The striatum (: striata) or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical

basal ganglia The basal ganglia (BG) or basal nuclei are a group of subcortical Nucleus (neuroanatomy), nuclei found in the brains of vertebrates. In humans and other primates, differences exist, primarily in the division of the globus pallidus into externa ...

. The striatum is a critical component of the

motor An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power gene ...

and

reward system The reward system (the mesocorticolimbic circuit) is a group of neural structures responsible for incentive salience (i.e., "wanting"; desire or craving for a reward and motivation), associative learning (primarily positive reinforcement and c ...

s; receives

glutamatergic Glutamatergic means "related to glutamate". A glutamatergic agent (or drug) is a chemical that directly modulates the excitatory amino acid (glutamate/aspartate) system in the body or brain. Examples include excitatory amino acid receptor agonist ...

and

dopaminergic Dopaminergic means "related to dopamine" (literally, "working on dopamine"), a common neurotransmitter. Dopaminergic substances or actions increase dopamine-related activity in the brain. Dopaminergic pathways, Dopaminergic brain pathways facil ...

inputs from different sources; and serves as the primary input to the rest of the basal ganglia. Functionally, the striatum coordinates multiple aspects of

cognition Cognition is the "mental action or process of acquiring knowledge and understanding through thought, experience, and the senses". It encompasses all aspects of intellectual functions and processes such as: perception, attention, thought, ...

, including both motor and action planning,

decision-making In psychology, decision-making (also spelled decision making and decisionmaking) is regarded as the Cognition, cognitive process resulting in the selection of a belief or a course of action among several possible alternative options. It could be ...

motivation Motivation is an mental state, internal state that propels individuals to engage in goal-directed behavior. It is often understood as a force that explains why people or animals initiate, continue, or terminate a certain behavior at a particul ...

reinforcement In Behaviorism, behavioral psychology, reinforcement refers to consequences that increase the likelihood of an organism's future behavior, typically in the presence of a particular ''Antecedent (behavioral psychology), antecedent stimulus''. Fo ...

, and reward perception. The striatum is made up of the

caudate nucleus The caudate nucleus is one of the structures that make up the corpus striatum, which is part of the basal ganglia in the human brain. Although the caudate nucleus has long been associated with motor processes because of its relation to Parkinso ...

and the

lentiform nucleus The lentiform nucleus (or lentiform complex, lenticular nucleus, or lenticular complex) are the putamen (laterally) and the globus pallidus (medially), collectively. Due to their proximity, these two structures were formerly considered one, howev ...

. However, some authors believe it is made up of

putamen The putamen (; from Latin, meaning "nutshell") is a subcortical nucleus (neuroanatomy), nucleus with a rounded structure, in the basal ganglia nuclear group. It is located at the base of the forebrain and above the midbrain. The putamen and c ...

, and ventral striatum. The lentiform nucleus is made up of the larger

, and the smaller

globus pallidus The globus pallidus (GP), also known as paleostriatum or dorsal pallidum, is a major component of the Cerebral cortex, subcortical basal ganglia in the brain. It consists of two adjacent segments, one external (or lateral), known in rodents simpl ...

. Strictly speaking the globus pallidus is part of the striatum. It is common practice, however, to implicitly exclude the globus pallidus when referring to striatal structures. In

primate Primates is an order (biology), order of mammals, which is further divided into the Strepsirrhini, strepsirrhines, which include lemurs, galagos, and Lorisidae, lorisids; and the Haplorhini, haplorhines, which include Tarsiiformes, tarsiers a ...

s, the striatum is divided into the ventral striatum and the dorsal striatum, subdivisions that are based upon function and connections. The

ventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

striatum consists of the

nucleus accumbens The nucleus accumbens (NAc or NAcc; also known as the accumbens nucleus, or formerly as the ''nucleus accumbens septi'', Latin for ' nucleus adjacent to the septum') is a region in the basal forebrain rostral to the preoptic area of the hypo ...

and the olfactory tubercle. The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

striatum consists of the

and the

. A

white matter White matter refers to areas of the central nervous system that are mainly made up of myelinated axons, also called Nerve tract, tracts. Long thought to be passive tissue, white matter affects learning and brain functions, modulating the distr ...

nerve tract A nerve tract is a bundle of nerve fibers (axons) connecting Nucleus (neuroanatomy), nuclei of the central nervous system. In the peripheral nervous system, this is known as a nerve fascicle, and has associated nervous tissue, connective tissue. T ...

(the

internal capsule The internal capsule is a paired white matter structure, as a two-way nerve tract, tract, carrying afferent nerve fiber, ascending and efferent nerve fiber, descending axon, fibers, to and from the cerebral cortex. The internal capsule is situate ...

) in the dorsal striatum separates the

and the

. Anatomically, the term ''striatum'' describes its striped (striated) appearance of grey-and-white matter.

Structure

The striatum is the largest structure of the

. The striatum is divided into two subdivisions, a ventral striatum and a dorsal striatum, based upon function and connections. It is also divisible into a matrix and embedded striosomes.

Ventral striatum

The ventral striatum is composed of the

and the olfactory tubercle. The nucleus accumbens is made up of the nucleus accumbens core and the nucleus accumbens shell, which differ by neural populations. The olfactory tubercle receives input from the

olfactory bulb The olfactory bulb (Latin: ''bulbus olfactorius'') is a neural structure of the vertebrate forebrain involved in olfaction, the sense of smell. It sends olfactory information to be further processed in the amygdala, the orbitofrontal cortex (OF ...

but has not been shown to play a role in processing smell. In non-primate species, the

islands of Calleja The islands of Calleja (; IC, ISC, or IClj) are a group of neural granule cells located within the ventral striatum in the brains of most animals. This region of the brain is part of the limbic system, where it aids in the reinforcing effects of r ...

are included. The ventral striatum is associated with the

limbic system The limbic system, also known as the paleomammalian cortex, is a set of brain structures located on both sides of the thalamus, immediately beneath the medial temporal lobe of the cerebrum primarily in the forebrain.Schacter, Daniel L. 2012. ''P ...

and has been implicated as a vital part of the

circuitry An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow. It is a type of electric ...

for decision making and reward-related behavior.

Dorsal striatum

The dorsal striatum is composed of the

and the

. Primarily it mediates cognition and involves motor and executive function. The dorsal striatum can be further subdivided into the dorsomedial striatum, and the dorsolateral striatum. Both of these areas have different roles in the acquisition of learnt behaviour and skill formation. The dorsomedial region receives projections from the frontal and the parietal cortices. The dorsolateral region receives projections from the sensorimotor cortex.

Matrix and striosomes

Neurochemistry Neurochemistry is the study of chemicals, including neurotransmitters and other molecules such as psychopharmaceuticals and neuropeptides, that control and influence the physiology of the nervous system. This particular field within neuroscience e ...

studies have used staining techniques on the striatum that have identified two distinct striatal compartments, the matrix, and the striosome (or patch). The matrix is seen to be rich in

acetylcholinesterase Acetylcholinesterase (HUGO Gene Nomenclature Committee, HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme th ...

, while the embedded striosomes are acetylcholinesterase-poor. The matrix forms the bulk of the striatum, and receives input from most areas of the cerebral cortex. Clusters of neurons in the matrix, called matrisomes receive a similar input. Their output goes to both regions of the globus pallidus and to the substantia nigra pars reticulata. The striosomes receive input from the prefrontal cortex and give outputs to the substantia nigra pars compacta. There are more striosomes present in the dorsal striatum making up 10-15% of the striatal volume, than in the ventral striatum.

Cell types

Types of cells in the striatum include: * Medium spiny neurons (MSNs), which are the principal neurons of the striatum. They are

GABAergic In molecular biology and physiology, something is GABAergic or GABAnergic if it pertains to or affects the neurotransmitter gamma-aminobutyric acid (GABA). For example, a synapse is GABAergic if it uses GABA as its neurotransmitter, and a GABAergic ...

and, thus, are classified as inhibitory neurons. Medium spiny projection neurons comprise 95% of the total neuronal population of the human striatum. Medium spiny neurons have two characteristic types: D1-type MSNs and D2-type MSNs. A subpopulation of MSNs contain both D1-type and D2-type receptors, with approximately 40% of striatal MSNs expressing both DRD1 and DRD2

mRNA In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of Protein biosynthesis, synthesizing a protein. mRNA is ...

. *

Cholinergic Cholinergic agents are compounds which mimic the action of acetylcholine and/or butyrylcholine. In general, the word " choline" describes the various quaternary ammonium salts containing the ''N'',''N'',''N''-trimethylethanolammonium cation ...

interneurons Interneurons (also called internuncial neurons, association neurons, connector neurons, or intermediate neurons) are neurons that are not specifically motor neurons or sensory neurons. Interneurons are the central nodes of neural circuits, ena ...

release acetylcholine, which has a variety of important effects in the striatum. In humans, other primates, and rodents, these interneurons respond to salient environmental stimuli with stereotyped responses that are temporally aligned with the responses of dopaminergic neurons of the

substantia nigra The substantia nigra (SN) is a basal ganglia structure located in the midbrain that plays an important role in reward and movement. ''Substantia nigra'' is Latin for "black substance", reflecting the fact that parts of the substantia nigra a ...

. The large aspiny cholinergic interneurons themselves are affected by dopamine through D5 dopamine receptors. Dopamine also directly controls communication between cholinergic interneurons. * There are many types of GABAergic interneurons. The best known are

parvalbumin Parvalbumin (PV) is a calcium-binding protein with low molecular weight (typically 9–11 kDa). In humans, it is encoded by the ''PVALB'' gene. It is a member of the albumin family; it is named for its size (''parv-'', from Latin ' which means " ...

expressing interneurons, also known as fast-spiking interneurons, which participate in powerful feedforward inhibition of principal neurons. Also, there are GABAergic interneurons that express

tyrosine hydroxylase Tyrosine hydroxylase or tyrosine 3-monooxygenase is the enzyme responsible for catalyzing the conversion of the amino acid L-tyrosine to L-3,4-dihydroxyphenylalanine (L-DOPA). It does so using molecular oxygen (O2), as well as iron (Fe2+) and ...

somatostatin Somatostatin, also known as growth hormone-inhibiting hormone (GHIH) or by #Nomenclature, several other names, is a peptide hormone that regulates the endocrine system and affects neurotransmission and cell proliferation via interaction with G ...

, nitric oxide synthase and neuropeptide-y. Recently, two types of neuropeptide-y expressing GABAergic interneurons have been described in detail, one of which translates synchronous activity of cholinergic interneurons into inhibition of principal neurons. These

neuron A neuron (American English), neurone (British English), or nerve cell, is an membrane potential#Cell excitability, excitable cell (biology), cell that fires electric signals called action potentials across a neural network (biology), neural net ...

s of the striatum are not distributed evenly. There are two regions of

neurogenesis Neurogenesis is the process by which nervous system cells, the neurons, are produced by neural stem cells (NSCs). This occurs in all species of animals except the porifera (sponges) and placozoans. Types of NSCs include neuroepithelial cells ( ...

in the brain – the subventricular zone (SVZ) in the

lateral ventricle The lateral ventricles are the two largest ventricular system, ventricles of the brain and contain cerebrospinal fluid. Each cerebral hemisphere contains a lateral ventricle, known as the left or right lateral ventricle, respectively. Each later ...

s, and the

dentate gyrus The dentate gyrus (DG) is one of the subfields of the hippocampus, in the hippocampal formation. The hippocampal formation is located in the temporal lobe of the brain, and includes the hippocampus (including CA1 to CA4) subfields, and other su ...

in the

hippocampal formation The hippocampal formation is a compound structure in the medial temporal lobe of the brain. It forms a c-shaped bulge on the floor of the inferior horn of the lateral ventricle. Typically, the hippocampal formation is said to included the dent ...

. Neuroblasts that form in the lateral ventricle adjacent to the striatum, integrate in the striatum. This has been noted in the human striatum following an

ischemic stroke Stroke is a medical condition in which poor blood flow to a part of the brain causes cell death. There are two main types of stroke: ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to stop ...

. Injury caused to the striatum stimulates the migration of neuroblasts from the SVZ, to the striatum, where they differentiate into adult neurons. The normal passage of SVZ neuroblasts is to the

but this traffic is diverted to the striatum after an ischemic stroke. However, few of the new developed neurons survive.

Inputs

The largest connection is from the

cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...

, in terms of cell axons. Many parts of the

neocortex The neocortex, also called the neopallium, isocortex, or the six-layered cortex, is a set of layers of the mammalian cerebral cortex involved in higher-order brain functions such as sensory perception, cognition, generation of motor commands, ...

innervate A nerve is an enclosed, cable-like bundle of nerve fibers (called axons). Nerves have historically been considered the basic units of the peripheral nervous system. A nerve provides a common pathway for the electrochemical nerve impulses called ...

the dorsal striatum. The cortical

pyramidal neurons Pyramidal cells, or pyramidal neurons, are a type of multipolar neuron found in areas of the brain including the cerebral cortex, the hippocampus, and the amygdala. Pyramidal cells are the primary excitation units of the mammalian prefrontal cort ...

projecting to the striatum are located in layers II-VI, with the most dense projections come from layer V. They end mainly on the

dendritic spine A dendritic spine (or spine) is a small membrane protrusion from a neuron's dendrite that typically receives input from a single axon at the synapse. Dendritic spines serve as a storage site for synaptic strength and help transmit electrical sign ...

s of the spiny neurons. They are

, exciting striatal neurons. The striatum is seen as having its own internal microcircuitry. The ventral striatum receives direct input from multiple regions in the

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. It is the largest site of Neuron, neural integration in the central nervous system, and plays ...

and limbic structures such as the

amygdala The amygdala (; : amygdalae or amygdalas; also '; Latin from Greek language, Greek, , ', 'almond', 'tonsil') is a paired nucleus (neuroanatomy), nuclear complex present in the Cerebral hemisphere, cerebral hemispheres of vertebrates. It is c ...

thalamus The thalamus (: thalami; from Greek language, Greek Wikt:θάλαμος, θάλαμος, "chamber") is a large mass of gray matter on the lateral wall of the third ventricle forming the wikt:dorsal, dorsal part of the diencephalon (a division of ...

, and

hippocampus The hippocampus (: hippocampi; via Latin from Ancient Greek, Greek , 'seahorse'), also hippocampus proper, is a major component of the brain of humans and many other vertebrates. In the human brain the hippocampus, the dentate gyrus, and the ...

, as well as the

entorhinal cortex The entorhinal cortex (EC) is an area of the brain's allocortex, located in the medial temporal lobe, whose functions include being a widespread network hub for memory, navigation, and the perception of time.Integrating time from experience in t ...

and the

inferior temporal gyrus The inferior temporal gyrus is one of three gyri of the temporal lobe and is located below the middle temporal gyrus, connected behind with the inferior occipital gyrus; it also extends around the infero-lateral border on to the inferior surface o ...

. Its primary input is to the

system. Additionally, the

mesolimbic pathway The mesolimbic pathway, 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 v ...

projects from the

ventral tegmental area The ventral tegmental area (VTA) (tegmentum is Latin for ''covering''), also known as the ventral tegmental area of Tsai, or simply ventral tegmentum, is a group of neurons located close to the midline on the floor of the midbrain. The VTA is th ...

to the

of the ventral striatum. Another well-known afferent is the nigrostriatal connection arising from the neurons of the

pars compacta. While cortical axons synapse mainly on spine heads of spiny neurons, nigral axons synapse mainly on spine shafts. In primates, the thalamostriatal afferent comes from the central median-parafascicular complex of the

(see primate basal ganglia system). This afferent is glutamatergic. The participation of truly intralaminar neurons is much more limited. The striatum also receives afferents from other elements of the basal ganglia such as the subthalamic nucleus (glutamatergic) or the external globus pallidus (

Targets

The primary outputs of the ventral striatum project to the

ventral pallidum The ventral pallidum (VP) is a structure within the basal ganglia of the brain. It is an output nucleus whose fibres project to thalamic nuclei, such as the ventral anterior nucleus, the ventral lateral nucleus, and the medial dorsal nucleus ...

, then the

medial dorsal nucleus The medial dorsal nucleus (or mediodorsal nucleus of thalamus, dorsomedial nucleus, dorsal medial nucleus, or medial nucleus group) is a large nucleus in the thalamus. It is separated from the other thalamic nuclei by the internal medullary lam ...

of the

, which is part of the

frontostriatal circuit Frontostriatal circuits are neural pathways that connect frontal lobe regions with the striatum and mediate motor, cognitive, and behavioural functions within the brain. They receive inputs from dopaminergic, serotonergic, noradrenergic, and ch ...

. Additionally, the ventral striatum projects to the

, and substantia nigra pars reticulata. Some of its other outputs include projections to the extended amygdala,

lateral hypothalamus The lateral hypothalamus (LH), also called the lateral hypothalamic area (LHA), contains the primary orexinergic nucleus within the hypothalamus that widely projects throughout the nervous system; this system of neurons mediates an array of cogni ...

, and pedunculopontine nucleus. Striatal outputs from both the dorsal and ventral components are primarily composed of

medium spiny neuron Medium spiny neurons (MSNs), also known as spiny projection neurons (SPNs), are a special type of inhibitory GABAergic neuron representing approximately 90% of neurons within the human striatum, a basal ganglia structure. Medium spiny neurons h ...

s (MSNs), a type of

projection neuron Projection fibers consist of efferent and afferent fibers uniting the cortex with the lower parts of the brain and with the spinal cord. In human neuroanatomy, bundles of axons (nerve fibers) called nerve tracts, within the brain, can be cate ...

, which have two primary

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...

s: "indirect" MSNs that express D2-like receptors and "direct" MSNs that express D1-like receptors. The main nucleus of the basal ganglia is the striatum which projects directly to the globus pallidus via a pathway of striatopallidal fibers. The striato-pallidal pathway has a whitish appearance due to the myelinated fibers. This projection comprises successively the external globus pallidus (GPe), the internal globus pallidus (GPi), the

pars compacta The pars compacta (SNpc, SNc) is one of two subdivisions of the ''substantia nigra'' of the midbrain (the other being the pars reticulata); it is situated medial to the ''pars reticulata''. It is formed by dopaminergic neurons. It projects to th ...

of the

(SNc), and the

pars reticulata The pars reticulata (SNpr) is a portion of the substantia nigra and is located lateral to the pars compacta. Most of the neurons that project out of the pars reticulata are inhibitory GABAergic neurons (i.e., these neurons release GABA, which is ...

of substantia nigra (SNr). The neurons of this projection are inhibited by GABAergic synapses from the dorsal striatum. Among these targets, the GPe does not send axons outside the system. Others send axons to the

superior colliculus In neuroanatomy, the superior colliculus () is a structure lying on the tectum, roof of the mammalian midbrain. In non-mammalian vertebrates, the Homology (biology), homologous structure is known as the optic tectum or optic lobe. The adjective f ...

. Two others comprise the output to the thalamus, forming two separate channels: one through the internal segment of the globus pallidus to the ventral oralis nuclei of the thalamus and from there to the cortical

supplementary motor area The supplementary motor area (SMA) is a part of the motor cortex of primates that contributes to the control of movement. It is located on the midline surface of the hemisphere just in front of (anterior to) the primary motor cortex leg representa ...

and another through the substantia nigra to the ventral anterior nuclei of the thalamus and from there to the

frontal cortex The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere (in front of the parietal lobe and the temporal lobe). It is parted from the parietal lobe by a groove betw ...

and the occulomotor cortex.

Blood supply

Deep penetrating striate arteries supply blood to the striatum. These arteries include the recurrent artery of Heubner arising from the

anterior cerebral artery The anterior cerebral artery (ACA) is one of a pair of cerebral arteries that supplies oxygenated blood to most midline portions of the frontal lobes and superior medial parietal lobes of the brain. The two anterior cerebral arteries arise from th ...

, and the lenticulostriate arteries arising from the

middle cerebral artery The middle cerebral artery (MCA) is one of the three major paired cerebral artery, cerebral arteries that supply blood to the cerebrum. The MCA arises from the internal carotid artery and continues into the lateral sulcus where it then branches an ...

Function

The ventral striatum, and the

in particular, primarily mediates reward, cognition,

, and

motivational salience Motivational salience is a cognitive process and a form of attention that ''motivates'' or propels an individual's behavior towards or away from a particular object, perceived event or outcome. Motivational salience regulates the intensity of b ...

. By contrast, the dorsal striatum primarily mediates cognition involving motor function, certain

executive functions In cognitive science and neuropsychology, executive functions (collectively referred to as executive function and cognitive control) are a set of cognitive processes that support goal-directed behavior, by regulating thoughts and actions thro ...

(e.g.,

inhibitory control Inhibitory control, also known as response inhibition, is a cognitive process – and, more specifically, an executive function – that permits an individual to inhibit their impulses and natural, habitual, or dominant behavioral re ...

and

impulsivity In psychology, impulsivity (or impulsiveness) is a tendency to act on a whim, displaying behavior characterized by little or no forethought, reflection, or consideration of the consequences. Impulsive actions are typically "poorly conceived, pre ...

), and stimulus-response learning. There is a small degree of overlap, as the dorsal striatum is also a component of the

that, along with the nucleus accumbens core, mediates the encoding of new motor programs associated with future reward acquisition (e.g., the conditioned motor response to a reward cue). The striatum is also thought to play a role in an at least partially dissociable executive control network for language, applied to both verbal working memory and verbal attention. These models take the form of a frontal-striatal network for language processing. While the striatum is often not included in models of

language processing In psycholinguistics, language processing refers to the way humans use words to communicate ideas and feelings, and how such communications are processed and understood. Language processing is considered to be a uniquely human ability that is ...

, as most models only include cortical regions, integrative models are becoming more popular in light of imaging studies, lesion studies on aphasic patients, and studies of language disorders concomitant with diseases known to affect the striatum like

Parkinson's Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become more prevalen ...

and Huntington's disease. Metabotropic

dopamine receptors Dopamine receptors are a class of G protein-coupled receptors that are prominent in the vertebrate central nervous system (CNS). Dopamine receptors activate different effectors through not only G-protein coupling, but also signaling through diff ...

are present both on spiny neurons and on cortical axon terminals.

Second messenger Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules—the first messengers. (Intercellular signals, a non-local form of cell signaling, encompassing both first m ...

cascades triggered by activation of these dopamine receptors can modulate pre- and postsynaptic function, both in the short term and in the long term. In humans, the striatum is activated by stimuli associated with reward, but also by

aversive In psychology, aversives are suffering, unpleasant Stimulus (physiology), stimuli that induce changes in behavior via negative reinforcement or positive punishment (psychology), punishment. By applying an aversive immediately before or after a be ...

novel A novel is an extended work of narrative fiction usually written in prose and published as a book. The word derives from the for 'new', 'news', or 'short story (of something new)', itself from the , a singular noun use of the neuter plural of ...

, unexpected, or intense stimuli, and cues associated with such events.

fMRI Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area o ...

evidence suggests that the common property linking these stimuli, to which the striatum is reacting, is salience under the conditions of presentation. A number of other brain areas and circuits are also related to reward, such as frontal areas. Functional maps of the striatum reveal interactions with widely distributed regions of the cerebral cortex important to a diverse range of functions. The interplay between the striatum and the

prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) covers the front part of the frontal lobe of the cerebral cortex. It is the association cortex in the frontal lobe. The PFC contains the Brodmann areas BA8, BA9, BA10, BA11, BA12, ...

is relevant for behavior, particularly adolescent development as proposed by the dual systems model.

Clinical significance

Parkinson's disease and other movement disorders

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...

results in loss of dopaminergic innervation to the dorsal striatum (and other basal ganglia) and a cascade of consequences.

Atrophy Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), malnutrition, poor nourishment, poor circulatory system, circulation, loss of hormone, ...

of the striatum is also involved in

Huntington's disease Huntington's disease (HD), also known as Huntington's chorea, is an incurable neurodegenerative disease that is mostly Genetic disorder#Autosomal dominant, inherited. It typically presents as a triad of progressive psychiatric, cognitive, and ...

, and

movement disorder Movement disorders are clinical syndromes with either an excess of movement or a paucity of voluntary and involuntary movements, unrelated to weakness or spasticity. Movement disorders present with extrapyramidal symptoms and are caused by basa ...

s such as

chorea Chorea, or (rarely) choreia, () is an abnormal involuntary movement disorder, characterized by quick movements of the hands or feet. It is one of a group of neurological disorders called dyskinesias. The term ''chorea'' is derived , as the move ...

, choreoathetosis, and dyskinesias. These have also been described as ''circuit disorders'' of the basal ganglia.

Addiction

Overview of reward structures in the human brain

Addiction Addiction is a neuropsychological disorder characterized by a persistent and intense urge to use a drug or engage in a behavior that produces natural reward, despite substantial harm and other negative consequences. Repetitive drug use can ...

, a disorder of the brain's

, arises through the overexpression of DeltaFosB (ΔFosB), a

transcription factor In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription (genetics), transcription of genetics, genetic information from DNA to messenger RNA, by binding t ...

, in the D1-type

s of the

ventral striatum The striatum (: striata) or corpus striatum is a cluster of interconnected nuclei that make up the largest structure of the subcortical basal ganglia. The striatum is a critical component of the motor and reward systems; receives glutamater ...

. ΔFosB is an inducible gene which is increasingly expressed in the

as a result of repeatedly using an addictive drug or overexposure to other addictive stimuli.

Schizophrenia spectrum disorders

The mesolimbic hypothesis of

schizophrenia Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, f ...

has long emphasized the role of hyperdopaminergia in the

, which extends from the

to the ventral striatum. Abnormally elevated dopaminergic transmission in this pathway has been associated with the emergence of positive symptoms, such as hallucinations and delusions. Most

antipsychotic Antipsychotics, previously known as neuroleptics and major tranquilizers, are a class of Psychiatric medication, psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), p ...

treatments exert their effects by reducing dopamine binding to receptors in this region. More recent evidence, however, suggests that the pathway from the

dorsal striatum may also play a significant role in the pathophysiology of

. This has led to the development of the mesostriatal hypothesis, which expands the focus beyond the ventral striatum to include dopaminergic dysfunction in the dorsal components of the striatum and could help accounting for the negative and cognitive symptoms.

Bipolar disorder

An association has been observed between striatal expression of variants of the PDE10A gene and some

bipolar I disorder Bipolar I disorder (BD-I; pronounced "type one bipolar disorder") is a type of bipolar spectrum disorder characterized by the occurrence of at least one manic episode, with or without mixed or psychotic features. Most people also, at other ti ...

patients. Variants of other genes, DISC1 and GNAS, have been associated with bipolar II disorder.

Autism spectrum disorder

Autism spectrum disorder Autism, also known as autism spectrum disorder (ASD), is a neurodevelopmental disorder characterized by differences or difficulties in social communication and interaction, a preference for predictability and routine, sensory processing di ...

(ASD) is characterized by cognitive inflexibility and poor understanding of social systems. This inflexible behavior originates in defects in the pre-frontal cortex as well as the striatal circuits. The defects in the striatum seem to specifically contribute to the motor, social and communication impairments seen in ASD patients. In mice which have an ASD-like phenotype induced via the overexpression of the eukaryotic initiation of translation factor 4E, it has been shown that these defects seem to stem from the reduced ability to store and process information in the striatum, which leads to the difficulty seen in forming new motor patterns, as well as disengaging from existing ones.

Dysfunction

Dysfunction in the ventral striatum can lead to a variety of disorders, most notably depression and obsessive-compulsive disorder. Because of its involvement in reward pathways, the ventral striatum has also been implicated in playing a critical role in addiction. It has been well established that the ventral striatum is strongly involved in mediating the reinforcing effects of drugs, especially stimulants, through dopaminergic stimulation.

Language disorders

Lesions to the striatum have been associated with deficits in speech production and comprehension. While striatal damage can impact all levels of language, damage can broadly be characterized as affecting the ability to manipulate linguistic units and rules, resulting in the promotion of default linguistic forms in conflicting situations in which selection, inhibition, and monitoring load is increased. Two subregions of the striatum have been shown to be particularly important in language: the

and left

. Lesions localized to the caudate nucleus, as well as direct electrical stimulation, can result in lexical paraphasias and perservations (continuations of an utterance after the stimulus has ceased), which is associated with inhibited executive control, in the sense that executive control allows for the selection of the best choice among competing alternatives). Stimulation of the putamen results in the inhibition of articulatory sequences and the inability to initiate motor speech commands.

History

In the seventeenth and eighteenth centuries, the term ''corpus striatum'' was used to designate many distinct, deep, infracortical elements of the cerebral hemisphere. Etymologically, it is derived from (Latin) ''striatus'' = "grooved, striated" and the English ''striated'' = having parallel lines or grooves on the surface. In 1876

David Ferrier Sir David Ferrier FRS (13 January 1843 – 19 March 1928) was a pioneering Scottish neurologist and psychologist. Ferrier conducted experiments on the brains of animals such as monkeys and in 1881 became the first scientist to be prosecuted ...

contributed decades of research to the subject; concluding that the corpus striatum was vital in the "organization and generation of voluntary movement". In 1941, Cécile and Oskar Vogt simplified the nomenclature by proposing the term ''striatum'' for all elements in the

built with striatal elements: the

, the

, and the fundus striati, which is the ventral part linking the two preceding together ventrally to the inferior part of the

. The term ''neostriatum'' was coined by comparative anatomists comparing the subcortical structures between vertebrates, because it was thought to be a phylogenetically newer section of the corpus striatum. The term is still used by some sources, including

Medical Subject Headings Medical Subject Headings (MeSH) is a comprehensive controlled vocabulary for the purpose of indexing Academic journal, journal articles and books in the Life science, life sciences. It serves as a thesaurus of index terms that facilitates searc ...

Other animals

bird Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

s the term used was the ''paleostriatum augmentatum'', and in the new avian terminology listing (as of 2002) for ''neostriatum'' this has been changed to the '' nidopallium''. In non-primate species, the

are included in the ventral striatum.

Additional images

File:Striatum coronal sections.gif, Striatum highlighted in green on coronal T1 MRI images File:Striatum sagittal sections.gif, Striatum highlighted in green on sagittal T1 MRI images File:Striatum transversal sections.gif, Striatum highlighted in green on transversal T1 MRI images

References

External links

* * * * https://web.archive.org/web/20131029195257/http://www.nimh.nih.gov/images/news-items/r1_braindorsal1.jpg * https://web.archive.org/web/20090914200329/http://www.hnl.bcm.tmc.edu/fmri.html {{Authority control Cerebrum Basal ganglia Addiction

Structure

Ventral striatum

Dorsal striatum

Matrix and striosomes

Cell types

Inputs

Targets

Blood supply

Function

Clinical significance

Parkinson's disease and other movement disorders

Addiction

Schizophrenia spectrum disorders

Bipolar disorder

Autism spectrum disorder

Dysfunction

Language disorders

History

Other animals

See also

Additional images

References

External links