Abstract
Movement suppression in Parkinson's disease (PD) is thought to arise from increased efficacy of the indirect pathway basal ganglia circuit, relative to the direct pathway. However, the underlying pathophysiological mechanisms remain elusive. To examine whether changes in the strength of synaptic inputs to these circuits contribute to this imbalance, we obtained paired whole-cell recordings from striatal direct- and indirect-pathway medium spiny neurons (dMSNs and iMSNs) and optically stimulated inputs from sensorimotor cortex or intralaminar thalamus in brain slices from control and dopamine-depleted mice. We found that dopamine depletion selectively decreased synaptic strength at thalamic inputs to dMSNs, suggesting that thalamus drives asymmetric activation of basal ganglia circuitry underlying parkinsonian motor impairments. Consistent with this hypothesis, in vivo chemogenetic and optogenetic inhibition of thalamostriatal terminals reversed motor deficits in dopamine-depleted mice. These results implicate thalamostriatal projections in the pathophysiology of PD and support interventions targeting thalamus as a potential therapeutic strategy.
Copyright © 2016 Elsevier Inc. All rights reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adrenergic Agents / toxicity
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Animals
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Corpus Striatum / pathology*
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Disease Models, Animal
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Excitatory Amino Acid Agonists / pharmacology
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Excitatory Postsynaptic Potentials / drug effects
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Excitatory Postsynaptic Potentials / genetics
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Exploratory Behavior
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Functional Laterality
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Homeodomain Proteins / genetics
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Homeodomain Proteins / metabolism
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Medial Forebrain Bundle / injuries
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Mice
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N-Methylaspartate / pharmacology
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Neural Pathways / physiology*
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Oxidopamine / toxicity
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Parkinsonian Disorders / chemically induced
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Parkinsonian Disorders / pathology*
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Synapses / physiology*
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Thalamus / pathology*
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Tyrosine 3-Monooxygenase / metabolism
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Vesicular Glutamate Transport Protein 2 / genetics
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Vesicular Glutamate Transport Protein 2 / metabolism
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alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology
Substances
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Adrenergic Agents
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Excitatory Amino Acid Agonists
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Homeodomain Proteins
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Slc17a6 protein, mouse
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Transcription Factors
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Vesicular Glutamate Transport Protein 2
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empty spiracles homeobox proteins
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N-Methylaspartate
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alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
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Oxidopamine
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Tyrosine 3-Monooxygenase