Medium Spiny Neurons
>”Medium spiny neurons (MSNs), also known as spiny projection neurons (SPNs), are a special type of GABAergic inhibitory cell representing 95% of neurons within the human striatum, a basal ganglia structure.[1] Medium spiny neurons have two primary phenotypes (characteristic types): D1-type MSNs of the direct pathway and D2-type MSNs of the indirect pathway.[1][2][3] Most striatal MSNs contain only D1-type or D2-type dopamine receptors, but a subpopulation of MSNs exhibit both phenotypes.” (From Wiki)
>”The firing activity of the main striatal neuron class, the “medium spiny projection neurons,” is highly regulated in adults. Despite exhibiting rich near-threshold activity (“UP states”) driven by excitatory cortical inputs, these neurons are usually silent. It seems likely that medium spiny neurons filter out uncorrelated afferent activity and fire only in response to precisely synchronized inputs.”
THC, D1-D2 Heteromers & MSNs
“This study highlights intriguing discoveries relevant to dopamine receptor signaling and cannabinoid-induced neuroadaptive changes in primate basal ganglia. (1) We provide abundant morphological evidence that dopamine D1 and D2 receptors form complexes in the dorsal striatum and NAc of mammalian species, including mouse, rat, nonhuman primate and human. Evolutionary differences were noted in the expression of dopamine D1-D2 heteromers, with heteromer abundance in the order human > primate > rat > mouse. In all these species, a higher number of MSNs expressing the D1-D2 heteromer was observed in the ventral striatum (i.e., NAc) than in the dorsal striatum. (2) THC increased the number of neurons expressing the D1-D2 heteromer in both regions of the striatum of nonhuman primate brain after chronic administration, from 35% or less, to approximately 80%, together with a 3-fold increase of heteromer density within individual neurons. (3) The chronic low-dose THC regimen led to a phenotypic change in MSNs indicating a reprogramming of these MSNs to co-express the characteristic markers of both striatonigral and striatopallidal neurons together with co-expression of D1 and D2 receptors.”
MSNs & the thalamocortical loop
>”Medium spiny neurons (MSNs) make up as much as 95% of cells within the striatum and send inhibitory projections to s
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Hi,
I have a class project where I am classifying neurons using electrophysiology data from the Allen Brain Institute. I am classifying them as being Spiny or Aspiny using a convolutional neural network. I mostly finished the project (it worked). I am wondering if spiny vs. aspiny classification using electrophysiology data has ever been done before and I have some results I can compare mine to.
I don't have a background in molecular neuroscience and I am not remotely with the literature. My brief search has not yielded anything useful. Can anyone point me in the right direction?
Thanks
https://doi.org/10.1186/s13041-021-00842-2
https://pubmed.ncbi.nlm.nih.gov/34479615
Abstract
The medium-chain fatty acids octanoic acid (C8) and decanoic acid (C10) are gaining attention as beneficial brain fuels in several neurological disorders. The protective effects of C8 and C10 have been proposed to be driven by hepatic production of ketone bodies. However, plasma ketone levels correlates poorly with the cerebral effects of C8 and C10, suggesting that additional mechanism are in place. Here we investigated cellular C8 and C10 metabolism in the brain and explored how the protective effects of C8 and C10 may be linked to cellular metabolism. Using dynamic isotope labeling, with [U-^(13) C]C8 and [U-^(13) C]C10 as metabolic substrates, we show that both C8 and C10 are oxidatively metabolized in mouse brain slices. The^(13) C enrichment from metabolism of [U-^(13) C]C8 and [U-^(13) C]C10 was particularly prominent in glutamine, suggesting that C8 and C10 metabolism primarily occurs in astrocytes. This finding was corroborated in cultured astrocytes in which C8 increased the respiration linked to ATP production, whereas C10 elevated the mitochondrial proton leak. When C8 and C10 were provided together as metabolic substrates in brain slices, metabolism of C10 was predominant over that of C8. Furthermore, metabolism of both [U-^(13) C]C8 and [U-^(13) C]C10 was unaffected by etomoxir indicating that it is independent of carnitine palmitoyltransferase I (CPT-1). Finally, we show that inhibition of glutamine synthesis selectively reduced^(13) C accumulation in GABA from [U-^(13) C]C8 and [U-^(13) C]C10 metabolism in brain slices, demonstrating that the glutamine generated from astrocyte C8 and C10 metabolism is utilized for neuronal GABA synthesis. Collectively, the results show that cerebral C8 and C10 metabolism is linked to the metabolic coupling of neurons and astrocytes, which may serve as a protective metabolic mechanism of C8 and C10 supplementation in neurological disorders.
------------------------------------------ Info ------------------------------------------
Open Access: True
Authors: Jens V. Andersen - Emil W. Westi - Emil Jakobsen - Nerea Urruticoechea - Karin Borges - Blanca I. Aldana -
Additional links:
[https://molecularbrain.biomedcentral.com/track/pdf/10.1186/s13041-021-00842-2](https://molecularbrain.biomedcentral.com/trac
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thank u for listening
This is sort of embarrassing but I never thought about it before. I know in general cells with spiny dendrites are excitatory. But I'm not sure why. What is the reason spiny dendrites are associated with exitatory cells?
Medium Spiny Neurons
>”Medium spiny neurons (MSNs), also known as spiny projection neurons (SPNs), are a special type of GABAergic inhibitory cell representing 95% of neurons within the human striatum, a basal ganglia structure.[1] Medium spiny neurons have two primary phenotypes (characteristic types): D1-type MSNs of the direct pathway and D2-type MSNs of the indirect pathway.[1][2][3] Most striatal MSNs contain only D1-type or D2-type dopamine receptors, but a subpopulation of MSNs exhibit both phenotypes.” (From Wiki)
>”The firing activity of the main striatal neuron class, the “medium spiny projection neurons,” is highly regulated in adults. Despite exhibiting rich near-threshold activity (“UP states”) driven by excitatory cortical inputs, these neurons are usually silent. It seems likely that medium spiny neurons filter out uncorrelated afferent activity and fire only in response to precisely synchronized inputs.”
THC, D1-D2 Heteromers & MSNs
>”This study highlights intriguing discoveries relevant to dopamine receptor signaling and cannabinoid-induced neuroadaptive changes in primate basal ganglia. (1) We provide abundant morphological evidence that dopamine D1 and D2 receptors form complexes in the dorsal striatum and NAc of mammalian species, including mouse, rat, nonhuman primate and human. Evolutionary differences were noted in the expression of dopamine D1-D2 heteromers, with heteromer abundance in the order human > primate > rat > mouse. In all these species, a higher number of MSNs expressing the D1-D2 heteromer was observed in the ventral striatum (i.e., NAc) than in the dorsal striatum. (2) THC increased the number of neurons expressing the D1-D2 heteromer in both regions of the striatum of nonhuman primate brain after chronic administration, from 35% or less, to approximately 80%, together with a 3-fold increase of heteromer density within individual neurons. (3) The chronic low-dose THC regimen led to a phenotypic change in MSNs indicating a reprogramming of these MSNs to co-express the characteristic markers of both striatonigral and striatopallidal neurons together with co-expression of D1 and D2 receptors.”
MSNs & the thalamocortical loop
>”Medium spiny neurons (MSNs) make up as much as 95% of cells within the striatum and send inhibitory
... keep reading on reddit ➡