scholarly journals Firing properties and functional connectivity of substantia nigra pars compacta neurones recorded with a multi-electrode arrayin vitro

2010 ◽  
Vol 588 (10) ◽  
pp. 1719-1735 ◽  
Author(s):  
Nicola Berretta ◽  
Giorgio Bernardi ◽  
Nicola B. Mercuri
Keyword(s):  
Functional Connectivity ◽  
Substantia Nigra ◽  
Substantia Nigra Pars Compacta ◽  
Firing Properties

scholarly journals Molecular and functional differences in voltage-activated sodium currents between GABA projection neurons and dopamine neurons in the substantia nigra

2011 ◽  
Vol 106 (6) ◽  
pp. 3019-3034 ◽  
Author(s):  
Shengyuan Ding ◽  
Wei Wei ◽  
Fu-Ming Zhou
Keyword(s):  
Substantia Nigra ◽  
Low Frequency ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Pcr Analysis ◽  
Projection Neurons ◽  
Na Current ◽  
Gaba Neurons ◽  
Voltage Dependent ◽  
Firing Properties

GABA projection neurons (GABA neurons) in the substantia nigra pars reticulata (SNr) and dopamine projection neurons (DA neurons) in substantia nigra pars compacta (SNc) have strikingly different firing properties. SNc DA neurons fire low-frequency, long-duration spikes, whereas SNr GABA neurons fire high-frequency, short-duration spikes. Since voltage-activated sodium (NaV) channels are critical to spike generation, the different firing properties raise the possibility that, compared with DA neurons, NaV channels in SNr GABA neurons have higher density, faster kinetics, and less cumulative inactivation. Our quantitative RT-PCR analysis on immunohistochemically identified nigral neurons indicated that mRNAs for pore-forming NaV1.1 and NaV1.6 subunits and regulatory NaVβ1 and Navβ4 subunits are more abundant in SNr GABA neurons than SNc DA neurons. These α-subunits and β-subunits are key subunits for forming NaV channels conducting the transient NaV current ( INaT), persistent Na current ( INaP), and resurgent Na current ( INaR). Nucleated patch-clamp recordings showed that INaT had a higher density, a steeper voltage-dependent activation, and a faster deactivation in SNr GABA neurons than in SNc DA neurons. INaT also recovered more quickly from inactivation and had less cumulative inactivation in SNr GABA neurons than in SNc DA neurons. Furthermore, compared with nigral DA neurons, SNr GABA neurons had a larger INaR and INaP. Blockade of INaP induced a larger hyperpolarization in SNr GABA neurons than in SNc DA neurons. Taken together, these results indicate that NaV channels expressed in fast-spiking SNr GABA neurons and slow-spiking SNc DA neurons are tailored to support their different spiking capabilities.

scholarly journals Dendritic Architecture Predicts in vivo Firing Pattern in Mouse Ventral Tegmental Area and Substantia Nigra Dopaminergic Neurons

2021 ◽  
Vol 15 ◽  
Author(s):  
Trinidad Montero ◽  
Rafael Ignacio Gatica ◽  
Navid Farassat ◽  
Rodrigo Meza ◽  
Cristian González-Cabrera ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Ventral Tegmental Area ◽  
Cell Body ◽  
Firing Pattern ◽  
Dendritic Tree ◽  
Dendritic Morphology ◽  
Substantia Nigra Pars Compacta ◽  
Ventral Tegmental ◽  
Firing Properties

The firing activity of ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) dopaminergic (DA) neurons is an important factor in shaping DA release and its role in motivated behavior. Dendrites in DA neurons are the main postsynaptic compartment and, along with cell body and axon initial segment, contribute to action potential generation and firing pattern. In this study, the organization of the dendritic domain in individual VTA and SNc DA neurons of adult male mice, and their relationship to in vivo spontaneous firing, are described. In comparison with dorsal VTA DA neurons, ventrally located VTA neurons (as measured by cell body location) possess a shorter total dendritic length and simpler dendritic architecture, and exhibit the most irregular in vivo firing patterns among DA neurons. In contrast, for DA neurons in the SNc, the higher irregularity of firing was related to a smaller dendritic domain, as measured by convex hull volumes. However, firing properties were also related to the specific regional distribution of the dendritic tree. Thus, VTA DA neurons with a larger extension of their dendritic tree within the parabrachial pigmented (PBP) nucleus fired more regularly compared with those with relatively more dendrites extending outside the PBP. For DA neurons in the SNc, enhanced firing irregularity was associated with a smaller proportion of dendrites penetrating the substantia nigra pars reticulata. These results suggest that differences in dendritic morphology contribute to the in vivo firing properties of individual DA neurons, and that the existence of region-specific synaptic connectivity rules that shape firing diversity.

scholarly journals The tectonigral pathway regulates appetitive locomotion in predatory hunting in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Meizhu Huang ◽  
Dapeng Li ◽  
Xinyu Cheng ◽  
Qing Pei ◽  
Zhiyong Xie ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Superior Colliculus ◽  
Dopamine Release ◽  
Dorsal Striatum ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Neuronal Circuitry ◽  
Locomotion Speed ◽  
Brain Circuit ◽  
Goal Directed Behavior

AbstractAppetitive locomotion is essential for animals to approach rewards, such as food and prey. The neuronal circuitry controlling appetitive locomotion is unclear. In a goal-directed behavior—predatory hunting, we show an excitatory brain circuit from the superior colliculus (SC) to the substantia nigra pars compacta (SNc) to enhance appetitive locomotion in mice. This tectonigral pathway transmits locomotion-speed signals to dopamine neurons and triggers dopamine release in the dorsal striatum. Synaptic inactivation of this pathway impairs appetitive locomotion but not defensive locomotion. Conversely, activation of this pathway increases the speed and frequency of approach during predatory hunting, an effect that depends on the activities of SNc dopamine neurons. Together, these data reveal that the SC regulates locomotion-speed signals to SNc dopamine neurons to enhance appetitive locomotion in mice.

Struktur und Efferenzen der Substantia nigra pars compacta beim idiopathischen Parkinson-Syndrom

2020 ◽  
Vol 88 (09) ◽  
pp. 591-599
Author(s):  
Peter Urban ◽  
Bjorn Falkenburger ◽  
Wolfgang H. Jost ◽  
Gerhard Ransmayr ◽  
Peter Riederer ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Substantia Nigra Pars Compacta

ZusammenfassungEs besteht Konsens, dass das neuropathologische Merkmal des idiopathischen Parkinson-Syndroms (IPS) der neuronale Zellverlust der Substantia nigra pars compacta (SNc) in Verbindung mit einer Lewy-Pathologie ist. Die transsynaptische Ausbreitung der Lewy-Pathologie wird als wesentlich in der Parkinson-Pathogenese angesehen. Daher ist die Kenntnis präexistenter neuroanatomischer Verbindungen der SNc wesentlich. Wir beschreiben hier neuere tierexperimentelle Befunde zu den afferenten und efferenten Projektionen der SNc und diskutieren die Evidenz für und gegen die sequentielle transsynaptische Ausbreitung der Lewy-Pathologie in der Pathogenese des IPS.

scholarly journals Substantia nigra neuromelanin magnetic resonance imaging in patients with different subtypes of Parkinson disease

2021 ◽  
Author(s):  
Lu Wang ◽  
Yayun Yan ◽  
Liyao Zhang ◽  
Yan Liu ◽  
Ruirui Luo ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Substantia Nigra ◽  
Parkinson Disease ◽  
Clinical Symptoms ◽  
Dopamine Neurons ◽  
Substantia Nigra Pars Compacta ◽  
Resonance Imaging ◽  
Mean Values

AbstractNeuromelanin (NM) is a dark pigment that mainly exists in neurons of the substantia nigra pars compacta (SNc). In Parkinson disease (PD) patients, NM concentration decreases gradually with degeneration and necrosis of dopamine neurons, suggesting potential use as a PD biomarker. We aimed to evaluate associations between NM concentration in in vivo SN and PD progression and different motor subtypes using NM magnetic resonance imaging (NM-MRI). Fifty-four patients with idiopathic PD were enrolled. Patients were divided into groups by subtypes with different clinical symptoms: tremor dominant (TD) group and postural instability and gait difficulty (PIGD) group. Fifteen healthy age-matched volunteers were enrolled as controls. All subjects underwent clinical assessment and NM-MRI examination. PD patients showed significantly decreased contrast-to-noise ratio (CNR) values in medial and lateral SN (P < 0.05) compared to controls. CNR values in lateral SN region decreased linearly with PD progression (P = 0.001). PIGD patients showed significant decreases in CNR mean values in lateral SN compared to TD patients (P = 0.004). Diagnostic accuracy of using lateral substantia nigra (SN) in TD and PIGD groups was 79% (sensitivity 76.5%, specificity 78.6%). NM concentration in PD patients decreases gradually during disease progression and differs significantly between PD subtypes. NM may be a reliable biomarker for PD severity and subtype identification.

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