacology 2012; 62:2463-71. [PMID: 22410393 DOI: 10.1016/j.neuropharm.2012.02.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 01/23/2012] [Accepted: 02/21/2012] [Indexed: 11/28/2022]
Abstract
Opioids are effective analgesic agents but serious adverse effects such as tolerance and withdrawal contribute to opioid dependence and limit their use. Opioid withdrawal involves numerous brain regions and includes suppression of dopamine release and activation of neurons in the ventral striatum. By contrast, acute opioids increase dopamine release. Like withdrawal, acute opioids also activate neurons in the ventral striatum, suggesting that different populations of ventral striatal neurons may be activated by withdrawal and acute opioid actions. Here, immunofluorescence for the activity-related immediate-early gene, c-Fos, was examined in transgenic reporter mouse lines by confocal microscopy to study the specific populations of ventral striatal neurons activated by morphine withdrawal and acute morphine. After chronic morphine, naloxone-precipitated withdrawal strongly increased expression of c-Fos immunoreactivity, predominantly in D2-receptor (D2R) medium-sized spiny neurons (MSNs) of the nucleus accumbens (NAc) core and shell regions. By contrast, a single injection of morphine exclusively activated c-Fos immunoreactivity in D1-receptor expressing (D1R) MSNs of the core and shell of the NAc. These results reveal a striking segregation of neuronal responses occurring in the two populations of MSNs of the NAc in response to morphine withdrawal and acute morphine.
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Affiliation(s)
- T Enoksson
- Brain and Mind Research Institute, The University of Sydney, NSW 2006, Australia
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153
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Humphries MD, Khamassi M, Gurney K. Dopaminergic Control of the Exploration-Exploitation Trade-Off via the Basal Ganglia. Front Neurosci 2012; 6:9. [PMID: 22347155 PMCID: PMC3272648 DOI: 10.3389/fnins.2012.00009] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Accepted: 01/15/2012] [Indexed: 11/13/2022] Open
Abstract
We continuously face the dilemma of choosing between actions that gather new information or actions that exploit existing knowledge. This "exploration-exploitation" trade-off depends on the environment: stability favors exploiting knowledge to maximize gains; volatility favors exploring new options and discovering new outcomes. Here we set out to reconcile recent evidence for dopamine's involvement in the exploration-exploitation trade-off with the existing evidence for basal ganglia control of action selection, by testing the hypothesis that tonic dopamine in the striatum, the basal ganglia's input nucleus, sets the current exploration-exploitation trade-off. We first advance the idea of interpreting the basal ganglia output as a probability distribution function for action selection. Using computational models of the full basal ganglia circuit, we showed that, under this interpretation, the actions of dopamine within the striatum change the basal ganglia's output to favor the level of exploration or exploitation encoded in the probability distribution. We also found that our models predict striatal dopamine controls the exploration-exploitation trade-off if we instead read-out the probability distribution from the target nuclei of the basal ganglia, where their inhibitory input shapes the cortical input to these nuclei. Finally, by integrating the basal ganglia within a reinforcement learning model, we showed how dopamine's effect on the exploration-exploitation trade-off could be measurable in a forced two-choice task. These simulations also showed how tonic dopamine can appear to affect learning while only directly altering the trade-off. Thus, our models support the hypothesis that changes in tonic dopamine within the striatum can alter the exploration-exploitation trade-off by modulating the output of the basal ganglia.
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Affiliation(s)
- Mark D Humphries
- Group for Neural Theory, Department d'Etudes Cognitives, École Normale Supérieure Paris, France
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154
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Effects of apomorphine and β-carbolines on firing rate of neurons in the ventral pallidum in the rats. Behav Brain Res 2012; 227:109-15. [DOI: 10.1016/j.bbr.2011.10.041] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 10/23/2011] [Accepted: 10/25/2011] [Indexed: 11/22/2022]
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155
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Measuring Dopamine Synaptic Transmission with Molecular Imaging and Pharmacological Challenges: The State of the Art. MOLECULAR IMAGING IN THE CLINICAL NEUROSCIENCES 2012. [DOI: 10.1007/7657_2012_45] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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156
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Rice ME, Patel JC, Cragg SJ. Dopamine release in the basal ganglia. Neuroscience 2011; 198:112-37. [PMID: 21939738 PMCID: PMC3357127 DOI: 10.1016/j.neuroscience.2011.08.066] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/22/2011] [Accepted: 08/26/2011] [Indexed: 10/17/2022]
Abstract
Dopamine (DA) is a key transmitter in the basal ganglia, yet DA transmission does not conform to several aspects of the classic synaptic doctrine. Axonal DA release occurs through vesicular exocytosis and is action potential- and Ca²⁺-dependent. However, in addition to axonal release, DA neurons in midbrain exhibit somatodendritic release by an incompletely understood, but apparently exocytotic, mechanism. Even in striatum, axonal release sites are controversial, with evidence for DA varicosities that lack postsynaptic specialization, and largely extrasynaptic DA receptors and transporters. Moreover, DA release is often assumed to reflect a global response to a population of activities in midbrain DA neurons, whether tonic or phasic, with precise timing and specificity of action governed by other basal ganglia circuits. This view has been reinforced by anatomical evidence showing dense axonal DA arbors throughout striatum, and a lattice network formed by DA axons and glutamatergic input from cortex and thalamus. Nonetheless, localized DA transients are seen in vivo using voltammetric methods with high spatial and temporal resolution. Mechanistic studies using similar methods in vitro have revealed local regulation of DA release by other transmitters and modulators, as well as by proteins known to be disrupted in Parkinson's disease and other movement disorders. Notably, the actions of most other striatal transmitters on DA release also do not conform to the synaptic doctrine, with the absence of direct synaptic contacts for glutamate, GABA, and acetylcholine (ACh) on striatal DA axons. Overall, the findings reviewed here indicate that DA signaling in the basal ganglia is sculpted by cooperation between the timing and pattern of DA input and those of local regulatory factors.
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Affiliation(s)
- M E Rice
- Department of Neurosurgery, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
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157
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Rapid dopamine signaling differentially modulates distinct microcircuits within the nucleus accumbens during sucrose-directed behavior. J Neurosci 2011; 31:13860-9. [PMID: 21957248 DOI: 10.1523/jneurosci.1340-11.2011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The mesolimbic dopamine projection from the ventral tegmental area (VTA) to the nucleus accumbens (NAc) is critical in mediating reward-related behaviors, but the precise role of dopamine in this process remains unknown. We completed a series of studies to examine whether coincident changes occur in NAc cell firing and rapid dopamine release during goal-directed behaviors for sucrose and if so, to determine whether the two are causally linked. We show that distinct populations of NAc neurons differentially encode sucrose-directed behaviors, and using a combined electrophysiology/electrochemistry technique, further show that it is at those locations that rapid dopamine signaling is observed. To determine causality, NAc cell firing was recorded during selective pharmacological inactivation of dopamine burst firing using the NMDA receptor antagonist, AP-5. We show that phasic dopamine selectively modulates excitatory but not inhibitory responses of NAc neurons during sucrose-seeking behavior. Thus, rapid dopamine signaling does not exert global actions in the NAc but selectively modulates discrete NAc microcircuits that ultimately influence goal-directed actions.
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158
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The contribution of NMDA receptor signaling in the corticobasal ganglia reward network to appetitive Pavlovian learning. J Neurosci 2011; 31:11362-9. [PMID: 21813695 DOI: 10.1523/jneurosci.2411-11.2011] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
NMDA receptors (NMDARs) contribute to phasic transmission and synaptic plasticity and are thought to be important for learning. To better understand where NMDAR signaling is necessary for learning, we combined viral genetic strategies with genetic mouse models to investigate the contribution of NMDARs in the dopamine system to appetitive Pavlovian conditioning. NMDAR signaling in dopamine neurons was not required for Pavlovian conditioning; however, NMDARs in D(1) dopamine receptor (D(1)R)-expressing medium spiny neurons (MSNs), which receive input from dopamine neurons, were critical for this type of learning. NMDAR signaling was also required in brain regions that project to dopamine neurons, because removing NMDARs from afferent neurons to the ventral tegmental area (VTA) also prevented learning. This effect was likely attributable to loss of NMDAR signaling in the neurons of the prefrontal cortex (PFC), because learning could be restored in these animals by rescuing NMDAR expression in the PFC. Moreover, removing NMDARs exclusively from the PFC also prevented learning. Our findings suggest that NMDARs in neurons that project to and receive projections from the VTA are necessary for Pavlovian conditioning and specifically implicate the PFC and D(1)R-expressing MSNs in associative learning.
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159
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Kotowski SJ, Hopf FW, Seif T, Bonci A, von Zastrow M. Endocytosis promotes rapid dopaminergic signaling. Neuron 2011; 71:278-90. [PMID: 21791287 DOI: 10.1016/j.neuron.2011.05.036] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2011] [Indexed: 12/12/2022]
Abstract
D(1) dopamine receptors are primary mediators of dopaminergic signaling in the CNS. These receptors internalize rapidly following agonist-induced activation, but the functional significance of this process is unknown. We investigated D(1) receptor endocytosis and signaling in HEK293 cells and cultured striatal neurons using real-time fluorescence imaging and cAMP biosensor technology. Agonist-induced activation of D(1) receptors promoted endocytosis of receptors with a time course overlapping that of acute cAMP accumulation. Inhibiting receptor endocytosis blunted acute D(1) receptor-mediated signaling in both dissociated cells and striatal slice preparations. Although endocytic inhibition markedly attenuated acute cAMP accumulation, inhibiting the subsequent recycling of receptors had no effect. Further, D(1) receptors localized in close proximity to endomembrane-associated trimeric G protein and adenylyl cyclase immediately after endocytosis. Together, these results suggest a previously unanticipated role of endocytosis, and the early endocytic pathway, in supporting rapid dopaminergic neurotransmission.
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Affiliation(s)
- Sarah J Kotowski
- Department of Psychiatry and Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, CA 94158, USA
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160
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Kreitzer AC, Berke JD. Investigating striatal function through cell-type-specific manipulations. Neuroscience 2011; 198:19-26. [PMID: 21867745 DOI: 10.1016/j.neuroscience.2011.08.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 08/03/2011] [Accepted: 08/06/2011] [Indexed: 12/17/2022]
Abstract
The striatum integrates convergent input from the cortex, thalamus, and midbrain, and has a powerful influence over motivated behavior via outputs to downstream basal ganglia nuclei. Although the anatomy and physiology of distinct classes of striatal neurons have been intensively studied, the specific functions of these cell subpopulations have been more difficult to address. Recently, application of new methodologies for perturbing activity and signaling in different cell types in vivo has begun to allow direct tests of the causal roles of striatal neurons in behavior.
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Affiliation(s)
- A C Kreitzer
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA.
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161
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André VM, Fisher YE, Levine MS. Altered Balance of Activity in the Striatal Direct and Indirect Pathways in Mouse Models of Huntington's Disease. Front Syst Neurosci 2011; 5:46. [PMID: 21720523 PMCID: PMC3118454 DOI: 10.3389/fnsys.2011.00046] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 06/03/2011] [Indexed: 11/13/2022] Open
Abstract
Imbalance in the activity of striatal direct and indirect pathway neurons contributes to motor disturbances in several neurodegenerative diseases. In Huntington's disease (HD), indirect pathway [dopamine (DA) D2 receptor-expressing] medium-sized spiny neurons (MSNs) are believed to show earlier vulnerability than direct pathway MSNs. We examined synaptic activity and DA modulation in MSNs forming the direct and indirect pathways in YAC128 and BACHD mouse models of HD. To visualize the two types of MSNs, we used mice expressing enhanced green fluorescent protein under the control of the promoter for the DA D1 or D2 receptor. Experiments were performed in early symptomatic (1.5 months) and symptomatic (12 months) mice. Behaviorally, early symptomatic mice showed increased stereotypies while symptomatic mice showed decreased motor activity. Electrophysiologically, at the early stage, excitatory and inhibitory transmission onto D1-YAC128 and D1-BACHD MSNs were increased, while there was no change in D2 MSNs. DA modulation of spontaneous excitatory postsynaptic currents (sEPSCs) in slices was absent in YAC128 cells at the early stage, but was restored by treating the slices with the DA depleter tetrabenazine (TBZ). In BACHD mice TBZ restored paired-pulse ratios and a D1 receptor antagonist induced a larger decrease of sEPSCs than in D1-WT cells, suggesting increased DA tone. Finally, TBZ decreased stereotypies in BACHD mice. These results indicate that by reducing DA or antagonizing D1 receptors, increases in inhibitory and excitatory transmission in early phenotypic direct pathway neurons can be normalized. In symptomatic YAC128 mice, excitatory synaptic transmission onto D1 MSNs was decreased, while inhibitory transmission was increased in D2 MSNs. These studies provide evidence for differential and complex imbalances in glutamate and GABA transmission, as well as in DA modulation, in direct and indirect pathway MSNs during HD progression.
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Affiliation(s)
- Véronique M André
- Intellectual and Developmental Disabilities Research Center, Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, Semel Institute, University of California at Los Angeles Los Angeles, CA, USA
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162
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Palner M, Underwood MD, Kumar DJS, Arango V, Knudsen GM, John Mann J, Parsey RV. Ex vivo evaluation of the serotonin 1A receptor partial agonist [³H]CUMI-101 in awake rats. Synapse 2011; 65:715-23. [PMID: 21108237 DOI: 10.1002/syn.20888] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 11/11/2010] [Indexed: 11/11/2022]
Abstract
[³H]CUMI-101 is a 5-HT(1A) partial agonist, which has been evaluated for use as a positron emission tracer in baboon and humans. We sought to evaluate the properties of [³H]CUMI-101 ex vivo in awake rats and determine if [³H]CUMI-101 can measure changes in synaptic levels of serotonin after different challenge paradigms. [³H]CUMI-101 shows good uptake and good specific binding ratio (SBR) in frontal cortex 5.18 and in hippocampus 3.18. Binding was inhibited in a one-binding-site fashion by WAY100635 and unlabeled CUMI-101. The ex vivo B(max) of [³H]CUMI-101 in frontal cortex (98.7 fmol/mg) and hippocampus (131 fmol/kg) agree with the ex vivo B(max) of [³H]MPPF in frontal cortex (147.1 fmol/mg) and hippocampus (72.1 fmol/mg) and with in vitro values reported with 8-OH-DPAT. Challenges with citalopram, a selective serotonin reuptake inhibitor, fenfluramine, a serotonin releaser, and 4-chloro-DL-phenylalanine, a serotonin synthesis inhibitor, did not show any effect on the standardized uptake values (SUVs) in any region. Citalopram did alter SBR, but this was due to changes in cerebellar SUVs. Our results indicate that [³H]CUMI-101 is a good radioligand for imaging 5-HT(1A) high-density regions in rats; however, the results from pharmacological challenges remain inconclusive.
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Affiliation(s)
- Mikael Palner
- Division of Molecular Imaging and Neuropathology, New York State Psychiatric Institute, New York, New York, USA.
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163
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Hong S, Hikosaka O. Dopamine-mediated learning and switching in cortico-striatal circuit explain behavioral changes in reinforcement learning. Front Behav Neurosci 2011; 5:15. [PMID: 21472026 PMCID: PMC3065164 DOI: 10.3389/fnbeh.2011.00015] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Accepted: 03/09/2011] [Indexed: 11/13/2022] Open
Abstract
The basal ganglia are thought to play a crucial role in reinforcement learning. Central to the learning mechanism are dopamine (DA) D1 and D2 receptors located in the cortico-striatal synapses. However, it is still unclear how this DA-mediated synaptic plasticity is deployed and coordinated during reward-contingent behavioral changes. Here we propose a computational model of reinforcement learning that uses different thresholds of D1- and D2-mediated synaptic plasticity which are antagonized by DA-independent synaptic plasticity. A phasic increase in DA release caused by a larger-than-expected reward induces long-term potentiation (LTP) in the direct pathway, whereas a phasic decrease in DA release caused by a smaller-than-expected reward induces a cessation of long-term depression, leading to LTP in the indirect pathway. This learning mechanism can explain the robust behavioral adaptation observed in a location-reward-value-association task where the animal makes shorter latency saccades to reward locations. The changes in saccade latency become quicker as the monkey becomes more experienced. This behavior can be explained by a switching mechanism which activates the cortico-striatal circuit selectively. Our model also shows how D1- or D2-receptor blocking experiments affect selectively either reward or no-reward trials. The proposed mechanisms also explain the behavioral changes in Parkinson's disease.
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Affiliation(s)
- Simon Hong
- Laboratory of Sensorimotor Research, National Eye Institute, National Institutes of Health Bethesda, MD, USA
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164
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Moustafa AA, Gluck MA. Computational cognitive models of prefrontal-striatal-hippocampal interactions in Parkinson's disease and schizophrenia. Neural Netw 2011; 24:575-91. [PMID: 21411277 DOI: 10.1016/j.neunet.2011.02.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 01/22/2011] [Accepted: 02/17/2011] [Indexed: 11/29/2022]
Abstract
Disruption to different components of the prefrontal cortex, basal ganglia, and hippocampal circuits leads to various psychiatric and neurological disorders including Parkinson's disease (PD) and schizophrenia. Medications used to treat these disorders (such as levodopa, dopamine agonists, antipsychotics, among others) affect the prefrontal-striatal-hippocampal circuits in a complex fashion. We have built models of prefrontal-striatal and striatal-hippocampal interactions which simulate cognitive dysfunction in PD and schizophrenia. In these models, we argue that the basal ganglia is key for stimulus-response learning, the hippocampus for stimulus-stimulus representational learning, and the prefrontal cortex for stimulus selection during learning about multidimensional stimuli. In our models, PD is associated with reduced dopamine levels in the basal ganglia and prefrontal cortex. In contrast, the cognitive deficits in schizophrenia are associated primarily with hippocampal dysfunction, while the occurrence of negative symptoms is associated with frontostriatal deficits in a subset of patients. In this paper, we review our past models and provide new simulation results for both PD and schizophrenia. We also describe an extended model that includes simulation of the different functional role of D1 and D2 dopamine receptors in the basal ganglia and prefrontal cortex, a dissociation we argue is essential for understanding the non-uniform effects of levodopa, dopamine agonists, and antipsychotics on cognition. Motivated by clinical and physiological data, we discuss model limitations and challenges to be addressed in future models of these brain disorders.
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Affiliation(s)
- Ahmed A Moustafa
- Center for Molecular and Behavioral Neuroscience, Rutgers University-Newark, Newark, New Jersey 07102, USA.
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165
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Balanced NMDA receptor activity in dopamine D1 receptor (D1R)- and D2R-expressing medium spiny neurons is required for amphetamine sensitization. Proc Natl Acad Sci U S A 2011; 108:4206-11. [PMID: 21368124 DOI: 10.1073/pnas.1101424108] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Signaling through N-methyl-D-aspartate-type glutamate receptors (NMDARs) is essential for the development of behavioral sensitization to psychostimulants such as amphetamine (AMPH). However, the cell type and brain region in which NMDAR signaling is required for AMPH sensitization remain unresolved. Here we use selective inactivation of Grin1, the gene encoding the essential NR1 subunit of NMDARs, in dopamine neurons or their medium spiny neuron (MSN) targets, to address this issue. We show that NMDAR signaling in dopamine neurons is not required for behavioral sensitization to AMPH. Conversely, removing NMDARs from MSNs that express the dopamine D1 receptor (D1R) significantly attenuated AMPH sensitization, and conditional, virus-mediated restoration of NR1 in D1R neurons in the nucleus accumbens (NAc) of these animals rescued sensitization. Interestingly, sensitization could also be restored by virus-mediated inactivation of NR1 in all remaining neurons in the NAc of animals lacking NMDARs on D1R neurons, or by removing NMDARs from all MSNs. Taken together, these data indicate that unbalanced loss of NMDAR signaling in D1R MSNs alone prevents AMPH sensitization, whereas a balanced loss of NMDARs from both D1R and dopamine D2 receptor-expressing (D2R) MSNs is permissive for sensitization.
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166
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Young KA, Liu Y, Gobrogge KL, Dietz DM, Wang H, Kabbaj M, Wang Z. Amphetamine alters behavior and mesocorticolimbic dopamine receptor expression in the monogamous female prairie vole. Brain Res 2011; 1367:213-22. [PMID: 20933511 PMCID: PMC3143067 DOI: 10.1016/j.brainres.2010.09.109] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 09/29/2010] [Accepted: 09/30/2010] [Indexed: 11/20/2022]
Abstract
We have recently established the socially monogamous prairie vole (Microtus ochrogaster) as an animal model with which to investigate the involvement of mesocorticolimbic dopamine (DA) in the amphetamine (AMPH)-induced impairment of social behavior. As the majority of our work, to date, has focused on males, and sex differences are commonly reported in the behavioral and neurobiological responses to AMPH, the current study was designed to examine the behavioral and neurobiological effects of AMPH treatment in female prairie voles. We used a conditioned place preference (CPP) paradigm to determine a dose-response curve for the behavioral effects of AMPH in female prairie voles, and found that conditioning with low to intermediate (0.2 and 1.0 mg/kg), but not very low (0.1 mg/kg), doses of AMPH induced a CPP. We also found that exposure to a behaviorally relevant dose of AMPH (1.0 mg/kg) induced an increase in DA concentration in the nucleus accumbens (NAcc) and caudate putamen but not the medial prefrontal cortex or ventral tegmental area (VTA). Finally, repeated AMPH exposure (1.0 mg/kg once per day for 3 consecutive days; an injection paradigm that has been recently shown to alter DA receptor expression and impair social bonding in male prairie voles) increased D1, but not D2, receptor mRNA in the NAcc, and decreased D2 receptor mRNA and D2-like receptor binding in the VTA. Together, these data indicate that AMPH alters mesocorticolimbic DA neurotransmission in a region- and receptor-specific manner, which, in turn, could have profound consequences on social behavior in female prairie voles.
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Affiliation(s)
- Kimberly A. Young
- Department of Psychology, Florida State University, Tallahassee, FL 32306, USA
- Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA
| | - Yan Liu
- Department of Psychology, Florida State University, Tallahassee, FL 32306, USA
- Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA
| | - Kyle L. Gobrogge
- Department of Psychology, Florida State University, Tallahassee, FL 32306, USA
- Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA
| | - David M. Dietz
- Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Hui Wang
- Department of Psychology, Florida State University, Tallahassee, FL 32306, USA
- Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Mohamed Kabbaj
- Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA
| | - Zuoxin Wang
- Department of Psychology, Florida State University, Tallahassee, FL 32306, USA
- Program in Neuroscience, Florida State University, Tallahassee, FL 32306, USA
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167
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Koshikawa N, Fujita S, Adachi K. Behavioral pharmacology of orofacial movement disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2011; 97:1-38. [PMID: 21708305 DOI: 10.1016/b978-0-12-385198-7.00001-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dysfunction in orofacial movement is evident in patients with schizophrenia, Parkinson's disease and Huntington's disease. In animal studies on orofacial dyskinesia, these neurological disorders have been considered as a starting point to examine the pathophysiology and mechanisms underlying the symptoms. There is circumstantial evidence that orofacial dyskinesia in humans might be the consequence of hyperfunctioning mesolimbic-pallidal circuitry, in which the mesolimbic region occupies a central role, in contrast to typical Parkinson-like symptoms which involve hypofunction in the nigrostriato-nigral circuity. Studies in animals suffer from technical difficulties concerning the assessment of orofacial behaviors. There are some experimental designs that provide detailed information on the amplitude and the frequency of the jaw movements. By using such methods, the involvement of neurotransmitter systems and functional neural connections within the basal ganglia has been studied in rat rhythmical jaw movements. Regarding neurotransmitter systems, dopaminergic, cholinergic, γ-aminobutyric acid (GABA)ergic and glutamaterigic systems have been shown to be involved in rat rhythmical jaw movements. The involved neural connections have also been investigated, focusing on the differential role between the dorsal and ventral part of the striatum, the shell and core of the nucleus accumbens and the output pathways from the striatum and the nucleus accumbens. Taking available clinical and experimental evidence, the orofacial dyskinesias are thought to arise when hierarchically lower order output stations of the mesolimbic region start to dysfunction as a consequence of the arrival of distorted information sent by the mesolimbic region. This review seeks to provide an overview of prior and recent findings across several orofacial movement disorders and interpret new insights in the context of the limitations of behavioral pharmacology and prior knowledge of the regulation of behavior by dopamine receptors and other related neuronal systems.
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Affiliation(s)
- Noriaki Koshikawa
- Department of Pharmacology, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
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168
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Robinson DL, Zitzman DL, Williams SK. Mesolimbic dopamine transients in motivated behaviors: focus on maternal behavior. Front Psychiatry 2011; 2:23. [PMID: 21629844 PMCID: PMC3098725 DOI: 10.3389/fpsyt.2011.00023] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 04/23/2011] [Indexed: 11/13/2022] Open
Abstract
Phasic activity of the mesolimbic dopamine pathway - burst-firing of dopamine neurons and the resulting dopamine release events at striatal targets - have been associated with a variety of motivational events, such as novelty, salient stimuli, social interaction, and reward prediction. Over the past decade, advances in electrochemical techniques have allowed measurement of naturally occurring dopamine release events, or dopamine transients, in awake animals during ongoing behavior. Thus, a growing body of studies has revealed dynamic dopamine input to ventral striatum during motivated behavior in a variety of experimental paradigms. We propose that dopamine transients may be important neural signals in pup-directed aspects of maternal behavior, as preliminary data suggest that dopamine transients in dams are associated with pup cues. Measurements of dopamine transients may be useful to investigate not only typical maternal behavior but also maternal inattention induced by drug exposure or stress.
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Affiliation(s)
- Donita L Robinson
- Bowles Center for Alcohol Studies, University of North Carolina Chapel Hill, NC, USA
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169
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Calhoon GG, O'Donnell P. Many Roads to Motor Deficits: Loss of Dopamine Signaling in Direct or Indirect Basal Ganglia Pathway Leads to Akinesia through Distinct Physiological Mechanisms. Front Neurosci 2010; 4:168. [PMID: 21151744 PMCID: PMC3000179 DOI: 10.3389/fnins.2010.00168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Accepted: 08/27/2010] [Indexed: 11/13/2022] Open
Affiliation(s)
- Gwendolyn G Calhoon
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine Baltimore, MD, USA
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170
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XIIth international symposium on radiopharmaceutical chemistry: Abstracts and programme. J Labelled Comp Radiopharm 2010. [DOI: 10.1002/jlcr.2580400801] [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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171
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Mitochondrial abnormalities in the putamen in Parkinson's disease dyskinesia. Acta Neuropathol 2010; 120:623-31. [PMID: 20740286 DOI: 10.1007/s00401-010-0740-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 08/15/2010] [Accepted: 08/15/2010] [Indexed: 10/19/2022]
Abstract
Prolonged treatment of Parkinson's disease (PD) with levodopa leads to disabling side effects collectively referred to as 'dyskinesias'. We hypothesized that bioenergetic function in the putamen might play a crucial role in the development of dyskinesias. To test this hypothesis, we used post mortem samples of the human putamen and applied real time-PCR approaches and gene expression microarrays. We found that mitochondrial DNA (mtDNA) levels are decreased in patients who have developed dyskinesias, and mtDNA damage is concomitantly increased. These pathologies were not observed in PD subjects without signs of dyskinesias. The group of nuclear mRNA transcripts coding for the proteins of the mitochondrial electron transfer chain was decreased in patients with dyskinesias to a larger extent than in patients who had not developed dyskinesias. To examine whether dopamine fluctuations affect mtDNA levels in dopaminoceptive neurons, rat striatal neurons in culture were repeatedly exposed to levodopa, dopamine or their metabolites. MtDNA levels were reduced after treatment with dopamine, but not after treatment with dopamine metabolites. Levodopa led to an increase in mtDNA levels. We conclude that mitochondrial susceptibility in the putamen plays a role in the development of dyskinesias.
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172
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Pawlak V, Wickens JR, Kirkwood A, Kerr JND. Timing is not Everything: Neuromodulation Opens the STDP Gate. Front Synaptic Neurosci 2010; 2:146. [PMID: 21423532 PMCID: PMC3059689 DOI: 10.3389/fnsyn.2010.00146] [Citation(s) in RCA: 174] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 09/27/2010] [Indexed: 11/27/2022] Open
Abstract
Spike timing dependent plasticity (STDP) is a temporally specific extension of Hebbian associative plasticity that has tied together the timing of presynaptic inputs relative to the postsynaptic single spike. However, it is difficult to translate this mechanism to in vivo conditions where there is an abundance of presynaptic activity constantly impinging upon the dendritic tree as well as ongoing postsynaptic spiking activity that backpropagates along the dendrite. Theoretical studies have proposed that, in addition to this pre- and postsynaptic activity, a “third factor” would enable the association of specific inputs to specific outputs. Experimentally, the picture that is beginning to emerge, is that in addition to the precise timing of pre- and postsynaptic spikes, this third factor involves neuromodulators that have a distinctive influence on STDP rules. Specifically, neuromodulatory systems can influence STDP rules by acting via dopaminergic, noradrenergic, muscarinic, and nicotinic receptors. Neuromodulator actions can enable STDP induction or – by increasing or decreasing the threshold – can change the conditions for plasticity induction. Because some of the neuromodulators are also involved in reward, a link between STDP and reward-mediated learning is emerging. However, many outstanding questions concerning the relationship between neuromodulatory systems and STDP rules remain, that once solved, will help make the crucial link from timing-based synaptic plasticity rules to behaviorally based learning.
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Affiliation(s)
- Verena Pawlak
- Network Imaging Group, Max Planck Institute for Biological Cybernetics Tuebingen, Germany
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173
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Fabbricatore AT, Ghitza UE, Prokopenko VF, West MO. Electrophysiological evidence of mediolateral functional dichotomy in the rat nucleus accumbens during cocaine self-administration II: phasic firing patterns. Eur J Neurosci 2010; 31:1671-82. [PMID: 20525080 DOI: 10.1111/j.1460-9568.2010.07230.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In the cocaine self-administering rat, individual nucleus accumbens (NAcc) neurons exhibit phasic changes in firing rate within minutes and/or seconds of lever presses (i.e. slow phasic and rapid phasic changes, respectively). To determine whether neurons that demonstrate these changes during self-administration sessions are differentially distributed in the NAcc, rats were implanted with jugular catheters and microwire arrays in different NAcc subregions (core, dorsal shell, ventromedial shell, ventrolateral shell, or rostral pole). Neural recording sessions were typically conducted on days 13-17 of cocaine self-administration (0.77 mg/kg per 0.2-mL infusion; fixed-ratio 1 schedule of reinforcement; 6-h daily sessions). Pre-press rapid phasic firing rate changes were greater in lateral accumbal (core and ventrolateral shell) than in medial accumbal (dorsal shell and rostral pole shell) subregions. Slow phasic pattern analysis revealed that reversal latencies of neurons that exhibited change + reversal patterns differed mediolaterally: medial NAcc neurons exhibited more early reversals and fewer progressive/late reversals than lateral NAcc neurons. Comparisons of firing patterns within individual neurons across time bases indicated that lateral NAcc pre-press rapid phasic increases were correlated with tonic increases. Tonic decreases were correlated with slow phasic patterns in individual medial NAcc neurons, indicative of greater pharmacological sensitivity of neurons in this region. On the other hand, the bias of the lateral NAcc towards increased pre-press rapid phasic activity, coupled with a greater prevalence of tonic increase firing, may reflect particular sensitivity of these neurons to excitatory afferent signaling and perhaps differential pharmacological influences on firing rates between regions.
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Affiliation(s)
- Anthony T Fabbricatore
- Department of Psychology, Rutgers, the State University of New Jersey, Piscataway, NJ 08854, USA.
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174
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Wall VZ, Parker JG, Fadok JP, Darvas M, Zweifel L, Palmiter RD. A behavioral genetics approach to understanding D1 receptor involvement in phasic dopamine signaling. Mol Cell Neurosci 2010; 46:21-31. [PMID: 20888914 DOI: 10.1016/j.mcn.2010.09.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2010] [Accepted: 09/23/2010] [Indexed: 11/28/2022] Open
Abstract
Dopamine-producing neurons fire with both basal level tonic patterns and phasic bursts. Varying affinities of the five dopamine receptors have led to a hypothesis that higher affinity receptors are primarily activated by basal level tonic dopamine, while lower affinity receptors may be tuned to be sensitive to higher levels caused by phasic bursts. Genetically modified mice provide a method to begin to probe this hypothesis. Here we discuss three mouse models. Dopamine-deficient mice were used to determine which behaviors require dopamine. These behaviors were then analyzed in mice lacking D1 receptors and in mice with reduced phasic dopamine release. Comparison of the latter two mouse models revealed a similar failure to learn about and respond normally to cues that indicate either a positive or negative outcome, giving support to the hypothesis that phasic dopamine release and the D1 receptor act in the same pathway. However, the D1 receptor likely has additional roles beyond those of phasic dopamine detection, because D1 receptor knockout mice have deficits in addition to what has been observed in mice with reduced phasic dopamine release.
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Affiliation(s)
- Valerie Z Wall
- Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA
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175
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Absence of NMDA receptors in dopamine neurons attenuates dopamine release but not conditioned approach during Pavlovian conditioning. Proc Natl Acad Sci U S A 2010; 107:13491-6. [PMID: 20616081 DOI: 10.1073/pnas.1007827107] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
During Pavlovian conditioning, phasic dopamine (DA) responses emerge to reward-predictive stimuli as the subject learns to anticipate reward delivery. This observation has led to the hypothesis that phasic dopamine signaling is important for learning. To assess the ability of mice to develop anticipatory behavior and to characterize the contribution of dopamine, we used a food-reinforced Pavlovian conditioning paradigm. As mice learned the cue-reward association, they increased their head entries to the food receptacle in a pattern that was consistent with conditioned anticipatory behavior. D1-receptor knockout (D1R-KO) mice had impaired acquisition, and systemic administration of a D1R antagonist blocked both the acquisition and expression of conditioned approach in wild-type mice. To assess the specific contribution of phasic dopamine transmission, we tested mice lacking NMDA-type glutamate receptors (NMDARs) exclusively in dopamine neurons (NR1-KO mice). Surprisingly, NR1-KO mice learned at the same rate as their littermate controls. To evaluate the contribution of NMDARs to phasic dopamine release in this paradigm, we performed fast-scan cyclic voltammetry in the nucleus accumbens of awake mice. Despite having significantly attenuated phasic dopamine release following reward delivery, KO mice developed cue-evoked dopamine release at the same rate as controls. We conclude that NMDARs in dopamine neurons enhance but are not critical for phasic dopamine release to behaviorally relevant stimuli; furthermore, their contribution to phasic dopamine signaling is not necessary for the development of cue-evoked dopamine or anticipatory activity in a D1R-dependent Pavlovian conditioning paradigm.
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176
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Chen YI, Choi JK, Xu H, Ren J, Andersen SL, Jenkins BG. Pharmacologic neuroimaging of the ontogeny of dopamine receptor function. Dev Neurosci 2010; 32:125-38. [PMID: 20523024 DOI: 10.1159/000286215] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 02/09/2010] [Indexed: 01/23/2023] Open
Abstract
Characterization of the ontogeny of the cerebral dopaminergic system is crucial for gaining a greater understanding of normal brain development and its alterations in response to drugs of abuse or conditions such as attention-deficit hyperactivity disorder. Pharmacological MRI (phMRI) was used to determine the response to dopamine transporter (DAT) blockers cocaine and methylphenidate (MPH), the dopamine releaser D-amphetamine (AMPH), the selective D1 agonist dihydrexidine, and the D2/D3 agonist quinpirole in young (<30 days old) and adult (>60 days old) rats. In adult rats, cocaine (0.5 mg/kg i.v.) or MPH (2 mg/kg) induced primarily positive cerebral blood volume (rCBV) changes in the dopaminergic circuitry, but negative rCBV changes in the young animals. Microdialysis measurements in the striatum showed that young rats have a smaller increase in extracellular dopamine in response to cocaine than adults. The young rats showed little rCBV response to the selective D1 agonist dihydrexidine in contrast to robust rCBV increases observed in the adults, whereas there was a similar negative rCBV response in the young and adult rats to the D2 agonist quinpirole. We also performed a meta-analysis of literature data on the development of D1 and D2 receptors and the DAT. These data suggest a predominance of D2-like over D1-like function between 20 and 30 days of age. These combined results suggested that the dopamine D1 receptor is functionally inhibited at young age.
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Affiliation(s)
- Y Iris Chen
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA.
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177
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Distinct Roles of Synaptic Transmission in Direct and Indirect Striatal Pathways to Reward and Aversive Behavior. Neuron 2010; 66:896-907. [DOI: 10.1016/j.neuron.2010.05.011] [Citation(s) in RCA: 438] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2010] [Indexed: 11/24/2022]
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178
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Egerton A, Hirani E, Ahmad R, Turton DR, Brickute D, Rosso L, Howes OD, Luthra SK, Grasby PM. Further evaluation of the carbon11-labeled D(2/3) agonist PET radiotracer PHNO: reproducibility in tracer characteristics and characterization of extrastriatal binding. Synapse 2010; 64:301-12. [PMID: 19957364 DOI: 10.1002/syn.20718] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
[(11)C]-(+)-PHNO is a new dopamine D(2/3) receptor agonist radiotracer which has been successfully used to measure D(2/3) receptor availability in experimental animals and man. Here we report in vivo evaluation in the rat of the biodistribution, metabolism, specificity, selectivity, and dopamine sensitivity of carbon11-labeled PHNO ([(11)C]-3-PHNO) produced by an alternative radiochemical synthesis method. [(11)C]-3-PHNO showed rapid metabolism and clearance from most peripheral organs and tissues. [(11)C]-3-PHNO, but not its polar metabolite, readily crossed the blood-brain barrier and showed high levels of uptake in the D(2/3)-rich striatum. Pretreatment with unlabeled PHNO and the D(2/3) receptor antagonist raclopride indicated that binding in the striatum was specific and selective to D(2/3) receptors. PET studies in anesthetized rats revealed significant reductions in [(11)C]-3-PHNO binding in the striatum following amphetamine administration, indicating sensitivity to increases in endogenous dopamine concentrations. D(2/3) antagonist pretreatment additionally indicated moderate levels of [(11)C]-3-PHNO specific binding in several extrastriatal brain areas-most notably the olfactory bulbs and tubercles, thalamus, and hypothalamus. Of particular interest, approximately 30% of [(11)C]-3-PHNO signal in the cerebellum-a region often used as a "low-binding" reference region for PET quantification-was attributable to specific signal. These data demonstrate that [(11)C]-3-PHNO shows similar tracer characteristics to [(11)C]-(+)-PHNO, but additionally indicate that radiolabeled PHNO may be used to estimate D(2/3) receptor availability in select extrastriatal brain regions with PET.
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Affiliation(s)
- Alice Egerton
- Division of Neuroscience and Psychological Medicine, Department of Neuroscience and Mental Health, Imperial College London, London, United Kingdom.
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179
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Schultz W. Dopamine signals for reward value and risk: basic and recent data. Behav Brain Funct 2010; 6:24. [PMID: 20416052 PMCID: PMC2876988 DOI: 10.1186/1744-9081-6-24] [Citation(s) in RCA: 411] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 04/23/2010] [Indexed: 01/20/2023] Open
Abstract
Background Previous lesion, electrical self-stimulation and drug addiction studies suggest that the midbrain dopamine systems are parts of the reward system of the brain. This review provides an updated overview about the basic signals of dopamine neurons to environmental stimuli. Methods The described experiments used standard behavioral and neurophysiological methods to record the activity of single dopamine neurons in awake monkeys during specific behavioral tasks. Results Dopamine neurons show phasic activations to external stimuli. The signal reflects reward, physical salience, risk and punishment, in descending order of fractions of responding neurons. Expected reward value is a key decision variable for economic choices. The reward response codes reward value, probability and their summed product, expected value. The neurons code reward value as it differs from prediction, thus fulfilling the basic requirement for a bidirectional prediction error teaching signal postulated by learning theory. This response is scaled in units of standard deviation. By contrast, relatively few dopamine neurons show the phasic activation following punishers and conditioned aversive stimuli, suggesting a lack of relationship of the reward response to general attention and arousal. Large proportions of dopamine neurons are also activated by intense, physically salient stimuli. This response is enhanced when the stimuli are novel; it appears to be distinct from the reward value signal. Dopamine neurons show also unspecific activations to non-rewarding stimuli that are possibly due to generalization by similar stimuli and pseudoconditioning by primary rewards. These activations are shorter than reward responses and are often followed by depression of activity. A separate, slower dopamine signal informs about risk, another important decision variable. The prediction error response occurs only with reward; it is scaled by the risk of predicted reward. Conclusions Neurophysiological studies reveal phasic dopamine signals that transmit information related predominantly but not exclusively to reward. Although not being entirely homogeneous, the dopamine signal is more restricted and stereotyped than neuronal activity in most other brain structures involved in goal directed behavior.
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Affiliation(s)
- Wolfram Schultz
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, UK.
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180
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Schultz W. Dopamine signals for reward value and risk: basic and recent data. BEHAVIORAL AND BRAIN FUNCTIONS : BBF 2010; 6:24. [PMID: 20416052 DOI: 10.1186/1744-9081-1186-1124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 04/23/2010] [Indexed: 05/27/2023]
Abstract
BACKGROUND Previous lesion, electrical self-stimulation and drug addiction studies suggest that the midbrain dopamine systems are parts of the reward system of the brain. This review provides an updated overview about the basic signals of dopamine neurons to environmental stimuli. METHODS The described experiments used standard behavioral and neurophysiological methods to record the activity of single dopamine neurons in awake monkeys during specific behavioral tasks. RESULTS Dopamine neurons show phasic activations to external stimuli. The signal reflects reward, physical salience, risk and punishment, in descending order of fractions of responding neurons. Expected reward value is a key decision variable for economic choices. The reward response codes reward value, probability and their summed product, expected value. The neurons code reward value as it differs from prediction, thus fulfilling the basic requirement for a bidirectional prediction error teaching signal postulated by learning theory. This response is scaled in units of standard deviation. By contrast, relatively few dopamine neurons show the phasic activation following punishers and conditioned aversive stimuli, suggesting a lack of relationship of the reward response to general attention and arousal. Large proportions of dopamine neurons are also activated by intense, physically salient stimuli. This response is enhanced when the stimuli are novel; it appears to be distinct from the reward value signal. Dopamine neurons show also unspecific activations to non-rewarding stimuli that are possibly due to generalization by similar stimuli and pseudoconditioning by primary rewards. These activations are shorter than reward responses and are often followed by depression of activity. A separate, slower dopamine signal informs about risk, another important decision variable. The prediction error response occurs only with reward; it is scaled by the risk of predicted reward. CONCLUSIONS Neurophysiological studies reveal phasic dopamine signals that transmit information related predominantly but not exclusively to reward. Although not being entirely homogeneous, the dopamine signal is more restricted and stereotyped than neuronal activity in most other brain structures involved in goal directed behavior.
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Affiliation(s)
- Wolfram Schultz
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, UK.
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181
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Jones JL, Day JJ, Aragona BJ, Wheeler RA, Wightman RM, Carelli RM. Basolateral amygdala modulates terminal dopamine release in the nucleus accumbens and conditioned responding. Biol Psychiatry 2010; 67:737-44. [PMID: 20044074 PMCID: PMC2849914 DOI: 10.1016/j.biopsych.2009.11.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Revised: 11/06/2009] [Accepted: 11/07/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND Dopamine signaling in the nucleus accumbens (NAc) is essential for goal-directed behaviors and primarily arises from burst firing of ventral tegmental area neurons. However, the role of associative neural substrates such as the basolateral amygdala (BLA) in regulating phasic dopamine release in the NAc, particularly during reward seeking, remains unknown. METHODS Male Sprague-Dawley rats learned to discriminate two cues: a discriminative stimulus (DS) that predicted sucrose reinforcement contingent upon a lever press and a nonassociated stimulus (NS) that predicted a second lever never reinforced with sucrose. Following training, a test session was completed in which NAc dopamine was measured using fast-scan cyclic voltammetry in conjunction with inactivation of the ipsilateral BLA (gamma-aminobutyric acid agonists; baclofen/muscimol) to determine the contribution of BLA activity to dopamine release in the NAc core during the task. RESULTS Under vehicle conditions, DS and NS presentation elicited dopamine release within the NAc core. The DS evoked significantly more dopamine than the NS. Inactivation of the BLA selectively attenuated the magnitude of DS-evoked dopamine release, concurrent with an attenuation of DS-evoked conditioned approaches. Other behavioral responses (e.g., lever pressing) and dopamine release concomitant with those events were unaltered by BLA inactivation. Furthermore, neither ventral tegmental area electrically stimulated dopamine release nor the probability of high concentration dopamine release events was altered following BLA inactivation. CONCLUSIONS These results demonstrate that the BLA terminally modulates dopamine signals within the NAc core under specific, behaviorally relevant conditions, illustrating a functional mechanism by which the BLA selectively facilitates responding to motivationally salient environmental stimuli.
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Affiliation(s)
- Joshua L. Jones
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Jeremy J. Day
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Brandon J. Aragona
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Robert A. Wheeler
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - R. Mark Wightman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599,Neuroscience Center University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Regina M. Carelli
- Department of Psychology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599,Neuroscience Center University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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182
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Abstract
Dopamine is a key neuromodulatory transmitter in the brain. It acts through
dopamine receptors to affect changes in neural activity, gene expression, and
behavior. In songbirds, dopamine is released into the striatal song nucleus Area
X, and the levels depend on social contexts of undirected and directed singing.
This differential release is associated with differential expression of
activity-dependent genes, such as egr1 (avian zenk), which in mammalian brain
are modulated by dopamine receptors. Here we cloned from zebra finch brain cDNAs
of all avian dopamine receptors: the D1 (D1A, D1B, D1D) and D2 (D2, D3, D4)
families. Comparative sequence analyses of predicted proteins revealed expected
phylogenetic relationships, in which the D1 family exists as single exon and the
D2 family exists as spliced exon genes. In both zebra finch and chicken, the
D1A, D1B, and D2 receptors were highly expressed in the striatum, the D1D and D3
throughout the pallium and within the mesopallium, respectively, and the D4
mainly in the cerebellum. Furthermore, within the zebra finch, all receptors,
except for D4, showed differential expression in song nuclei relative to the
surrounding regions and developmentally regulated expression that decreased for
most receptors during the sensory acquisition and sensorimotor phases of song
learning. Within Area X, half of the cells expressed both D1A and D2 receptors,
and a higher proportion of the D1A-only-containing neurons expressed egr1 during
undirected but not during directed singing. Our findings are consistent with
hypotheses that dopamine receptors may be involved in song development and
social context-dependent behaviors. J. Comp. Neurol. 518:741–769, 2010.
© 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Lubica Kubikova
- Department of Neurobiology, Howard Hughes Medical Institute, Duke University Medical Center, Durham, North Carolina 27710, USA.
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183
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Peterson DA, Sejnowski TJ, Poizner H. Convergent evidence for abnormal striatal synaptic plasticity in dystonia. Neurobiol Dis 2010; 37:558-73. [PMID: 20005952 PMCID: PMC2846420 DOI: 10.1016/j.nbd.2009.12.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 11/30/2009] [Accepted: 12/03/2009] [Indexed: 11/24/2022] Open
Abstract
Dystonia is a functionally disabling movement disorder characterized by abnormal movements and postures. Although substantial recent progress has been made in identifying genetic factors, the pathophysiology of the disease remains a mystery. A provocative suggestion gaining broader acceptance is that some aspect of neural plasticity may be abnormal. There is also evidence that, at least in some forms of dystonia, sensorimotor "use" may be a contributing factor. Most empirical evidence of abnormal plasticity in dystonia comes from measures of sensorimotor cortical organization and physiology. However, the basal ganglia also play a critical role in sensorimotor function. Furthermore, the basal ganglia are prominently implicated in traditional models of dystonia, are the primary targets of stereotactic neurosurgical interventions, and provide a neural substrate for sensorimotor learning influenced by neuromodulators. Our working hypothesis is that abnormal plasticity in the basal ganglia is a critical link between the etiology and pathophysiology of dystonia. In this review we set up the background for this hypothesis by integrating a large body of disparate indirect evidence that dystonia may involve abnormalities in synaptic plasticity in the striatum. After reviewing evidence implicating the striatum in dystonia, we focus on the influence of two neuromodulatory systems: dopamine and acetylcholine. For both of these neuromodulators, we first describe the evidence for abnormalities in dystonia and then the means by which it may influence striatal synaptic plasticity. Collectively, the evidence suggests that many different forms of dystonia may involve abnormal plasticity in the striatum. An improved understanding of these altered plastic processes would help inform our understanding of the pathophysiology of dystonia, and, given the role of the striatum in sensorimotor learning, provide a principled basis for designing therapies aimed at the dynamic processes linking etiology to pathophysiology of the disease.
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Affiliation(s)
- David A Peterson
- Institute for Neural Computation, University of California at San Diego, San Diego Supercomputer Center-Annex, 0523, Level B-1, South Wing, B108E, La Jolla, CA 92093-0523, USA.
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184
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Kheirbek MA, Beeler JA, Chi W, Ishikawa Y, Zhuang X. A molecular dissociation between cued and contextual appetitive learning. Learn Mem 2010; 17:148-54. [PMID: 20189959 DOI: 10.1101/lm.1687310] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In appetitive Pavlovian learning, animals learn to associate discrete cues or environmental contexts with rewarding outcomes, and these cues and/or contexts can potentiate an ongoing instrumental response for reward. Although anatomical substrates underlying cued and contextual learning have been proposed, it remains unknown whether specific molecular signaling pathways within the striatum underlie one form of learning or the other. Here, we show that while the striatum-enriched isoform of adenylyl cyclase (AC5) is required for cued appetitive Pavlovian learning, it is not required for contextual appetitive learning. Mice lacking AC5 (AC5KO) could not learn an appetitive Pavlovian learning task in which a discrete signal light predicted reward delivery, yet they could form associations between context and either natural or drug reward, which could in turn elicit Pavlovian approach behavior. However, unlike wild-type (WT) mice, AC5KO mice could not use these Pavlovian conditioned stimuli to potentiate ongoing instrumental behavior in a Pavlovian-to-instrumental transfer paradigm. These data suggest that AC5 is specifically required for learning associations between discrete cues and outcomes in which the temporal relationship between conditioned stimulus (CS) and unconditioned stimulus (US) is essential, while alternative signaling mechanisms may underlie the formation of associations between context and reward. In addition, loss of AC5 compromises the ability of both contextual and discrete cues to modulate instrumental behavior.
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Affiliation(s)
- Mazen A Kheirbek
- Committee on Neurobiology, The University of Chicago, Chicago, Illinois 60637, USA.
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185
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Minuzzi L, Cumming P. Agonist binding fraction of dopamine D2/3 receptors in rat brain: a quantitative autoradiographic study. Neurochem Int 2010; 56:747-52. [PMID: 20117160 DOI: 10.1016/j.neuint.2010.01.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 01/22/2010] [Indexed: 02/02/2023]
Abstract
There has arisen considerable interest in the study of dopamine D(2/3) agonist binding sites by positron emission tomography (PET), based on the claim that agonist sites represent a functional subset of the total number of sites labeled by more conventional antagonist ligands. To test the basis of this claim, we used quantitative autoradiography to measure the abundance of binding sites of a dopamine D(2/3) agonist ([(3)H]NPA) and an antagonist ([(3)H]raclopride) in cryosections of rat brain. Saturation binding studies revealed that the B(max) for [(3)H]NPA was nearly identical to that of [(3)H]raclopride in dorsal brain regions, but was 25% less in the ventral striatum and 56% less in the olfactory tubercle. We also tested the displacement of the two ligands by the hallucinogen LSD, which is known to have dopamine agonist properties. Whereas displacement of [(3)H]raclopride by increasing LSD concentrations was monophasic, displacement of [(3)H]NPA was biphasic, suggesting an action of LSD via a subset of dopamine D(2/3) agonist binding sites. Addition of the stable GTP analogue Gpp(NH)p to the medium abolished 90% of the [(3)H]NPA binding, and increased [(3)H]raclopride binding by 10%, with a shift to the right in the LSD competition curve, suggesting retention of endogenous dopamine in washed cryostat sections. Thus [(3)H]NPA and [(3)H]raclopride binding sites have nearly identical abundances in rat dorsal striatum, but are distinct in the ventral striatum, and with respect to their displacement by LSD.
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186
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Lovinger DM. Neurotransmitter roles in synaptic modulation, plasticity and learning in the dorsal striatum. Neuropharmacology 2010; 58:951-61. [PMID: 20096294 DOI: 10.1016/j.neuropharm.2010.01.008] [Citation(s) in RCA: 366] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 01/08/2010] [Accepted: 01/12/2010] [Indexed: 02/08/2023]
Abstract
The dorsal striatum is a large forebrain region involved in action initiation, timing, control, learning and memory. Learning and remembering skilled movement sequences requires the dorsal striatum, and striatal subregions participate in both goal-directed (action-outcome) and habitual (stimulus-response) learning. Modulation of synaptic transmission plays a large part in controlling input to as well as the output from striatal medium spiny projection neurons (MSNs). Synapses in this brain region are subject to short-term modulation, including allosteric alterations in ion channel function and prominent presynaptic inhibition. Two forms of long-term synaptic plasticity have also been observed in striatum, long-term potentiation (LTP) and long-term depression (LTD). LTP at glutamatergic synapses onto MSNs involves activation of NMDA-type glutamate receptors and D1 dopamine or A2A adenosine receptors. Expression of LTP appears to involve postsynaptic mechanisms. LTD at glutamatergic synapses involves retrograde endocannabinoid signaling stimulated by activation of metabotropic glutamate receptors (mGluRs) and D2 dopamine receptors. While postsynaptic mechanisms participate in LTD induction, maintained expression involves presynaptic mechanisms. A similar form of LTD has also been observed at GABAergic synapses onto MSNs. Studies have just begun to examine the roles of synaptic plasticity in striatal-based learning. Findings to date indicate that molecules implicated in induction of plasticity participate in these forms of learning. Neurotransmitter receptors involved in LTP induction are necessary for proper skill and goal-directed instrumental learning. Interestingly, receptors involved in LTP and LTD at glutamatergic synapses onto MSNs of the "indirect pathway" appear to have important roles in habit learning. More work is needed to reveal if and when synaptic plasticity occurs during learning and if so what molecules and cellular processes, both short- and long-term, contribute to this plasticity.
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Affiliation(s)
- David M Lovinger
- Laboratory for Integrative Neuroscience, NIAAA/NIH, 5625 Fishers Lane, Rockville, MD 20852, USA.
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187
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Regulation of Extracellular Dopamine. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/b978-0-12-374767-9.00017-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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188
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Martí M, Fabregat G, Estrany F, Alemán C, Armelin E. Nanostructured conducting polymer for dopamine detection. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm01364a] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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189
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Gerfen CR, Bolam JP. The Neuroanatomical Organization of the Basal Ganglia. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/b978-0-12-374767-9.00001-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
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190
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Abstract
Previous studies have shown that imaging with positron emission tomography (PET) and single photon emission computed tomography (SPECT) radiotracers that are specific for brain dopamine receptors can be used to indirectly image the change in the levels of neurotransmitters within the brain. Most of the studies in addiction have focused on dopamine, since the dopamine neurons that project to the striatum have been shown to play a critical role in mediating addictive behavior. These imaging studies have shown that increased extracellular dopamine produced by psychostimulants can be measured with PET and SPECT. However, there are some technical issues associated with imaging changes in dopamine, and these are reviewed in this chapter. Among these are the loss of sensitivity, the time course of dopamine pulse relative to PET and SPECT imaging, and the question of affinity state of the receptor. In addition, animal studies have shown that most drugs of abuse increase extracellular dopamine in the striatum, yet not all produce a change in neurotransmitter that can be measured. As a result, imaging with a psychostimulant has become the preferred method for imaging presynaptic dopamine transmission, and this method has been used in studies of addiction. The results of these studies suggest that cocaine and alcohol addiction are associated with a loss of dopamine transmission, and a number of studies show that this loss correlates with severity of disease.
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191
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Nucleus accumbens dopamine mediates amphetamine-induced impairment of social bonding in a monogamous rodent species. Proc Natl Acad Sci U S A 2009; 107:1217-22. [PMID: 20080553 DOI: 10.1073/pnas.0911998107] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The prairie vole (Microtus ochrogaster) is a socially monogamous rodent species that forms pair bonds after mating, a behavior in which central dopamine (DA) has been implicated. Here, we used male prairie voles to examine the effects of drug exposure on pair bonding and related neural circuitry. In our first experiment, amphetamine (AMPH) motivated behavior was examined using a conditioned place preference (CPP) paradigm and was shown to be mediated by activation of D1-like DA receptors. Next, we examined the effects of repeated AMPH exposure on pair bonding. Intact and saline pretreated control males displayed mating-induced partner preferences, whereas males pretreated with AMPH at the doses effective to induce CPP failed to show mating-induced partner preferences. Such AMPH treatment also enhanced D1, but not D2, DA receptor expression in the nucleus accumbens (NAcc). Furthermore, pharmacological blockade of D1-like DA receptors in the NAcc rescued mating-induced partner preferences in AMPH-treated males. Together, our data indicate that repeated AMPH exposure may narrow the behavioral repertoire of male prairie voles via a DA receptor-specific mechanism in the NAcc, resulting in the impairment of pair bond formation.
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192
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Humphries MD, Lepora N, Wood R, Gurney K. Capturing dopaminergic modulation and bimodal membrane behaviour of striatal medium spiny neurons in accurate, reduced models. Front Comput Neurosci 2009; 3:26. [PMID: 20011223 PMCID: PMC2791037 DOI: 10.3389/neuro.10.026.2009] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Accepted: 10/24/2009] [Indexed: 11/13/2022] Open
Abstract
Loss of dopamine from the striatum can cause both profound motor deficits, as in Parkinson's disease, and disrupt learning. Yet the effect of dopamine on striatal neurons remains a complex and controversial topic, and is in need of a comprehensive framework. We extend a reduced model of the striatal medium spiny neuron (MSN) to account for dopaminergic modulation of its intrinsic ion channels and synaptic inputs. We tune our D1 and D2 receptor MSN models using data from a recent large-scale compartmental model. The new models capture the input-output relationships for both current injection and spiking input with remarkable accuracy, despite the order of magnitude decrease in system size. They also capture the paired pulse facilitation shown by MSNs. Our dopamine models predict that synaptic effects dominate intrinsic effects for all levels of D1 and D2 receptor activation. We analytically derive a full set of equilibrium points and their stability for the original and dopamine modulated forms of the MSN model. We find that the stability types are not changed by dopamine activation, and our models predict that the MSN is never bistable. Nonetheless, the MSN models can produce a spontaneously bimodal membrane potential similar to that recently observed in vitro following application of NMDA agonists. We demonstrate that this bimodality is created by modelling the agonist effects as slow, irregular and massive jumps in NMDA conductance and, rather than a form of bistability, is due to the voltage-dependent blockade of NMDA receptors. Our models also predict a more pronounced membrane potential bimodality following D1 receptor activation. This work thus establishes reduced yet accurate dopamine-modulated models of MSNs, suitable for use in large-scale models of the striatum. More importantly, these provide a tractable framework for further study of dopamine's effects on computation by individual neurons.
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Affiliation(s)
- Mark D Humphries
- Adaptive Behaviour Research Group, Department of Psychology, University of Sheffield Sheffield, UK
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193
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Humphries MD, Prescott TJ. The ventral basal ganglia, a selection mechanism at the crossroads of space, strategy, and reward. Prog Neurobiol 2009; 90:385-417. [PMID: 19941931 DOI: 10.1016/j.pneurobio.2009.11.003] [Citation(s) in RCA: 243] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 11/12/2009] [Accepted: 11/16/2009] [Indexed: 11/27/2022]
Abstract
The basal ganglia are often conceptualised as three parallel domains that include all the constituent nuclei. The 'ventral domain' appears to be critical for learning flexible behaviours for exploration and foraging, as it is the recipient of converging inputs from amygdala, hippocampal formation and prefrontal cortex, putatively centres for stimulus evaluation, spatial navigation, and planning/contingency, respectively. However, compared to work on the dorsal domains, the rich potential for quantitative theories and models of the ventral domain remains largely untapped, and the purpose of this review is to provide the stimulus for this work. We systematically review the ventral domain's structures and internal organisation, and propose a functional architecture as the basis for computational models. Using a full schematic of the structure of inputs to the ventral striatum (nucleus accumbens core and shell), we argue for the existence of many identifiable processing channels on the basis of unique combinations of afferent inputs. We then identify the potential information represented in these channels by reconciling a broad range of studies from the hippocampal, amygdala and prefrontal cortex literatures with known properties of the ventral striatum from lesion, pharmacological, and electrophysiological studies. Dopamine's key role in learning is reviewed within the three current major computational frameworks; we also show that the shell-based basal ganglia sub-circuits are well placed to generate the phasic burst and dip responses of dopaminergic neurons. We detail dopamine's modulation of ventral basal ganglia's inputs by its actions on pre-synaptic terminals and post-synaptic membranes in the striatum, arguing that the complexity of these effects hint at computational roles for dopamine beyond current ideas. The ventral basal ganglia are revealed as a constellation of multiple functional systems for the learning and selection of flexible behaviours and of behavioural strategies, sharing the common operations of selection-by-disinhibition and of dopaminergic modulation.
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Affiliation(s)
- Mark D Humphries
- Adaptive Behaviour Research Group, Department of Psychology, University of Sheffield, S10 2TN, UK.
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194
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Aragona BJ, Day JJ, Roitman MF, Cleaveland NA, Wightman RM, Carelli RM. Regional specificity in the real-time development of phasic dopamine transmission patterns during acquisition of a cue-cocaine association in rats. Eur J Neurosci 2009; 30:1889-99. [PMID: 19912327 DOI: 10.1111/j.1460-9568.2009.07027.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Drug seeking is significantly regulated by drug-associated cues and associative learning between environmental cues and cocaine reward is mediated by dopamine transmission within the nucleus accumbens (NAc). However, dopamine transmission during early acquisition of a cue-cocaine association has never been assessed because of the technical difficulties associated with resolving cue-evoked and cocaine-evoked dopamine release within the same conditioning trial. Here, we used fast-scan cyclic voltammetry to measure sub-second fluctuations in dopamine concentration within the NAc core and shell during the initial acquisition of a cue-cocaine Pavlovian association. Within the NAc core, cue-evoked dopamine release developed during conditioning. However, within the NAc shell, the predictive cue appeared to cause an unconditioned decrease in dopamine concentration. The pharmacological effects of cocaine also differed between sub-regions, as cocaine increased phasic dopamine release events within the NAc shell but not the core. Thus, real-time measurements not only revealed the initial development of a conditioned neurochemical response but also demonstrated differential phasic dopamine transmission patterns across NAc sub-regions during the acquisition of a cue-cocaine association.
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Affiliation(s)
- Brandon J Aragona
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, USA.
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195
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Abstract
Synaptic transmission mediated by G-protein coupled receptors (GPCR) is not generally thought to be point-to-point. To determine the extent over which dopamine signals in the midbrain, the present study examined the concentration and time course of dopamine that underlies a D(2)-receptor IPSC (D(2)-IPSC) in the ventral tegmental area. Extracellular dopamine was measured electrochemically while simultaneously recording D(2)-IPSCs. The presence of dopamine was brief relative to the IPSC, suggesting that G-protein dependent potassium channel activation determined the IPSC time course. The activation kinetics of D(2) receptor-dependent potassium current was studied using outside-out patch recordings with rapid application of dopamine. Dopamine applied at a minimum concentration of 10 mum for a maximum of 100 ms mimicked the IPSC. Higher concentrations applied for as little as 5 ms did not change the kinetics of the current. The results indicate that both the intrinsic kinetics of G-protein coupled receptor signaling and a rapidly rising high concentration of dopamine determine the time course of the IPSC. Thus, dopamine transmission in the midbrain is more localized then previously proposed.
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196
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Burkhardt JM, Jin X, Costa RM. Dissociable effects of dopamine on neuronal firing rate and synchrony in the dorsal striatum. Front Integr Neurosci 2009; 3:28. [PMID: 19949467 PMCID: PMC2784296 DOI: 10.3389/neuro.07.028.2009] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Accepted: 10/09/2009] [Indexed: 12/21/2022] Open
Abstract
Previous studies showed that dopamine depletion leads to both changes in firing rate and in neuronal synchrony in the basal ganglia. Since dopamine D1 and D2 receptors are preferentially expressed in striatonigral and striatopallidal medium spiny neurons, respectively, we investigated the relative contribution of lack of D1 and/or D2-type receptor activation to the changes in striatal firing rate and synchrony observed after dopamine depletion. Similar to what was observed after dopamine depletion, co-administration of D1 and D2 antagonists to mice chronically implanted with multielectrode arrays in the striatum caused significant changes in firing rate, power of the local field potential (LFP) oscillations, and synchrony measured by the entrainment of neurons to striatal local field potentials. However, although blockade of either D1 or D2 type receptors produced similarly severe akinesia, the effects on neural activity differed. Blockade of D2 receptors affected the firing rate of medium spiny neurons and the power of the LFP oscillations substantially, but it did not affect synchrony to the same extent. In contrast, D1 blockade affected synchrony dramatically, but had less substantial effects on firing rate and LFP power. Furthermore, there was no consistent relation between neurons changing firing rate and changing LFP entrainment after dopamine blockade. Our results suggest that the changes in rate and entrainment to the LFP observed in medium spiny neurons after dopamine depletion are somewhat dissociable, and that lack of D1- or D2-type receptor activation can exert independent yet interactive pathological effects during the progression of Parkinson's disease.
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Affiliation(s)
- John M Burkhardt
- Section on In Vivo Neural Function, Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism of the National Institutes of Health Bethesda, MD, USA
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197
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Ballion B, Frenois F, Zold CL, Chetrit J, Murer MG, Gonon F. D2 receptor stimulation, but not D1, restores striatal equilibrium in a rat model of Parkinsonism. Neurobiol Dis 2009; 35:376-84. [DOI: 10.1016/j.nbd.2009.05.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Revised: 05/26/2009] [Accepted: 05/28/2009] [Indexed: 10/20/2022] Open
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198
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Aragona BJ, Wang Z. Dopamine regulation of social choice in a monogamous rodent species. Front Behav Neurosci 2009; 3:15. [PMID: 19707518 PMCID: PMC2729670 DOI: 10.3389/neuro.08.015.2009] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 07/23/2009] [Indexed: 11/13/2022] Open
Abstract
There is growing appreciation that social decision making in humans is strongly influenced by hedonic and emotional processing. The field of social neuroeconomics has shown that neural systems important for reward are associated with social choice and social preferences in humans. Here, we show that the neurobiology of social preferences in a monogamous rodent species, the prairie vole, is also regulated by neural systems involved in reward and emotional processing. Specifically, we describe how mesolimbic dopamine transmission differentially mediates the formation and maintenance of monogamous pair bonds in this species. Thus, reward processing exerts tremendous regulation over social choice behaviors that serve as the foundation of a rather complex social organization. We conclude that prairie voles are an excellent model system for the neuroscience of social choice and that complex social decision-making can be robustly explained by reward and hedonic processing.
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Affiliation(s)
- Brandon J Aragona
- Department of Psychology and Program in Neuroscience, University of Michigan Ann Arbor, MI 48109, USA.
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199
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Egerton A, Mehta MA, Montgomery AJ, Lappin JM, Howes OD, Reeves SJ, Cunningham VJ, Grasby PM. The dopaminergic basis of human behaviors: A review of molecular imaging studies. Neurosci Biobehav Rev 2009; 33:1109-32. [PMID: 19481108 DOI: 10.1016/j.neubiorev.2009.05.005] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/14/2009] [Accepted: 05/18/2009] [Indexed: 11/16/2022]
Abstract
This systematic review describes human molecular imaging studies which have investigated alterations in extracellular DA levels during performance of behavioral tasks. Whilst heterogeneity in experimental methods limits meta-analysis, we describe the advantages and limitations of different methodological approaches. Interpretation of experimental results may be limited by regional cerebral blood flow (rCBF) changes, head movement and choice of control conditions. We revisit our original study of striatal DA release during video-game playing [Koepp, M.J., Gunn, R.N., Lawrence, A.D., Cunningham, V.J., Dagher, A., Jones, T., Brooks, D.J., Bench, C.J., Grasby, P.M., 1998. Evidence for striatal dopamine release during a video game. Nature 393, 266-268] to illustrate the potentially confounding influences of head movement and alterations in rCBF. Changes in [(11)C]raclopride binding may be detected in extrastriatal as well as striatal brain regions-however we review evidence which suggests that extrastriatal changes may not be clearly interpreted in terms of DA release. Whilst several investigations have detected increases in striatal extracellular DA concentrations during task components such as motor learning and execution, reward-related processes, stress and cognitive performance, the presence of potentially biasing factors should be carefully considered (and, where possible, accounted for) when designing and interpreting future studies.
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Affiliation(s)
- Alice Egerton
- Medical Research Council Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, United Kingdom.
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200
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Abstract
The basal ganglia occupy the core of the forebrain and consist of evolutionarily conserved motor nuclei that form recurrent circuits critical for motivation and motor planning. The striatum is the main input nucleus of the basal ganglia and a key neural substrate for procedural learning and memory. The vast majority of striatal neurons are spiny GABAergic projection neurons, which exhibit slow but temporally precise spiking in vivo. Contributing to this precision are several different types of interneurons that constitute only a small fraction of total neuron number but play a critical role in regulating striatal output. This review examines the cellular physiology and modulation of striatal neurons that give rise to their unique properties and function.
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Affiliation(s)
- Anatol C Kreitzer
- Gladstone Institute of Neurological Disease and Departments of Physiology and Neurology, University of California, San Francisco, California 94158, USA.
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