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  1. Article ; Online: Dopamine across timescales and cell types: Relevance for phenotypes in Parkinson's disease progression.

    Seiler, Jillian L / Zhuang, Xiaowen / Nelson, Alexandra B / Lerner, Talia N

    Experimental neurology

    2024  Volume 374, Page(s) 114693

    Abstract: Dopamine neurons in the substantia nigra pars compacta (SNc) synthesize and release dopamine, a critical neurotransmitter for movement and learning. SNc dopamine neurons degenerate in Parkinson's Disease (PD), causing a host of motor and non-motor ... ...

    Abstract Dopamine neurons in the substantia nigra pars compacta (SNc) synthesize and release dopamine, a critical neurotransmitter for movement and learning. SNc dopamine neurons degenerate in Parkinson's Disease (PD), causing a host of motor and non-motor symptoms. Here, we review recent conceptual advances in our basic understanding of the dopamine system - including our rapidly advancing knowledge of dopamine neuron heterogeneity - with special attention to their importance for understanding PD. In PD patients, dopamine neuron degeneration progresses from lateral SNc to medial SNc, suggesting clinically relevant heterogeneity in dopamine neurons. With technical advances in dopamine system interrogation, we can understand the relevance of this heterogeneity for PD progression and harness it to develop new treatments.
    MeSH term(s) Humans ; Dopamine ; Parkinson Disease/genetics ; Substantia Nigra ; Dopaminergic Neurons ; Phenotype ; Disease Progression
    Chemical Substances Dopamine (VTD58H1Z2X)
    Language English
    Publishing date 2024-01-17
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 207148-4
    ISSN 1090-2430 ; 0014-4886
    ISSN (online) 1090-2430
    ISSN 0014-4886
    DOI 10.1016/j.expneurol.2024.114693
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  2. Article ; Online: Multiple stimulation parameters influence efficacy of deep brain stimulation in parkinsonian mice.

    Schor, Jonathan S / Nelson, Alexandra B

    The Journal of clinical investigation

    2019  Volume 129, Issue 9, Page(s) 3833–3838

    Abstract: Deep brain stimulation (DBS) is used to treat multiple neuropsychiatric disorders, including Parkinson's Disease (PD). Despite widespread clinical use, its therapeutic mechanisms are unknown. Here, we developed a mouse model of subthalamic nucleus (STN) ... ...

    Abstract Deep brain stimulation (DBS) is used to treat multiple neuropsychiatric disorders, including Parkinson's Disease (PD). Despite widespread clinical use, its therapeutic mechanisms are unknown. Here, we developed a mouse model of subthalamic nucleus (STN) DBS for PD, to permit investigation using cell type-specific tools available in mice. We found that electrical STN DBS relieved bradykinesia, as measured by movement velocity. In addition, our model recapitulated several hallmarks of human STN DBS, including rapid onset and offset, frequency dependence, dyskinesia at higher stimulation intensity, and associations between electrode location, therapeutic benefit, and side effects. We used this model to assess whether high frequency stimulation is necessary for effective STN DBS, or if low frequency stimulation can be effective when paired with compensatory adjustments in other parameters. We found that low frequency stimulation, paired with greater pulse width and amplitude, relieved bradykinesia. Moreover, a composite metric incorporating pulse width, amplitude, and frequency predicted therapeutic efficacy better than frequency alone. We found a similar relationship between this composite metric and movement speed in a retrospective analysis of human data, suggesting correlations observed in the mouse model may extend to human patients. Together, these data establish a mouse model for elucidating mechanisms of DBS.
    MeSH term(s) Animals ; Behavior, Animal ; Deep Brain Stimulation/methods ; Disease Models, Animal ; Electrodes ; Humans ; Hypokinesia/metabolism ; Hypokinesia/therapy ; Mice ; Mice, Inbred C57BL ; Oxidopamine ; Parkinson Disease/physiopathology ; Parkinson Disease/therapy ; Retrospective Studies ; Subthalamic Nucleus/physiology
    Chemical Substances Oxidopamine (8HW4YBZ748)
    Language English
    Publishing date 2019-06-13
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 3067-3
    ISSN 1558-8238 ; 0021-9738
    ISSN (online) 1558-8238
    ISSN 0021-9738
    DOI 10.1172/JCI122390
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  3. Article ; Online: Directly to the Point: Dopamine Persistently Enhances Excitability of Direct Pathway Striatal Neurons.

    McGregor, Matthew M / Nelson, Alexandra B

    Neuron

    2020  Volume 106, Issue 2, Page(s) 201–203

    Abstract: In this issue of Neuron, Lahiri and Bevan (2020) investigate the effects of dopamine release on striatal projection neurons. Using perforated patch recordings and optogenetics, they show that dopamine release persistently enhances the intrinsic ... ...

    Abstract In this issue of Neuron, Lahiri and Bevan (2020) investigate the effects of dopamine release on striatal projection neurons. Using perforated patch recordings and optogenetics, they show that dopamine release persistently enhances the intrinsic excitability of direct pathway striatal neurons.
    MeSH term(s) Corpus Striatum ; Dopamine ; Neurons ; Receptors, Dopamine D1 ; Receptors, Dopamine D2
    Chemical Substances Receptors, Dopamine D1 ; Receptors, Dopamine D2 ; Dopamine (VTD58H1Z2X)
    Language English
    Publishing date 2020-05-12
    Publishing country United States
    Document type Journal Article ; Comment
    ZDB-ID 808167-0
    ISSN 1097-4199 ; 0896-6273
    ISSN (online) 1097-4199
    ISSN 0896-6273
    DOI 10.1016/j.neuron.2020.04.005
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  4. Article ; Online: Striatal Indirect Pathway Dysfunction Underlies Motor Deficits in a Mouse Model of Paroxysmal Dyskinesia.

    Nelson, Alexandra B / Girasole, Allison E / Lee, Hsien-Yang / Ptáček, Louis J / Kreitzer, Anatol C

    The Journal of neuroscience : the official journal of the Society for Neuroscience

    2022  Volume 42, Issue 13, Page(s) 2835–2848

    Abstract: Abnormal involuntary movements, or dyskinesias, are seen in many neurologic diseases, including disorders where the brain appears grossly normal. This observation suggests that alterations in neural activity or connectivity may underlie dyskinesias. One ... ...

    Abstract Abnormal involuntary movements, or dyskinesias, are seen in many neurologic diseases, including disorders where the brain appears grossly normal. This observation suggests that alterations in neural activity or connectivity may underlie dyskinesias. One influential model proposes that involuntary movements are driven by an imbalance in the activity of striatal direct and indirect pathway neurons (dMSNs and iMSNs, respectively). Indeed, in some animal models, there is evidence that dMSN hyperactivity contributes to dyskinesia. Given the many diseases associated with dyskinesia, it is unclear whether these findings generalize to all forms. Here, we used male and female mice in a mouse model of paroxysmal nonkinesigenic dyskinesia (PNKD) to assess whether involuntary movements are related to aberrant activity in the striatal direct and indirect pathways. In this model, as in the human disorder PNKD, animals experience dyskinetic attacks in response to caffeine or alcohol. Using optically identified striatal single-unit recordings in freely moving PNKD mice, we found a loss of iMSN firing during dyskinesia bouts. Further, chemogenetic inhibition of iMSNs triggered dyskinetic episodes in PNKD mice. Finally, we found that these decreases in iMSN firing are likely because of aberrant endocannabinoid-mediated suppression of glutamatergic inputs. These data show that striatal iMSN dysfunction contributes to the etiology of dyskinesia in PNKD, and suggest that indirect pathway hypoactivity may be a key mechanism for the generation of involuntary movements in other disorders.
    MeSH term(s) Animals ; Chorea/chemically induced ; Corpus Striatum ; Disease Models, Animal ; Dyskinesias/etiology ; Female ; Levodopa/adverse effects ; Male ; Mice ; Neurons
    Chemical Substances Levodopa (46627O600J)
    Language English
    Publishing date 2022-02-14
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 604637-x
    ISSN 1529-2401 ; 0270-6474
    ISSN (online) 1529-2401
    ISSN 0270-6474
    DOI 10.1523/JNEUROSCI.1614-20.2022
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Circuit Mechanisms of Parkinson's Disease.

    McGregor, Matthew M / Nelson, Alexandra B

    Neuron

    2019  Volume 101, Issue 6, Page(s) 1042–1056

    Abstract: Parkinson's disease (PD) is a complex, multi-system neurodegenerative disorder. The second most common neurodegenerative disorder after Alzheimer's disease, it affects approximately 1% of adults over age 60. Diagnosis follows the development of one or ... ...

    Abstract Parkinson's disease (PD) is a complex, multi-system neurodegenerative disorder. The second most common neurodegenerative disorder after Alzheimer's disease, it affects approximately 1% of adults over age 60. Diagnosis follows the development of one or more of the core motor features of the disease, including tremor, slowing of movement (bradykinesia), and rigidity. However, there are numerous other motor and nonmotor disease manifestations. Many PD symptoms result directly from neurodegeneration; others are driven by aberrant activity patterns in surviving neurons. This latter phenomenon, PD circuit dysfunction, is an area of intense study, as it likely underlies our ability to treat many disease symptoms in the face of (currently) irreversible neurodegeneration. This Review will discuss key clinical features of PD and their basis in neural circuit dysfunction. We will first review important disease symptoms and some of the responsible neuropathology. We will then describe the basal ganglia-thalamocortical circuit, the major locus of PD-related circuit dysfunction, and some of the models that have influenced its study. We will review PD-related changes in network activity, subdividing findings into those that touch on the rate, rhythm, or synchronization of neurons. Finally, we suggest some critical remaining questions for the field and areas for new developments.
    MeSH term(s) Basal Ganglia/physiopathology ; Brain/physiopathology ; Cerebral Cortex/physiopathology ; Humans ; Neural Pathways/physiopathology ; Parkinson Disease/physiopathology ; Thalamus/physiopathology
    Language English
    Publishing date 2019-03-21
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 808167-0
    ISSN 1097-4199 ; 0896-6273
    ISSN (online) 1097-4199
    ISSN 0896-6273
    DOI 10.1016/j.neuron.2019.03.004
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  6. Article ; Online: Altered Iron and Microstructure in Huntington's Disease Subcortical Nuclei: Insight From 7T MRI.

    Yao, Jingwen / Morrison, Melanie A / Jakary, Angela / Avadiappan, Sivakami / Rowley, Paul / Glueck, Julia / Driscoll, Theresa / Geschwind, Michael D / Nelson, Alexandra B / Possin, Kathrine L / Xu, Duan / Hess, Christopher P / Lupo, Janine M

    Journal of magnetic resonance imaging : JMRI

    2024  

    Abstract: Background: Pathophysiological changes of Huntington's disease (HD) can precede symptom onset by decades. Robust imaging biomarkers are needed to monitor HD progression, especially before the clinical onset.: Purpose: To investigate iron ... ...

    Abstract Background: Pathophysiological changes of Huntington's disease (HD) can precede symptom onset by decades. Robust imaging biomarkers are needed to monitor HD progression, especially before the clinical onset.
    Purpose: To investigate iron dysregulation and microstructure alterations in subcortical regions as HD imaging biomarkers, and to associate such alterations with motor and cognitive impairments.
    Study type: Prospective.
    Population: Fourteen individuals with premanifest HD (38.0 ± 11.0 years, 9 females; far-from-onset N = 6, near-onset N = 8), 21 manifest HD patients (49.1 ± 12.1 years, 11 females), and 33 age-matched healthy controls (43.9 ± 12.2 years, 17 females).
    Field strength/sequence: 7 T, T
    Assessment: Volume, susceptibility, fractional anisotropy (FA), and mean diffusivity (MD) within subcortical brain structures were compared across groups, used to establish HD classification models, and correlated to clinical measures and cognitive assessments.
    Statistical tests: Generalized linear model, multivariate logistic regression, receiver operating characteristics with the area under the curve (AUC), and likelihood ratio test comparing a volumetric model to one that also includes susceptibility and diffusion metrics, Wilcoxon paired signed-rank test, and Pearson's correlation. A P-value <0.05 after Benjamini-Hochberg correction was considered statistically significant.
    Results: Significantly higher striatal susceptibility and FA were found in premanifest and manifest HD preceding atrophy, even in far-from-onset premanifest HD compared to controls (putamen susceptibility: 0.027 ± 0.022 vs. 0.018 ± 0.013 ppm; FA: 0.358 ± 0.048 vs. 0.313 ± 0.039). The model with additional susceptibility, FA, and MD features showed higher AUC compared to volume features alone when differentiating premanifest HD from HC (0.83 vs. 0.66), and manifest from premanifest HD (0.94 vs. 0.83). Higher striatal susceptibility significantly correlated with cognitive deterioration in HD (executive function: r = -0.600; socioemotional function: r = -0.486).
    Data conclusion: 7 T MRI revealed iron dysregulation and microstructure alterations with HD progression, which could precede volume loss, provide added value to HD differentiation, and might be associated with cognitive changes.
    Evidence level: 2 TECHNICAL EFFICACY: Stage 2.
    Language English
    Publishing date 2024-01-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1146614-5
    ISSN 1522-2586 ; 1053-1807
    ISSN (online) 1522-2586
    ISSN 1053-1807
    DOI 10.1002/jmri.29195
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  7. Article ; Online: Frontostriatal Projections Regulate Innate Avoidance Behavior.

    Loewke, Adrienne C / Minerva, Adelaide R / Nelson, Alexandra B / Kreitzer, Anatol C / Gunaydin, Lisa A

    The Journal of neuroscience : the official journal of the Society for Neuroscience

    2021  Volume 41, Issue 25, Page(s) 5487–5501

    Abstract: The dorsomedial prefrontal cortex (dmPFC) has been linked to avoidance and decision-making under conflict, key neural computations altered in anxiety disorders. However, the heterogeneity of prefrontal projections has obscured identification of specific ... ...

    Abstract The dorsomedial prefrontal cortex (dmPFC) has been linked to avoidance and decision-making under conflict, key neural computations altered in anxiety disorders. However, the heterogeneity of prefrontal projections has obscured identification of specific top-down projections involved. While the dmPFC-amygdala circuit has long been implicated in controlling reflexive fear responses, recent work suggests that dmPFC-dorsomedial striatum (DMS) projections may be more important for regulating avoidance. Using fiber photometry recordings in both male and female mice during the elevated zero maze task, we show heightened neural activity in frontostriatal but not frontoamygdalar projection neurons during exploration of the anxiogenic open arms. Additionally, using optogenetics, we demonstrate that this frontostriatal projection preferentially excites postsynaptic D
    MeSH term(s) Animals ; Avoidance Learning/physiology ; Behavior, Animal/physiology ; Corpus Striatum/physiology ; Female ; Instinct ; Male ; Mice ; Mice, Inbred C57BL ; Neural Pathways/physiology ; Prefrontal Cortex/physiology
    Language English
    Publishing date 2021-05-17
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 604637-x
    ISSN 1529-2401 ; 0270-6474
    ISSN (online) 1529-2401
    ISSN 0270-6474
    DOI 10.1523/JNEUROSCI.2581-20.2021
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  8. Article ; Online: Aberrant Striatal Activity in Parkinsonism and Levodopa-Induced Dyskinesia.

    Ryan, Michael B / Bair-Marshall, Chloe / Nelson, Alexandra B

    Cell reports

    2018  Volume 23, Issue 12, Page(s) 3438–3446.e5

    Abstract: Action selection relies on the coordinated activity of striatal direct and indirect pathway medium spiny neurons (dMSNs and iMSNs, respectively). Loss of dopamine in Parkinson's disease is thought to disrupt this balance. While dopamine replacement with ... ...

    Abstract Action selection relies on the coordinated activity of striatal direct and indirect pathway medium spiny neurons (dMSNs and iMSNs, respectively). Loss of dopamine in Parkinson's disease is thought to disrupt this balance. While dopamine replacement with levodopa may restore normal function, the development of involuntary movements (levodopa-induced dyskinesia [LID]) limits therapy. How chronic dopamine loss and replacement with levodopa modulate the firing of identified MSNs in behaving animals is unknown. Using optogenetically labeled striatal single-unit recordings, we assess circuit dysfunction in parkinsonism and LID. Counter to current models, we found that following dopamine depletion, iMSN firing was elevated only during periods of immobility, while dMSN firing was dramatically and persistently reduced. Most notably, we identified a subpopulation of dMSNs with abnormally high levodopa-evoked firing rates, which correlated specifically with dyskinesia. These findings provide key insights into the circuit mechanisms underlying parkinsonism and LID, with implications for developing targeted therapies.
    MeSH term(s) Action Potentials ; Animals ; Behavior, Animal ; Corpus Striatum/pathology ; Corpus Striatum/physiopathology ; Dopamine/metabolism ; Dopamine Agonists/pharmacology ; Dyskinesia, Drug-Induced/pathology ; Dyskinesia, Drug-Induced/physiopathology ; Levodopa/adverse effects ; Mice, Inbred C57BL ; Mice, Transgenic ; Motor Activity/drug effects ; Neurons/pathology ; Optogenetics ; Parkinsonian Disorders/pathology ; Parkinsonian Disorders/physiopathology ; Receptors, Dopamine/metabolism
    Chemical Substances Dopamine Agonists ; Receptors, Dopamine ; Levodopa (46627O600J) ; Dopamine (VTD58H1Z2X)
    Language English
    Publishing date 2018-08-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2649101-1
    ISSN 2211-1247 ; 2211-1247
    ISSN (online) 2211-1247
    ISSN 2211-1247
    DOI 10.1016/j.celrep.2018.05.059
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  9. Article ; Online: Bridging the Gap: Muscarinic M4 Receptors Promote Striatal Plasticity in Health and Disease.

    Girasole, Allison E / Nelson, Alexandra B

    Neuron

    2015  Volume 88, Issue 4, Page(s) 621–623

    Abstract: In this issue of Neuron, Shen et al. (2015) demonstrate that the M4 muscarinic receptor regulates striatal plasticity. The authors use an M4-positive allosteric modulator, which facilitates long-term depression in direct pathway neurons and reverses ... ...

    Abstract In this issue of Neuron, Shen et al. (2015) demonstrate that the M4 muscarinic receptor regulates striatal plasticity. The authors use an M4-positive allosteric modulator, which facilitates long-term depression in direct pathway neurons and reverses aberrant plasticity in levodopa-induced dyskinesia.
    MeSH term(s) Animals ; Dopamine Agents/toxicity ; Dyskinesia, Drug-Induced/metabolism ; Levodopa/toxicity ; Neostriatum/drug effects ; Neuronal Plasticity/drug effects ; Parkinsonian Disorders/drug therapy ; RGS Proteins/metabolism ; Receptor, Muscarinic M4/metabolism
    Chemical Substances Dopamine Agents ; RGS Proteins ; Receptor, Muscarinic M4 ; Levodopa (46627O600J)
    Language English
    Publishing date 2015-11-18
    Publishing country United States
    Document type Comment ; Journal Article
    ZDB-ID 808167-0
    ISSN 1097-4199 ; 0896-6273
    ISSN (online) 1097-4199
    ISSN 0896-6273
    DOI 10.1016/j.neuron.2015.11.007
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  10. Article ; Online: Probing striatal microcircuitry to understand the functional role of cholinergic interneurons.

    Girasole, Allison E / Nelson, Alexandra B

    Movement disorders : official journal of the Movement Disorder Society

    2015  Volume 30, Issue 10, Page(s) 1306–1318

    MeSH term(s) Animals ; Cholinergic Neurons/physiology ; Humans ; Interneurons/physiology ; Neostriatum/metabolism ; Neostriatum/physiology ; Neostriatum/physiopathology ; Signal Transduction/physiology
    Language English
    Publishing date 2015-09
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S. ; Review
    ZDB-ID 607633-6
    ISSN 1531-8257 ; 0885-3185
    ISSN (online) 1531-8257
    ISSN 0885-3185
    DOI 10.1002/mds.26340
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