Self-Organization in the Basal Ganglia with Modulation of Reinforcement Signals

2002 ◽  
Vol 14 (4) ◽  
pp. 819-844 ◽  
Author(s):  
Hiroyuki Nakahara ◽  
Shun-ichi Amari ◽  
Okihide Hikosaka
Keyword(s):  
Basal Ganglia ◽  
Neural Activity ◽  
Neural Circuits ◽  
Self Organization ◽  
Projection Neurons ◽  
Short Term ◽  
Striatal Projection Neurons ◽  
Rapid Changes ◽  
Sensory Cortices ◽  
Sensory Responses

Self-organization is one of fundamental brain computations for forming efficient representations of information. Experimental support for this idea has been largely limited to the developmental and reorganizational formation of neural circuits in the sensory cortices. We now propose that self-organization may also play an important role in short-term synaptic changesinreward-drivenvoluntarybehaviors.Ithasrecentlybeenshown that many neurons in the basal ganglia change their sensory responses flexibly in relation to rewards. Our computational model proposes that the rapid changes in striatal projection neurons depend on the subtle balance between the Hebb-type mechanisms of excitation and inhibition, which are modulated by reinforcement signals. Simulations based on the model are shown to produce various types of neural activity similar to those found in experiments.

Muscarinic presynaptic modulation in GABAergic pallidal synapses of the rat

2015 ◽  
Vol 113 (3) ◽  
pp. 796-807 ◽  
Author(s):  
Ricardo Hernández-Martínez ◽  
José J. Aceves ◽  
Pavel E. Rueda-Orozco ◽  
Teresa Hernández-Flores ◽  
Omar Hernández-González ◽  
...  
Keyword(s):  
Receptor Agonist ◽  
Projection Neurons ◽  
Quantal Content ◽  
Short Term ◽  
Paired Pulse ◽  
Short Term Plasticity ◽  
Striatal Projection Neurons ◽  
Muscarinic Cholinergic ◽  
Muscarinic Modulation

The external globus pallidus (GPe) is central for basal ganglia processing. It expresses muscarinic cholinergic receptors and receives cholinergic afferents from the pedunculopontine nuclei (PPN) and other regions. The role of these receptors and afferents is unknown. Muscarinic M1-type receptors are expressed by synapses from striatal projection neurons (SPNs). Because axons from SPNs project to the GPe, one hypothesis is that striatopallidal GABAergic terminals may be modulated by M1 receptors. Alternatively, some M1 receptors may be postsynaptic in some pallidal neurons. Evidence of muscarinic modulation in any of these elements would suggest that cholinergic afferents from the PPN, or other sources, could modulate the function of the GPe. In this study, we show this evidence using striatopallidal slice preparations: after field stimulation in the striatum, the cholinergic muscarinic receptor agonist muscarine significantly reduced the amplitude of inhibitory postsynaptic currents (IPSCs) from synapses that exhibited short-term synaptic facilitation. This inhibition was associated with significant increases in paired-pulse facilitation, and quantal content was proportional to IPSC amplitude. These actions were blocked by atropine, pirenzepine, and mamba toxin-7, suggesting that receptors involved were M1. In addition, we found that some pallidal neurons have functional postsynaptic M1 receptors. Moreover, some evoked IPSCs exhibited short-term depression and a different kind of modulation: they were indirectly modulated by muscarine via the activation of presynaptic cannabinoid CB1 receptors. Thus pallidal synapses presenting distinct forms of short-term plasticity were modulated differently.

Differential cortical activation of the striatal direct and indirect pathway cells: reconciling the anatomical and optogenetic results by using a computational method

2014 ◽  
Vol 112 (1) ◽  
pp. 120-146 ◽  
Author(s):  
Kenji Morita
Keyword(s):  
D2 Receptor ◽  
Computational Method ◽  
Cortical Activation ◽  
Projection Neurons ◽  
Indirect Pathway ◽  
Short Term ◽  
Apparent Contradiction ◽  
Striatal Projection Neurons ◽  
Cortical Inputs ◽  
Stimulation Of

The corticostriatal system is considered to be crucially involved in learning and action selection. Anatomical studies have shown that two types of corticostriatal neurons, intratelencephalic (IT) and pyramidal tract (PT) cells, preferentially project to dopamine D1 or D2 receptor-expressing striatal projection neurons, respectively. In contrast, an optogenetic study has shown that stimulation of IT axons evokes comparable responses in D1 and D2 cells and that stimulation of PT axons evokes larger responses in D1 cells. Since the optogenetic study applied brief stimulation only, however, the overall impacts of repetitive inputs remain unclear. Moreover, the apparent contradiction between the anatomical and optogenetic results remains to be resolved. I addressed these issues by using a computational approach. Specifically, I constructed a model of striatal response to cortical inputs, with parameters regarding short-term synaptic plasticity and anatomical connection strength for each connection type. Under the constraint of the optogenetic results, I then explored the parameters that best explain the previously reported paired-pulse ratio of response in D1 and D2 cells to cortical and intrastriatal stimulations, which presumably recruit different compositions of IT and PT fibers. The results indicate that 1) IT→D1 and PT→D2 connections are anatomically stronger than IT→D2 and PT→D1 connections, respectively, consistent with the previous findings, and that 2) IT→D1 and PT→D2 synapses entail short-term facilitation, whereas IT→D2 and PT→D1 synapses would basically show depression, and thereby 3) repetitive IT or PT inputs have larger overall impacts on D1 or D2 cells, respectively, supporting a recently proposed hypothesis on the roles of corticostriatal circuits in reinforcement learning.

scholarly journals Parallel Movement-suppressing Striatal Output Pathways

2020 ◽  
Author(s):  
Qiaoling Cui ◽  
Xixun Du ◽  
Isaac Y. M. Chang ◽  
Arin Pamukcu ◽  
Varoth Lilascharoen ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Basal Ganglia ◽  
Body Movement ◽  
Disease Model ◽  
Projection Neurons ◽  
Indirect Pathway ◽  
Direct Pathway ◽  
Striatal Projection Neurons ◽  
6 Hydroxydopamine

AbstractThe classic basal ganglia circuit model asserts a complete segregation of the two striatal output pathways. Empirical data argue that, in addition to indirect-pathway striatal projection neurons (iSPNs), direct-pathway striatal projection neurons (dSPNs) innervate the external globus pallidus (GPe). However, the functions of the latter were not known. In this study, we interrogated the organization principles of striatopallidal projections and how they are involved in full-body movement in mice (both males and females). In contrast to the canonical motor-promoting role of dSPNs in the dorsomedial striatum (DMSdSPNs), optogenetic stimulation of dSPNs in the dorsolateral striatum (DLSdSPNs) suppressed locomotion. Circuit analyses revealed that dSPNs selectively target Npas1+ neurons in the GPe. In a chronic 6-hydroxydopamine lesion model of Parkinson’s disease, the dSPN-Npas1+ projection was dramatically strengthened. As DLSdSPN-Npas1+ projection suppresses movement, the enhancement of this projection represents a circuit mechanism for the hypokinetic symptoms of Parkinson’s disease that has not been previously considered.Significance statementIn the classic basal ganglia model, the striatum is described as a divergent structure—it controls motor and adaptive functions through two segregated, opponent output streams. However, the experimental results that show the projection from direct-pathway neurons to the external pallidum have been largely ignored. Here, we showed that this striatopallidal sub-pathway targets a select subset of neurons in the external pallidum and is motor-suppressing. We found that this sub-pathway undergoes plastic changes in a Parkinson’s disease model. In particular, our results suggest that the increase in strength of this sub-pathway contributes to the slowness or reduced movements observed in Parkinson’s disease.

Interaction between cognitive and motor cortico-basal ganglia loops during decision making: a computational study

2013 ◽  
Vol 109 (12) ◽  
pp. 3025-3040 ◽  
Author(s):  
M. Guthrie ◽  
A. Leblois ◽  
A. Garenne ◽  
T. Boraud
Keyword(s):  
Decision Making ◽  
Basal Ganglia ◽  
Computational Study ◽  
Selection Process ◽  
Action Selection ◽  
External Input ◽  
Projection Neurons ◽  
Cognitive Level ◽  
Striatal Projection Neurons ◽  
Previous Modeling Study

In a previous modeling study, Leblois et al. (2006) demonstrated an action selection mechanism in cortico-basal ganglia loops based on competition between the positive feedback, direct pathway through the striatum and the negative feedback, hyperdirect pathway through the subthalamic nucleus. The present study investigates how multiple level action selection could be performed by the basal ganglia. To do this, the model is extended in a manner consistent with known anatomy and electrophysiology in three main areas. First, two-level decision making has been incorporated, with a cognitive level selecting based on cue shape and a motor level selecting based on cue position. We show that the decision made at the cognitive level can be used to bias the decision at the motor level. We then demonstrate that, for accurate transmission of information between decision-making levels, low excitability of striatal projection neurons is necessary, a generally observed electrophysiological finding. Second, instead of providing a biasing signal between cue choices as an external input to the network, we show that the action selection process can be driven by reasonable levels of noise. Finally, we incorporate dopamine modulated learning at corticostriatal synapses. As learning progresses, the action selection becomes based on learned visual cue values and is not interfered with by the noise that was necessary before learning.

scholarly journals Do human recordings reveal drastic modulations in the discharge of striatal projection neurons in Parkinson’s disease?

2020 ◽  
Author(s):  
Dan Valsky ◽  
Zvi Israel ◽  
Thomas Boraud ◽  
Hagai Bergman ◽  
Marc Deffains
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Deep Brain Stimulation ◽  
Basal Ganglia ◽  
Neuronal Activity ◽  
Discharge Rate ◽  
Projection Neurons ◽  
Dopamine Depletion ◽  
Striatal Projection Neurons ◽  
Deep Brain

AbstractDopamine depletion of the striatum plays a key role in the pathophysiology of Parkinson’s disease (PD), but our understanding of the changes in the discharge rate and pattern of the striatal projection neurons (SPNs) remains limited. Here, we recorded multi-unit signals from the striatum of PD (N = 934) and dystonic (N = 718) patients undergoing deep brain stimulation surgeries. Using an innovative automated data-driven approach to classify striatal units, we showed that the SPN discharge rate is inversely proportional to the isolation quality and stationarity of the SPNs. In contrast to earlier studies in both PD patients and the non-human primate model of PD, we found no drastic changes in the spiking activity (discharge rate and pattern) of the well-isolated and stationary SPNs of PD patients compared to either dystonic patients or the normal levels of striatal activity reported in healthy animals. Moreover, cluster analysis using SPN discharge properties did not characterize two well-separated SPN subpopulations. There was therefore no specific SPN subpopulation (D1 or D2 SPNs) strongly affected by the pathological state. Instead, our results suggest that moderate changes in SPN discharge are most likely amplified by basal ganglia downstream structures, thus leading to the clinical (motor and non-motor) symptoms of PD.Significance statementIn Parkinson’s disease (PD), the loss of the midbrain dopaminergic neurons leads to massive striatal dopamine depletion that provokes abnormal activity throughout the basal ganglia. However, the impact of dopamine depletion on neuronal activity in the striatum is still highly debated. We recorded and examined the neuronal activity in striatum of PD and dystonic patients undergoing deep brain stimulation surgeries. We found that striatal activity was not drastically higher in PD patients compared to either dystonic patients or the normal levels of striatal activity reported in animal studies. In PD, moderate changes in striatal basal activity are therefore most likely amplified by basal ganglia downstream structures.

scholarly journals Opposing regulation of short-term memory by basal ganglia direct and indirect pathways that are coactive during behavior

2021 ◽  
Author(s):  
Yingjun Tang ◽  
Hongjiang Yang ◽  
Xia Chen ◽  
Zhouzhou Zhang ◽  
Xiao Yao ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Short Term Memory ◽  
Quantitative Difference ◽  
Projection Neurons ◽  
Decision Variable ◽  
Similar Response ◽  
Short Term ◽  
Population Activity ◽  
Term Memory ◽  
Stimulation Of

The basal ganglia direct and indirect pathways are viewed to mediate opposing functions in movement. However, this classic model is challenged by recent findings that both pathways are coactive during behavior. We examined the roles of direct (dSPNs) and indirect (iSPNs) pathway spiny projection neurons in a decision-making task with a short-term memory (STM) component. Optogenetic stimulation of cortical-input-defined dSPNs and iSPNs during STM oppositely biased upcoming licking choice, without affecting licking execution. Optogenetically identified dSPNs and iSPNs showed similar response patterns, although with quantitative difference in spatiotemporal organization. To understand how coactive dSPNs and iSPNs play opposing roles, we recorded population activity in frontal cortex and the basal ganglia output nucleus SNr. Stimulation of dSPNs and iSPNs bidirectionally regulated cortical decision variable through the differential modulation of SNr ramping activity. These results reconcile different views by demonstrating that coactive dSPNs and iSPNs precisely shape cortical activity in a push-pull balance.

Huntingtin Localization In Rat Cortex And Striatum

1999 ◽  
Vol 5 (S2) ◽  
pp. 1298-1299
Author(s):  
William L'Amoreaux ◽  
Sandra Nevins
Keyword(s):  
Basal Ganglia ◽  
Motor Function ◽  
Sodium Periodate ◽  
Female Rats ◽  
Projection Neurons ◽  
Human Tissues ◽  
Rat Cortex ◽  
Striatal Projection Neurons ◽  
Intracellular Vesicles ◽  
The Brain

Huntington’s Disease (HD) is a progressive neurodegenerative disease that is characterized by loss 19 of motor function and a decline in cognitive functions. HD is characterized morphologically by loss of neurons in the basal ganglia. During the progression of HD, striatal projection neurons die but cholinergic and somatostatin-containing intemeurons survive. The mutated gene for HD has been described and the protein transcribed by the disease (huntingtin or HT) described. Within the striatum, there is a lack of correlation between presence of HT and neuronal vulnerability. HT has been shown to be associated with intracellular vesicles in human tissues.Female rats were transcardially perfused with 4% paraformaldehyde, 0.1 M lysine, 10 mM sodium periodate (PLP) in 0.1 M phosphate buffer. Following fixation, the brain was removed and the cortex and striatum removed from the brain as 5 mm3 pieces and transferred to fresh PLP containing 0.25% glutaraldehyde.

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