Dataset Information

Corticostriatal and thalamostriatal synapses have distinctive properties.

ABSTRACT: The two principal excitatory glutamatergic inputs to striatal medium spiny neurons (MSNs) arise from neurons in the cerebral cortex and thalamus. Although there have been many electrophysiological studies of MSN glutamatergic synapses, little is known about how corticostriatal and thalamostriatal synapses differ. Using mouse brain slices that allowed each type of synapse to be selectively activated, electrophysiological approaches were used to characterize their properties in identified striatopallidal and striatonigral MSNs. At corticostriatal synapses, a single afferent volley increased the glutamate released by a subsequent volley, leading to enhanced postsynaptic depolarization with repetitive stimulation. This was true for both striatonigral and striatopallidal MSNs. In contrast, at thalamostriatal synapses, a single afferent volley decreased glutamate released by a subsequent volley, leading to a depressed postsynaptic depolarization with repetitive stimulation. Again, this response pattern was the same in striatonigral and striatopallidal MSNs. These differences in release probability and short-term synaptic plasticity suggest that corticostriatal and thalamostriatal projection systems code information in temporally distinct ways, constraining how they regulate striatal circuitry.

SUBMITTER: Ding J

PROVIDER: S-EPMC3461269 | biostudies-literature | 2008 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Corticostriatal and thalamostriatal synapses have distinctive properties.

Ding Jun J Peterson Jayms D JD Surmeier D James DJ

The Journal of neuroscience : the official journal of the Society for Neuroscience 20080601 25

The two principal excitatory glutamatergic inputs to striatal medium spiny neurons (MSNs) arise from neurons in the cerebral cortex and thalamus. Although there have been many electrophysiological studies of MSN glutamatergic synapses, little is known about how corticostriatal and thalamostriatal synapses differ. Using mouse brain slices that allowed each type of synapse to be selectively activated, electrophysiological approaches were used to characterize their properties in identified striatop ...[more]

PMID: 18562619

Similar Datasets

Project description:Striatal spine loss is a key pathological feature of Parkinson's disease (PD). Knowing that striatal glutamatergic afferents target dendritic spines, these data appear difficult to reconcile with evidence for an increased expression of the vesicular glutamate transporter 1 (vGluT1) in the striatum of PD patients and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys, as well as in some electrophysiological studies showing overactivity of the corticostriatal glutamatergic system in models of parkinsonism. To address the possibility that structural changes in glutamatergic afferents may underlie these discrepancies, we undertook an ultrastructural analysis of vGluT1-positive (i.e., corticostriatal) and vGluT2-positive (i.e., mostly thalamostriatal) axo-spinous glutamatergic synapses using a 3D electron microscopic approach in normal and MPTP-treated monkeys. Three main conclusions can be drawn: 1) spines contacted by vGluT1-containing terminals have larger volume and harbor significantly larger postsynaptic densities (PSDs) than those contacted by vGluT2-immunoreactive boutons; 2) a subset of vGluT2-, but not vGluT1-immunoreactive, terminals display a pattern of multisynaptic connectivity in normal and MPTP-treated monkeys; and 3) VGluT1- and vGluT2-positive axo-spinous synapses undergo ultrastructural changes (larger spine volume, larger PSDs, increased PSD perforations, larger presynaptic terminal) indicative of increased synaptic activity in parkinsonian animals. Furthermore, spines contacted by cortical terminals display an increased volume of their spine apparatus in MPTP-treated monkeys, suggesting an increased protein synthesis at corticostriatal synapses. These findings demonstrate that corticostriatal and thalamostriatal glutamatergic axo-spinous synapses display significantly different ultrastructural features, and that both systems undergo complex morphological changes that could underlie the pathophysiology of corticostriatal and thalamostriatal systems in PD.

Project description:BackgroundThe network pathophysiology underlying the motor symptoms of Parkinson's disease (PD) is poorly understood. In models of late-stage PD, there is significant cell-specific remodeling of corticostriatal, axospinous glutamatergic synapses on principal spiny projection neurons (SPNs). Neurons in the centrolateral nucleus (CLN) of the thalamus that relay cerebellar activity to the striatum also make axospinous synapses on SPNs, but the extent to which they are affected in PD has not been definitively characterized.ObjectiveTo fill this gap, transgenic mice in which CLN neurons express Cre recombinase were used in conjunction with optogenetic and circuit mapping approaches to determine changes in the CLN projection to SPNs in a unilateral 6-hydroxydopamine (6-OHDA) model of late-stage PD.MethodsAdeno-associated virus vectors carrying Cre-dependent opsin expression constructs were stereotaxically injected into the CLN of Grp-KH288 mice in which CLN, but not parafascicular nucleus neurons, expressed Cre recombinase. The properties of this projection to identify direct pathway spiny projection neurons (dSPNs) and indirect pathway spiny projection neurons (iSPNs) were then studied in ex vivo brain slices of the dorsolateral striatum from control and 6-OHDA lesioned mice using anatomic, optogenetic, and electrophysiological approaches.ResultsOptogenetically evoked excitatory synaptic currents in both iSPNs and dSPNs were reduced in lesioned mice; however, the reduction was significantly greater in dSPNs. In iSPNs, the reduction in evoked responses was attributable to synaptic pruning, because synaptic channelrhodopsin assisted circuit mapping (sCRACm) revealed fewer synapses per cell after lesioning. In contrast, sCRACm mapping of CLN inputs to dSPNs failed to detect any change in synapse abundance in lesioned mice. However, the ratio of currents through α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors to those through N-methyl-D-aspartate receptors was significantly reduced in dSPNs. Moreover, the distribution of currents evoked by optical stimulation of individual synapses shifted toward smaller amplitudes by lesioning, suggesting that they had undergone long-term depression.ConclusionsTaken together, our results demonstrate that the CLN projection to the striatum undergoes a pathway-specific remodeling that could contribute to the circuit imbalance thought to drive the hypokinetic features of PD. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Dataset Information

Corticostriatal and thalamostriatal synapses have distinctive properties.

Publications

Corticostriatal and thalamostriatal synapses have distinctive properties.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets