Author Topic: the Substantia nigra (Dopamine neurons, learning, DRUG ADDICTION and emotion)  (Read 116 times)

Offline Chip (OP)

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source: https://neuroscientificallychallenged.com/blog/know-your-brain-substantia-nigra

Note: if you fuck with your reward system like I do with METH then expect some punishment too and possibly eventual malfunctions. Still, I devote my brain to science to I can study the impact of long-term (methyl)amphetamine use. If i had access to the prn (taken as required) usage of smarter MAOIWiki drugs, epinephrine and norepinephrine reuptake inhibitors then I could make the whole stimulant withdrawa experience so much easier but alas, no doctor will support this. Fucked up, right ?

Know your brain: Substantia nigra

November 15, 2014

Where is the substantia nigra ?



A CROSS-SECTION OF THE BRAINSTEM SHOWING THE TWO SUBSTANTIA NIGRAE.

The substantia nigra is a nucleus in the midbrainWiki that is considered part of the basal gangliaWiki.

It looks like a darkened streak in unstained brain tissue; this is where it gets its name, which is Latin for "black substance."

Although it is often referred to as one structure, the substantia nigra is actually made up of two anatomically and functionally distinct portions: the substantia nigra pars compacta and the substantia nigra pars reticulata.

Neurons in the pars compacta are much more densely packed together (or compact) than those in the pars reticulata.

What is the substantia nigra and what does it do?

Most of the dopamine neurons of the brain originate in the midbrain and are found in either the substantia nigra or the ventral tegmental areaWiki, which is located adjacent to the substantia nigra.

(The ventral tegmental area, or VTA, is found in the midbrain, situated next to the substantia nigra. ... It is one of the two major dopaminergic areas in the brain (the other being the substantia nigra). VTA dopamine neurons travel from the VTA to other areas of the brain in several major pathways)



The dopamine neurons in the substantia nigra express high levels of a pigment called neuromelanin, which accounts for their dark color.

These dopamine neurons, however, are found predominantly in the substantia nigra pars compactaWiki.

The pars reticulataWiki is instead populated largely by GABA neurons.



WATCH THIS 2-MINUTE NEUROSCIENCE VIDEO TO LEARN MORE ABOUT THE SUBSTANTIA NIGRA.

Many of the dopamine neurons of the substantia nigra project to the striatumWiki, another part of the basal ganglia that is made up of the caudate and putamen. In doing so they form a pathway called the nigrostriatal dopamine pathway that is thought to be crucial in the facilitation of movement.

(The striatum is referred collectively to the caudate, putamen, and nucleus accumbens; the structure has a striped appearance, which led to its name. It is part of the basal ganglia and involved in movement along with reward/motivation.)

The influence of the substantia nigra on movement is made apparent by observing the symptoms of Parkinson's disease, which are associated with the death of dopamine neurons in the substantia nigra pars compacta.

EDIT: This could also happen to METH users and could be related to GABA production anomalies but that's just a guess as there must always an interplay between dopamine a GABA (I think).

Although it still isn't clear what exactly causes neurodegeneration in Parkinson's disease, when a significant number of these neurons have died, the individual will likely start to experience movement-related problems like tremors, rigidity, slowness of movement, and postural instability--all hallmark symptoms of Parkinson's disease.

Being one of the major dopamine-producing areas of the brain, however, the substantia nigra has functions that extend beyond just motor control. It is also thought to play important roles in a number of other functions and behaviors, including learning, drug addiction, and emotion.

The striatum is also thought to be important to the processing of rewarding experiences and seems to be involved in the development of addiction.



The mesolimbic pathwayWiki, sometimes referred to as the reward pathway, is a dopaminergic pathway in the brain. The pathway connects the ventral tegmental area in the midbrain, to the ventral striatum of the basal ganglia in the forebrain. The ventral striatum includes the nucleus accumbens and the olfactory tubercle.

Had enough yet  ;) ?
« Last Edit: July 07, 2019, 07:32:58 AM by Chip »
Over 90% of all computer problems can be traced back to the interface between the keyboard and the chair !

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