scholarly journals Striatal Control of Movement: A Role for New Neuronal (Sub-) Populations?

2021 ◽  
Vol 15 ◽  
Author(s):  
Tim Fieblinger

The striatum is a very heterogenous brain area, composed of different domains and compartments, albeit lacking visible anatomical demarcations. Two populations of striatal spiny projection neurons (SPNs) build the so-called direct and indirect pathway of the basal ganglia, whose coordinated activity is essential to control locomotion. Dysfunction of striatal SPNs is part of many movement disorders, such as Parkinson’s disease (PD) and L-DOPA-induced dyskinesia. In this mini review article, I will highlight recent studies utilizing single-cell RNA sequencing to investigate the transcriptional profiles of striatal neurons. These studies discover that SPNs carry a transcriptional signature, indicating both their anatomical location and compartmental identity. Furthermore, the transcriptional profiles reveal the existence of additional distinct neuronal populations and previously unknown SPN sub-populations. In a parallel development, studies in rodent models of PD and L-DOPA-induced dyskinesia (LID) report that direct pathway SPNs do not react uniformly to L-DOPA therapy, and that only a subset of these neurons is underlying the development of abnormal movements. Together, these studies demonstrate a new level of cellular complexity for striatal (dys-) function and locomotor control.

2009 ◽  
Vol 102 (4) ◽  
pp. 2334-2341 ◽  
Author(s):  
Kristen A. Ford ◽  
Stefan Everling

The basal ganglia (BG) play a central role in movement and it has been demonstrated that the discharge rate of neurons in these structures are modulated by the behavioral context of a given task. Here we used the antisaccade task, in which a saccade toward a flashed visual stimulus must be inhibited in favor of a saccade to the opposite location, to investigate the role of the caudate nucleus, a major input structure of the BG, in flexible behavior. In this study, we recorded extracellular neuronal activity while monkeys performed pro- and antisaccade trials. We identified two populations of neurons: those that preferred contralateral saccades (CSNs) and those that preferred ipsilateral saccades (ISNs). CSNs increased their firing rates for prosaccades, but not for antisaccades, and ISNs increased their firing rates for antisaccades, but not for prosaccades. We propose a model in which CSNs project to the direct BG pathway, facilitating saccades, and ISNs project to the indirect pathway, suppressing saccades. This model suggests one possible mechanism by which these neuronal populations could be modulating activity in the superior colliculus.


2021 ◽  
Author(s):  
Vernie Aguda ◽  
Helen Chasiotis ◽  
Indira Riadi ◽  
Tod Rogers Thiele

Striatal neurons within the basal ganglia play a central role in vertebrate action selection; however, their location in larval zebrafish is not well defined. We assayed for conserved striatal markers in the zebrafish subpallium using fluorescent in situ hybridization (FISH) and immunohistochemistry. Whole mount FISH revealed an inhibitory neuronal cluster rostral to the anterior commissure that expresses tac1, the gene that encodes the precursor peptide for substance P. This molecular profile is shared by mammalian striatal direct pathway neurons. A second partially overlapping population of inhibitory neurons was identified that expresses penka, the gene that encodes the precursor peptide for enkephalin. This molecular profile is shared by striatal indirect pathway neurons. Immunostaining for substance P and enkephalin confirmed the presence of these peptides in the subpallium as well as the presence of dopaminergic innervation. The tac1 and penka populations were both found to increase linearly across larval stages. Together, these findings support the existence of a striatal homologue in larval zebrafish that grows to match the development and increasing behavioural complexity of the organism.


Function ◽  
2021 ◽  
Author(s):  
Tanya Sippy ◽  
Corryn Chaimowitz ◽  
Sylvain Crochet ◽  
Carl C H Petersen

Abstract The striatum integrates sensorimotor and motivational signals, likely playing a key role in reward-based learning of goal-directed behavior. However, cell type-specific mechanisms underlying reinforcement learning remain to be precisely determined. Here, we investigated changes in membrane potential dynamics of dorsolateral striatal neurons comparing naïve mice and expert mice trained to lick a reward spout in response to whisker deflection. We recorded from three distinct cell types: i) direct pathway striatonigral neurons, which express type 1 dopamine receptors; ii) indirect pathway striatopallidal neurons, which express type 2 dopamine receptors; and iii) tonically active, putative cholinergic, striatal neurons. Task learning was accompanied by cell type-specific changes in the membrane potential dynamics evoked by the whisker deflection and licking in successfully-performed trials. Both striatonigral and striatopallidal types of striatal projection neurons showed enhanced task-related depolarization across learning. Striatonigral neurons showed a prominent increase in a short latency sensory-evoked depolarization in expert compared to naïve mice. In contrast, the putative cholinergic striatal neurons developed a hyperpolarizing response across learning, driving a pause in their firing. Our results reveal cell type-specific changes in striatal membrane potential dynamics across the learning of a simple goal-directed sensorimotor transformation, helpful for furthering the understanding of the various potential roles of different basal ganglia circuits.


2021 ◽  
Author(s):  
Lele Cui ◽  
Shunhang Tang ◽  
Kai Zhao ◽  
Jingwei Pan ◽  
Zhaoran Zhang ◽  
...  

Action selection during decision-making depends on the basal ganglia circuits that comprise the direct and indirect pathways known to oppositely control movement. However, the mechanism for coordinating these opponent pathways during decision-making remains unclear. We address this by employing deep-brain two-photon imaging and optogenetic manipulations of the direct- and indirect-pathway spiny projection neurons (dSPNs and iSPNs) in the posterior striatum during an auditory decision-making behavior. We show that while dSPNs and iSPNs play opposite causal roles during decision-making, each subtype contains divergent ensembles preferring different choices. The ensembles in dSPNs show stronger contralateral dominance than those in iSPNs manifested by higher-level activation and synchronization. Consistent with this asymmetrical contralateral dominance, optogenetic disinhibition of both pathways promoted contralateral choices. A computational model incorporating the striatal ensemble asymmetry recapitulated the causal behavioral effects. Our results uncover the asymmetry between opponent SPN ensembles as a circuit mechanism for action selection during decision-making.


eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Farid N Garas ◽  
Rahul S Shah ◽  
Eszter Kormann ◽  
Natalie M Doig ◽  
Federica Vinciati ◽  
...  

Corticostriatal afferents can engage parvalbumin-expressing (PV+) interneurons to rapidly curtail the activity of striatal projection neurons (SPNs), thus shaping striatal output. Schemes of basal ganglia circuit dynamics generally consider striatal PV+ interneurons to be homogenous, despite considerable heterogeneity in both form and function. We demonstrate that the selective co-expression of another calcium-binding protein, secretagogin (Scgn), separates PV+ interneurons in rat and primate striatum into two topographically-, physiologically- and structurally-distinct cell populations. In rats, these two interneuron populations differed in their firing rates, patterns and relationships with cortical oscillations in vivo. Moreover, the axons of identified PV+/Scgn+ interneurons preferentially targeted the somata of SPNs of the so-called ‘direct pathway’, whereas PV+/Scgn- interneurons preferentially targeted ‘indirect pathway’ SPNs. These two populations of interneurons could therefore provide a substrate through which either of the striatal output pathways can be rapidly and selectively inhibited to subsequently mediate the expression of behavioral routines.


eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Luis Carrillo-Reid ◽  
Michelle Day ◽  
Zhong Xie ◽  
Alexandria E Melendez ◽  
Jyothisri Kondapalli ◽  
...  

Huntington’s disease (HD) is initially characterized by an inability to suppress unwanted movements, a deficit attributable to impaired synaptic activation of striatal indirect pathway spiny projection neurons (iSPNs). To better understand the mechanisms underlying this deficit, striatal neurons in ex vivo brain slices from mouse genetic models of HD were studied using electrophysiological, optical and biochemical approaches. Distal dendrites of iSPNs from symptomatic HD mice were hypoexcitable, a change that was attributable to increased association of dendritic Kv4 potassium channels with auxiliary KChIP subunits. This association was negatively modulated by TrkB receptor signaling. Dendritic excitability of HD iSPNs was rescued by knocking-down expression of Kv4 channels, by disrupting KChIP binding, by restoring TrkB receptor signaling or by lowering mutant-Htt (mHtt) levels with a zinc finger protein. Collectively, these studies demonstrate that mHtt induces reversible alterations in the dendritic excitability of iSPNs that could contribute to the motor symptoms of HD.


2019 ◽  
Author(s):  
Daniel Rial ◽  
Emma Puighermanal ◽  
Emmanuel Valjent ◽  
Serge Schiffmann ◽  
Alban de Kerchove d’Exaerde

AbstractAs an integrator of molecular pathways, mTOR has been associated with diseases including neurodevelopmental, psychiatric and neurodegenerative disorders as autism, schizophrenia, and Huntington’s disease. An important brain area involved in all these diseases is the striatum. However, the mechanisms behind how mTOR is involved in striatal physiology and its relative role in distinct neuronal populations in these striatal-related diseases still remain to be clarified.Taking advantage of the D1-mTOR KO mice (males), we combined behavioural, biochemical, electrophysiological and morphological analysis aiming to untangle the role of mTOR in direct pathway striatal projection neurons (dMSNs) and how this would impact on striatal physiology.Our results indicate deep behavioural changes in absence of mTOR in dMSNs such as decreased spontaneous locomotion, impaired social interaction and repetitive behaviour. These were accompanied by a Kv1.1-induced increase in the fast phase of afterhyperpolarization and decreased distal spines density that were mechanistically independent of protein synthesis but dependent of RhoA activity.These results identify mTOR RhoA signaling as an important regulator of striatal functions through an intricate mechanism involving RhoA and culminating in Kv1.1 overfunction, which could be targeted to treat striatal-related mTORopathies.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
V. Dumrongprechachan ◽  
R. B. Salisbury ◽  
G. Soto ◽  
M. Kumar ◽  
M. L. MacDonald ◽  
...  

AbstractThe vertebrate brain consists of diverse neuronal types, classified by distinct anatomy and function, along with divergent transcriptomes and proteomes. Defining the cell-type specific neuroproteomes is important for understanding the development and functional organization of neural circuits. This task remains challenging in complex tissue, due to suboptimal protein isolation techniques that often result in loss of cell-type specific information and incomplete capture of subcellular compartments. Here, we develop a genetically targeted proximity labeling approach to identify cell-type specific subcellular proteomes in the mouse brain, confirmed by imaging, electron microscopy, and mass spectrometry. We virally express subcellular-localized APEX2 to map the proteome of direct and indirect pathway spiny projection neurons in the striatum. The workflow provides sufficient depth to uncover changes in the proteome of striatal neurons following chemogenetic activation of Gαq-coupled signaling cascades. This method enables flexible, cell-type specific quantitative profiling of subcellular proteome snapshots in the mouse brain.


2019 ◽  
Author(s):  
Fran van Heusden ◽  
Anežka Macey-Dare ◽  
Rohan N. Krajeski ◽  
Andrew Sharott ◽  
Tommas Jan Ellender

AbstractHeterogeneous populations of neural progenitors in the embryonic lateral ganglionic eminence (LGE) generate all GABAergic spiny projection neurons (SPNs) found in the striatum. Here we investigate how this diversity in neural progenitors relates to diversity of adult striatal neurons and circuits. Using a combination of in utero electroporation to fluorescently pulse-label striatal neural progenitors in the LGE, brain slice electrophysiology, electrical and optogenetic circuit mapping and immunohistochemistry, we characterise a population of neural progenitors enriched for apical intermediate progenitors (aIPs) and a distinct population of other progenitors (OPs) and their neural offspring. We find that neural progenitor origin has subtle but significant effects on the properties of striatal SPNs. Although aIP and OP progenitors can both generate D1-expressing direct pathway as well as D2-expressing indirect pathway SPNs found intermingled in the striatum, the aIP derived SPNs are found in more medial aspects of the striatum, exhibit more complex dendritic arbors with higher spine density and differentially sample cortical input. Moreover, optogenetic circuit mapping of the aIP derived neurons show that they further integrate within striatal circuits and innervate both local D1 and D2 SPNs. These results show that it is possible to fluorescently pulse-label distinct neural progenitor pools within the LGE and provide the first evidence that neural progenitor heterogeneity can contribute to the diversity of striatal SPNs.


2007 ◽  
Vol 98 (4) ◽  
pp. 2311-2323 ◽  
Author(s):  
Osvaldo Ibáñez-Sandoval ◽  
Luis Carrillo-Reid ◽  
Elvira Galarraga ◽  
Dagoberto Tapia ◽  
Ernesto Mendoza ◽  
...  

Projection neurons of the substantia nigra reticulata (SNr) convey basal ganglia (BG) processing to thalamocortical and brain stem circuits responsible for movement. Two models try to explain pathological BG performance during Parkinson disease (PD): the rate model, which posits an overexcitation of SNr neurons due to hyperactivity in the indirect pathway and hypoactivity of the direct pathway, and the oscillatory model, which explains PD as the product of pathological pattern generators disclosed by dopamine reduction. These models are, apparently, incompatible. We tested the predictions of the rate model by increasing the excitatory drive and reducing the inhibition on SNr neurons in vitro. This was done pharmacologically with bath application of glutamate agonist N-methyl-d-aspartate and GABAA receptor blockers, respectively. Both maneuvers induced bursting behavior in SNr neurons. Therefore synaptic changes forecasted by the rate model induce the electrical behavior predicted by the oscillatory model. In addition, we found evidence that CaV3.2 Ca2+ channels are a critical step in generating the bursting firing pattern in SNr neurons. Other ion channels involved are: hyperpolarization-activated cation channels, high-voltage-activated Ca2+ channels, and Ca2+-activated K+ channels. However, although these channels shape the temporal structure of bursting, only CaV3.2 Ca2+ channels are indispensable for the initiation of the bursting pattern.


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