scholarly journals Activation of the basal ganglia and indirect pathway neurons during frontal lobe seizures

Brain ◽  
2021 ◽  
Author(s):  
Anastasia Brodovskaya ◽  
Shinnosuke Shiono ◽  
Jaideep Kapur
Keyword(s):  
Basal Ganglia ◽  
Substantia Nigra ◽  
Frontal Lobe ◽  
Globus Pallidus ◽  
Subthalamic Nucleus ◽  
D2 Receptor ◽  
Field Potential ◽  
Anticonvulsant Effect ◽  
Neuronal Activation ◽  
Indirect Pathway

Abstract There are no detailed descriptions of neuronal circuit active during frontal lobe motor seizures. Using activity reporter mice, local field potential recordings, tissue clearing, viral tracing, and super-resolution microscopy, we found neuronal activation after focal motor to bilateral tonic-clonic seizures in the striatum, globus pallidus externus, subthalamic nucleus, substantia nigra pars reticulata and neurons of the indirect pathway. Seizures preferentially activated dopamine D2 receptor-expressing neurons over D1 in the striatum, which have different projections. Furthermore, the D2 receptor agonist infused into the striatum exerted an anticonvulsant effect. Seizures activate structures via short and long latency loops, and anatomical connections of the seizure focus determine the seizure circuit. These studies, for the first time, show activation of neurons in the striatum, globus pallidus, subthalamic nucleus, and substantia nigra during frontal lobe motor seizures on the cellular level, revealing a complex neuronal activation circuit subject to modulation by the basal ganglia.

Subthalamo-Pallidal Circuit

2017 ◽  
pp. 143-150
Author(s):  
Charles J. Wilson
Keyword(s):  
Basal Ganglia ◽  
Substantia Nigra ◽  
Globus Pallidus ◽  
Subthalamic Nucleus ◽  
Substantia Nigra Pars Reticulata ◽  
Modern Methods

The subthalamo-pallidal system constitutes the second layer of circuitry in the basal ganglia, downstream of the striatum. It consists of four nuclei. Two of them, the external segment of the globus pallidus (GPe) and subthalamic nucleus (STN), make their connections primarily within the basal ganglia. The others, the internal segment of the globus pallidus (GPi) and the substantia nigra pars reticulata (SNr), are the output nuclei of the basal ganglia. Collectively, their axons distribute collaterals to all the targets of the basal ganglia. Rare interneurons have been reported in each of them from studies of Golgi-stained preparations, but they have not so far been confirmed using more modern methods. The circuit as described here is based primarily on studies of the axonal arborizations of neurons stained individually by intracellular or juxtacellular labeling.

Basal Ganglia

2021 ◽  
pp. 141-146
Author(s):  
Farwa Ali ◽  
Eduardo E. Benarroch
Keyword(s):  
Nucleus Accumbens ◽  
Basal Ganglia ◽  
Substantia Nigra ◽  
Motor Learning ◽  
Caudate Nucleus ◽  
Globus Pallidus ◽  
Subthalamic Nucleus ◽  
Motor Program ◽  
Pedunculopontine Nucleus ◽  
Program Selection

The basal ganglia are a group of nuclei that are involved in motor, cognitive, and behavioral circuits and are especially important in motor program selection and motor learning. The key components of the basal ganglia and their circuitry include the striatum (putamen, caudate nucleus, and nucleus accumbens), globus pallidus (GP), subthalamic nucleus (STN), substantia nigra, pedunculopontine nucleus (PPN), and parts of the thalamus and cortex. The basal ganglia have parallel motor, oculomotor, associative, and limbic circuits. This chapter reviews the anatomy and circuitry of the basal ganglia.

Cranial MR findings in Wilson's disease

1997 ◽  
Vol 38 (2) ◽  
pp. 250-258 ◽  
Author(s):  
I. Saatci ◽  
M. Topcu ◽  
F. F. Baltaoglu ◽  
G. Köse ◽  
K. Yalaz ◽  
...  
Keyword(s):  
White Matter ◽  
Basal Ganglia ◽  
Substantia Nigra ◽  
Frontal Lobe ◽  
Globus Pallidus ◽  
Signal Intensity ◽  
Hepatic Dysfunction ◽  
Neurological Involvement ◽  
Hepatic Involvement ◽  
T2 Hyperintensity

Purpose: to define various cranial Mr appearances in Wilson's disease (WD). Material and Methods: MR examinations of 30 patients (9–44 years old) with WD were retrospectively reviewed. Six patients were asymptomatic siblings. Three other patients had isolated hepatic involvement, one with no symptoms. the remaining 21 patients had neurological involvement, 7 of whom had the mixed form of the disease. Nine patients had hepatic dysfunction, the 3 with isolated hepatic involvement and 6 of the 7 with the mixed form. Results: All symptomatic patients (n=23) had abnormal MR examinations. Atrophy was present in the majority of them. the most frequently involved sites were putamen (18/21) and pons (18/21) in patients with neurological abnormality. the putaminal lesions showed a consistent pattern of symmetric, bilateral, concentric-laminar T2 hyperintensity. Putaminal lesions were lacking in only 3 patients with neurological involvement, all of whom were relatively old and had had the disease for a longer duration. Most of the patients with hepatic dysfunction (8/9) had increased T1 signal intensity in the basal ganglia, particularly in the globus pallidus. Pontine involvement always included the dorsal aspect of the pons, however, in some cases the central portion of pons was also affected but ventrolateral longitudinal fibers were spared. Midbrain (16/21), thalamic (10/21) and caudate nucleus lesions (9/21) were also encountered. in a few patients cortical and subcortical white matter lesions were present with a predilection to the frontal lobe, particularly the precentral region. in one patient, a hemorrhagic focus was identified within the white matter lesion. Conclusion: on T2-weighted images, WD is suggested by: atrophy; putaminal lesions with a pattern of symmetric, bilateral, concentric-laminar T2 hyperintensity; and the involvement of the pars compacta of the substantia nigra, periaqueductal gray matter, the pontine tegmentum and the thalamus. the hepatic component of WD may cause increased T1 signal intensity in basal ganglia. in the adult age group, the basal ganglia lesions may be different from those in the pediatric group; the putaminal lesions may not be present; the globus pallidus and substantia nigra may show increased hypointensity on T2-weighted images. Cortical and subcortical lesions may also be present with a predilection to the frontal lobe.

Dopaminergic D2 receptor is a key player in the substantia nigra pars compacta neuronal activation mediated by REM sleep deprivation

2014 ◽  
Vol 76 ◽  
pp. 118-126 ◽  
Author(s):  
Mariana B. Proença ◽  
Patrícia A. Dombrowski ◽  
Claudio Da Cunha ◽  
Luana Fischer ◽  
Anete C. Ferraz ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Sleep Deprivation ◽  
Rem Sleep ◽  
D2 Receptor ◽  
Substantia Nigra Pars Compacta ◽  
Neuronal Activation ◽  
Rem Sleep Deprivation

scholarly journals Endocannabinoids and Dopamine Balance Basal Ganglia Output

2021 ◽  
Vol 15 ◽  
Author(s):  
Lilach Gorodetski ◽  
Yocheved Loewenstern ◽  
Anna Faynveitz ◽  
Izhar Bar-Gad ◽  
Kim T. Blackwell ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Globus Pallidus ◽  
Control Unit ◽  
Vital Role ◽  
Primary Afferents ◽  
Entopeduncular Nucleus ◽  
Indirect Pathway ◽  
Relay Nucleus ◽  
Prevailing View

The entopeduncular nucleus is one of the basal ganglia's output nuclei, thereby controlling basal ganglia information processing. Entopeduncular nucleus neurons integrate GABAergic inputs from the Striatum and the globus pallidus, together with glutamatergic inputs from the subthalamic nucleus. We show that endocannabinoids and dopamine interact to modulate the long-term plasticity of all these primary afferents to the entopeduncular nucleus. Our results suggest that the interplay between dopamine and endocannabinoids determines the balance between direct pathway (striatum) and indirect pathway (globus pallidus) in entopeduncular nucleus output. Furthermore, we demonstrate that, despite the lack of axon collaterals, information is transferred between neighboring neurons in the entopeduncular nucleus via endocannabinoid diffusion. These results transform the prevailing view of the entopeduncular nucleus as a feedforward “relay” nucleus to an intricate control unit, which may play a vital role in the process of action selection.

scholarly journals A Dual Role Hypothesis of the Cortico-Basal-Ganglia Pathways: Opponency and Temporal Difference through Dopamine and Adenosine

2018 ◽  
Author(s):  
Kenji Morita ◽  
Yasuo Kawaguchi
Keyword(s):  
Basal Ganglia ◽  
Activity Patterns ◽  
D2 Receptor ◽  
Medium Spiny Neuron ◽  
Temporal Difference ◽  
Receptor Signaling ◽  
Indirect Pathway ◽  
Wide Range ◽  
Cortical Inputs

The hypothesis that the basal-ganglia direct and indirect pathways represent goodness (or benefit) and badness (or cost) of options, respectively, explains a wide range of phenomena. However, this hypothesis, named the Opponent Actor Learning (OpAL), still has limitations. Structurally, the OpAL model does not incorporate differentiation of the two types of cortical inputs to the basal-ganglia pathways received from intratelencephalic (IT) and pyramidal-tract (PT) neurons. Functionally, the OpAL model does not describe the temporal-difference (TD)-type reward-prediction-error (RPE), nor explains how RPE is calculated in the circuitry connecting to the DA neurons. In fact, there is a different hypothesis on the basal-ganglia pathways and DA, named the Cortico-Striatal-Temporal-Difference (CS-TD) model. The CS-TD model differentiates the IT and PT inputs, describes the TD-type RPE, and explains how TD-RPE is calculated. However, a critical difficulty in this model lies in its assumption that DA induces the same direction of plasticity in both direct and indirect pathways, which apparently contradicts the experimentally observed opposite effects of DA on these pathways. Here, we propose a new hypothesis that integrates the OpAL and CS-TD models. Specifically, we propose that the IT-basal-ganglia pathways represent goodness/badness of current options while the PT-indirect pathway represents the overall value of the previously chosen option, and both of these have influence on the DA neurons, through the basal-ganglia output, so that a variant of TD-RPE is calculated. A key assumption is that opposite directions of plasticity are induced upon phasic activation of DA neurons in the IT-indirect pathway and PT-indirect pathway because of different profiles of IT and PT inputs. Specifically, at PT→indirect-pathway-medium-spiny-neuron (iMSN) synapses, sustained glutamatergic inputs generate rich adenosine, which allosterically prevents DA-D2 receptor signaling and instead favors adenosine-A2A receptor signaling. Then, phasic DA-induced phasic adenosine, which reflects TD-RPE, causes long-term synaptic potentiation. In contrast, at IT→iMSN synapses where adenosine is scarce, phasic DA causes long-term synaptic depression via D2 receptor signaling. This new Opponency & Temporal-Difference (OTD) model provides unique predictions, part of which is potentially in line with recently reported activity patterns of neurons in the globus pallidus externus on the indirect pathway.

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