Brain: Nucleus accumbens
Coronal section of one half of the brain. A coronal plane (also known as the frontal plane) is any vertical plane that divides the body into Anterior and Posterior (belly and back sections Nucleus accumbens not labeled, but labels are provided for caudate, putamen, and septum pellucidum. The caudate nucleus is a nucleus located within the Basal ganglia of the Brains of many animal species "Putamen" is also a botanical term for the stone in a Fruit, such as a Peach. The septum pellucidum (also called the septum lucidum) is a thin triangular vertical membrane that separates the Lateral ventricles of the Brain.
Medial surface, person facing to the left. In fields of Anatomy, anatomical terms of location are descriptive terms to help identify relative positions or directions within a species Nucleus accumbens is very roughly in the area labeled 34.
Latin	nucleus accumbens septi
NeuroNames	hier-259
MeSH	Nucleus+Accumbens
Dorlands/Elsevier	n_11/12580142

The nucleus accumbens (NAcc), also known as the accumbens nucleus or as the nucleus accumbens septi (Latin for nucleus leaning against the septum), is a collection of neurons within the forebrain. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. NeuroNames is a system of nomenclature for the human and/or macaque Brain. Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books Elsevier, the world's largest Publisher of Medical and Scientific literature, forms part of the Reed Elsevier group In Neuroanatomy, a nucleus is a Central nervous system structure that is composed mainly of Gray matter, and that acts as a hub or transit point for A septum ( Latin: something that encloses; plural Septa) is a partition separating two cavities or spaces Neurons (ˈnjuːɹɒn also known as neurones and nerve cells) are responsive cells in the Nervous system that process and transmit information In the Anatomy of the Brain of Vertebrates, the prosencephalon (or forebrain) is the Rostral -most (forward-most portion of the It is thought to play an important role in reward, laughter, pleasure, addiction and fear. Pleasure is commonly conceptualized as a positive experience Happiness, Entertainment, Enjoyment, ecstasy, and euphoria, but is hard The term " addiction " is used in many contexts to describe an obsession compulsion or excessive Physical dependence or psychological dependence such as Fear is an Emotional response to Threats and Danger. It is a basic survival mechanism occurring in response to a specific Stimulus, such as ^[1]

Each half of the brain has one nucleus accumbens. It is located where the head of the caudate and the anterior portion of the putamen meet just lateral to the septum pellucidum. The caudate nucleus is a nucleus located within the Basal ganglia of the Brains of many animal species "Putamen" is also a botanical term for the stone in a Fruit, such as a Peach. The septum pellucidum (also called the septum lucidum) is a thin triangular vertical membrane that separates the Lateral ventricles of the Brain. The nucleus accumbens and the olfactory tubercle collectively form the ventral striatum, which is part of the basal ganglia. Olfaction (also known as olfactics or smell) refers to the Sense of smell. The striatum is a subcortical (ie inside rather than on the outside part of the Telencephalon. The basal ganglia (or basal nuclei) are a group of nuclei in the Brain interconnected with the Cerebral cortex, Thalamus and ^[2]

The nucleus accumbens can be divided into two structures -- the nucleus accumbens core and the nucleus accumbens shell. These structures have different morphology and function.

Contents 1 Cell types 2 Output and input 3 Research 4 Additional images 5 References 6 External links

Cell types

The principal neuronal cell type found in the nucleus accumbens is the medium spiny neuron. The medium spiny neurons are a special type of inhibitory cells representing approximately 90% of the Neurons within the Corpus striatum of the Basal ganglia The neurotransmitter produced by these neurons is gamma-aminobutyric acid (GABA), one of the main inhibitory neurotransmitters of the central nervous system. See Chemical synapse for an introduction to concepts and terminology used in this article Gamma-aminobutyric acid (GABA is the chief inhibitory Neurotransmitter in the Mammalian Central nervous system. These neurons are also the main projection or output neurons of the nucleus accumbens.

While 95% of the neurons in the nucleus accumbens are medium spiny GABA-ergic projection neurons, other neuronal types are also found such as large aspiny cholinergic interneurons. A receptor is cholinergic if it uses Acetylcholine as its Neurotransmitter. An interneuron (also called association neuron, local circuit neuron or relay neuron) is a neuron which connects Afferent neurons and Efferent

Output and input

The output neurons of the nucleus accumbens send axon projections to the ventral analog of the globus pallidus, known as the ventral pallidum (VP). The globus pallidus ( Latin for "pale globe" is a sub- cortical structure of the Brain. The globus pallidus ( Latin for "pale globe" is a sub- cortical structure of the Brain. The VP, in turn, projects to the mediodorsal (MD) nucleus of the dorsal thalamus, which projects to the prefrontal cortex. The thalamus (from Greek θάλαμος = room chamber, IPA= /ˈθæləməs/ is a pair and symmetric part of the brain Other efferents from the nucleus accumbens include connections with the substantia nigra and pontine reticular formation. The substantia nigra ( Latin for "black substance" Sömmering) or locus niger is a heterogeneous portion of the midbrain, separating Major inputs to the nucleus accumbens include prefrontal association cortices, basolateral amygdala, and dopaminergic neurons located in the ventral tegmental area (VTA), which connect via the mesolimbic pathway. The la amygdalae ( Latin, also la corpus amygdaloideum, singular la amygdala, from Greek el αμυγδαλή grc-Latn amygdalē, 'almond' The ventral tegmentum or the ventral tegmental area (VTA ( tegmentum, Latin for covering) is part of the Midbrain, lying close to the Substantia The mesolimbic pathway is one of the Neural pathways in the Brain that links the Ventral tegmentum in the Midbrain to the Nucleus accumbens Thus the nucleus accumbens is often described as one part of a cortico-striato-thalamo-cortical loop.

Dopaminergic input from the VTA is thought to modulate the activity of neurons within the nucleus accumbens. These terminals are also the site of action of highly-addictive drugs such as cocaine and amphetamine, which cause a manifold increase in dopamine levels in the nucleus accumbens. Recreational drug use is the use of Psychoactive drugs for Recreational purposes rather than for work, medical or spiritual purposes Cocaine ( benzoylmethyl ecgonine) is a Crystalline Tropane Alkaloid that is obtained from the leaves of the Coca plant Amphetamine, and related drugs such as Methamphetamine are a group of drugs that act by increasing levels of Norepinephrine, Serotonin, and Dopamine Dopamine is a Hormone and Neurotransmitter occurring in a wide variety of animals including both vertebrates and invertebrates In addition to cocaine and amphetamine, almost every recreational drug has been shown to increase dopamine levels in the nucleus accumbens.

Research

In the 1950s, Olds and Milner implanted electrodes into the septal area of the rat and found that the rat chose to press a lever which stimulated it. It continued to prefer this even over stopping to eat or drink. This suggests that the area is the 'pleasure center' of the brain. ^[3]

Although the nucleus accumbens has traditionally been studied for its role in addiction, it plays an equal role in processing many rewards such as food and sex. A recent study found that it is involved in the regulation of emotions induced by music ^[4] , perhaps consequent to its role in mediating dopamine release. Music is an Art form in which the medium is Sound organized in Time. It also has roles in timing, and has long been considered to be the limbic-motor interface (Mogensen).

In April 2007, two research teams reported on having inserted electrodes into the nucleus accumbens in order to use deep brain stimulation to treat severe depression. In Neurotechnology, deep brain stimulation ( DBS) is a surgical treatment involving the implantation of a medical device called a Brain pacemaker Major depressive disorder, also known as major depression, unipolar depression, unipolar disorder, clinical depression, or simply depression ^[5]

Additional images

Dopamine and serotonin

References

External links

• The role of the nucleus accumbens in the reward circuit. Part of "The Brain From Top to Bottom. Technology Review is a magazine published by Technology Review Inc a media company owned by the Massachusetts Institute of Technology. " at thebrain. mcgill. ca
• BrainMaps at UCDavis nucleus%20accumbens

BrainMaps is an NIH -funded interactive zoomable high-resolution digital brain atlas and virtual microscope that is based on more than 20 million megapixels (50 terabytes

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