Wikipedia

Putamen

"Putamen" is also abotanicalterm for the stone in afruit,such as apeach.

Theputamen(/pjuˈteɪmən/;fromLatin,meaning "nutshell" ) is a subcorticalnucleuswith a rounded structure, in thebasal ganglianuclear group. It is located at the base of theforebrainand above themidbrain.

Putamen
Putamen (in red) shown within the brain
Coronal section of brain through intermediate mass ofthird ventricle.(Putamen labeled at top.)
Details
Part ofDorsal striatum
Identifiers
MeSHD011699
NeuroNames230
NeuroLexIDbirnlex_809
TA98A14.1.09.507
TA25566
FMA61834
Anatomical terms of neuroanatomy

The putamen andcaudate nucleustogether form thedorsal striatum.Through various pathways, the putamen is connected to thesubstantia nigra,theglobus pallidus,theclaustrum,and thethalamus,in addition to many regions of thecerebral cortex.A primary function of the putamen is to regulate movements at various stages such as in preparation and execution; and to influence various types oflearning.It employsGABA,acetylcholine,andenkephalinto perform its functions. The putamen also plays a role inneurodegenerative diseases,such asParkinson's disease.

History

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The word "putamen" is fromLatin,referring to that which "falls off in pruning", from "putare", meaning "to prune, to think, or to consider".[1]

MostMRIresearch was focused broadly on the basal ganglia as a whole, for reasons such as poor resolution or hemorrhage within the putamen. Later studies have focused on the basal ganglia and relevant brain-behavior relationships. In the 1970s, the firstsingle-unit recordingswere carried out withmonkeys,monitoringpallidalneuronalactivity related to movement. Since then, more extensiveneuronal tracing,stimulation, and imaging research methods includingfunctional MRI,anddiffusion weighted MRIthat allow for investigation of the putamen have been developed.

Anatomy

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Globus pallidus (lower left) and putamen (upper right).H&E-LFB stain.

The putamen is a structure in theforebrain.Along with thecaudate nucleusit forms thedorsal striatum.The caudate and putamen contain the same types of neurons and circuits – many neuroanatomists consider the dorsal striatum to be a single structure, divided into two parts by a large fiber tract, theinternal capsule,passing through the middle. The putamen, together with theglobus pallidus,makes up thelentiform nucleus.The putamen is the outermost portion of thebasal ganglia.These are a group of nuclei in the brain that are interconnected with thecerebral cortex,thalamus,andbrainstem.The basal ganglia include thestriatum,substantia nigra,nucleus accumbens,and thesubthalamic nucleus.

Inmammals,the basal ganglia are associated withmotor control,cognition,emotions,learning,and domain-general functions important for executive functioning as well as support for domain-specific languages. The basal ganglia are located bilaterally, and haverostralandcaudaldivisions. The putamen is located in the rostral division as part of thestriatum.The basal ganglia receive input from the cerebral cortex, via the striatum.

This is a transverse section of the striatum from a structural MR image. The striatum includes the caudate nucleus (top) and putamen (right) and the globus pallidus (left).

Caudate nucleus

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The caudate works with the putamen to receive the input fromcerebral cortex.Collectively, they can be considered the "entrance" to the basal ganglia. Projections from the putamen reach the caudate directly via the caudolenticular grey bridges. The putamen and caudate are jointly connected with thesubstantia nigra,however the caudate outputs more densely to thesubstantia nigrapars reticulata while the putamen sends more afferents to the internalglobus pallidus.

Substantia nigra

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The substantia nigra contains two parts: the substantia nigra pars compacta (SNpc) and the substantia nigra pars reticulata (SNpr). The SNpc obtains input from the putamen and caudate, and sends information back. The SNpr also obtains input from the putamen and caudate. However, it sends the input outside the basal ganglia to control head andeye movements.The SNpc produces dopamine, which is crucial for movements. The SNpc degenerates duringParkinson's disease.[2]

Globus pallidus

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The globus pallidus contains two parts: theexternal globus pallidus(GPe) and theinternal globus pallidus(GPi). Both regions acquire input from the putamen and caudate and communicate with the subthalamic nucleus. However, mostly the GPi sends GABAergic inhibitory output to the thalamus. The GPi also sends projections to parts of the midbrain, which have been assumed to affect posture control.[2]

Physiology

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Types of pathways

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The putamen (and striatum in general) has numerous, parallel circuits that allow for cortico-subcortico-cortico communication loops. These have been described, broadly, as the direct, indirect, and hyper direct pathways. GABAergic projections of the putamen have an inhibitory effect on the thalamus. Thalamic projections from the centromedian and parafascicular nuclei have an excitatory effect on the putamen. Unlike the thalamus, which has broad reciprocal connectivity, cortical projections with the putamen are afferent, thus sending information as opposed to receiving it. Cortical communication is accomplished via multi-fiber pathways as outlined previously (i.e. via other subcortical structures).

Dopamine

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Dopamine is a neurotransmitter that has a dominant role in the putamen, most of it is supplied from the substantia nigra. When acell bodyof aneuron(in the putamen or caudate nuclei) fires anaction potential,dopamine is released from thepresynaptic terminal.Since projections from the putamen and caudate nucleimodulatethedendritesof the substantia nigra, the dopamine influences the substantia nigra, which affectsmotor planning.This same mechanism is involved indrug addiction[citation needed].In order to control the amount of dopamine in thesynaptic cleft,and the amount of dopamine binding topost synaptic terminals,presynaptic dopaminergic neurons function toreuptakethe excess dopamine.

Other neurotransmitters

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The putamen also plays a role inmodulationof other neurotransmitters. It releases GABA, enkephalin,substance P,andacetylcholine.It receivesserotoninandglutamate.

Function: motor skills

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The putamen is interconnected with many other structures, and works in conjunction with them to influence many types of motor behaviors. These include motor planning, learning, and execution,[3]motor preparation,[4]specifying amplitudes of movement,[5]and movement sequences.[6]

Some neurologists hypothesize that the putamen also plays a role in the selection of movement (e.g.Tourette syndrome) and the "automatic" performance of previously learned movements (e.g.Parkinson's disease).[7]

In one study it was found that the putamen controls limb movement. The goal of this study was to determine whether particular cell activity in the putamen of primates was related to the direction of limb movement or to the underlying pattern of muscular activity. Two monkeys were trained to perform tasks that involved the movement of loads. The tasks were created so that movement could be distinguished from muscle activity. Neurons in the putamen were selected for monitoring only if they were related both to the task and to arm movements outside the task. It was shown that 50% of the neurons that were monitored were related to the direction of movement, independent of the load.[8]

Another study was done to investigate movement extent and speed usingPETmapping of regional cerebral blood flow in 13 humans. Movement tasks were performed with ajoystick-controlledcursor.Statistical tests were done to calculate the extent of movements and what regions of the brain the movements correlate to. It was found that "increasing movement extent was associated with parallel increases of rCBF in bilateral basal ganglia (BG; putamen and globus pallidus) and ipsilateral cerebellum." This not only shows that the putamen affects movement but it also shows that the putamen integrates with other structures in order to perform tasks.[9]

One study was done in order to specifically investigate how the basal ganglia influences the learning of sequential movements. Two monkeys were trained to press a series of buttons in sequence. The methods used were designed to be able to monitor the well-learned tasks versus the new tasks.Muscimolwas injected into various parts of the basal ganglia, and it was found that "the learning of new sequences became deficient after injections in the anterior caudate and putamen, but not the middle-posterior putamen". This shows that different areas of thestriatumare utilized when performing various aspects of the learning of sequential movements.[10]

Role in learning

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In many studies, it has become apparent that the putamen plays a role in many types of learning. Some examples are listed below:

Reinforcement and implicit learning

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Along with various types of movement, the putamen also affects reinforcement learning andimplicit learning.[11]

Reinforcement learningis interacting with the environment and catering actions to maximize the outcome. Implicit learning is a passive process where people are exposed to information and acquire knowledge through exposure. Although the exact mechanisms are not known, it is clear that dopamine and tonically active neurons play a key role here. Tonically active neurons arecholinergicinterneuronsthat fire during the entire duration of the stimulus and fire at about 0.5–3 impulses per second. Phasic neurons are the opposite and only fire an action potential when movement occurs.[12]

Category learning

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One particular study used patients with focal lesions on the basal ganglia (specifically the putamen) due tostrokein order to studycategory learning.The advantage to using these types of patients is that dopaminergic projections to theprefrontal cortexare more likely to be intact. Also, in these patients, it is easier to relate specific brain structures to function because the lesion only occurs in a specific place. The goal of this study was to determine whether or not these lesions affect rule-based and information-integration task learning. Rule-based tasks are learned via hypothesis-testing dependent on working memory. Information-integration tasks are ones wherein the accuracy is maximized when information from two sources are integrated at a pre-decisional stage, which follows a procedural-based system.

Seven participants with basal ganglialesionswere used in the experiment, along with nine control participants. It is important to note that the caudate was not affected. The participants were tested for each type of learning during separate sessions, so the information processes would not interfere with each other. During each session, participants sat in front of a computer screen and various lines were displayed. These lines were created by using a randomization technique where random samples were taken from one of four categories. For ruled-based testing, these samples were used to construct lines of various length and orientation that fell into these four separate categories. After the stimulus was displayed, the subjects were asked to press 1 of 4 buttons to indicate which category the line fell into. The same process was repeated for information-integration tasks, and the same stimuli were used, except that the category boundaries were rotated 45°. This rotation causes the subject to integrate the quantitative information about the line before determining what category it is in.

It was found that subjects in the experimental group were impaired while performing rule-based tasks, but not information-integration ones. After statistical testing, it was also hypothesized that the brain began using information-integration techniques to solve the rule-based learning tasks. Since rule-based tasks use the hypothesis-testing system of the brain, it can be concluded that the hypothesis-testing system of the brain was damaged/weakened. It is known that the caudate and working memories are part of this system. Therefore, it was confirmed that the putamen is involved in category learning, competition between the systems, feed-back processing in rule-based tasks, and is involved in the processing of pre-frontal regions (which relate to working memory and executive functioning). Now it is known that not only the basal ganglia and caudate affect category learning.[13]

Role in "hate circuit"

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Tentative studies have suggested that the putamen may play a role in the so-called "hatecircuit "of the brain. A recent study was done by the department of cell and developmental biology atUniversity College London.AnfMRIwas carried out on subjects while they viewed a picture of people they hated and people who were "neutral". During the experiment, a "hate score" was recorded for each picture. The activity in subcortical areas of the brain implied that the "hate circuit" involves thesuperior frontal gyrus,the putamen and theinsula.[14]It has been theorized that the "putamen plays a role in the perception ofcontemptanddisgust,and may be part of themotor systemthat's mobilized to take action. "It was also found that the amount of activity in the hate circuit correlates with the amount of hate a person declares, which could have legal implications concerning malicious crimes.[15]

Role in transgender individuals

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The putamen of transgender women was found to have significantly larger amounts of grey matter compared to the putamen of cisgender men. This possibly suggests that a difference in the putamen may exist betweentrans womenand cisgender men.[16]

Pathology

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Parkinson's disease

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After discovering the function of the putamen, it has become apparent to neurologists that the putamen and other parts of the basal ganglia play an important role inParkinson's diseaseand other diseases that involve the degeneration ofneurons.[17]

Parkinson's disease is the slow and steady loss of dopaminergic neurons in substantia nigra pars compacta. In Parkinson's disease the putamen plays a key role because its inputs and outputs are interconnected to the substantia nigra and the globus pallidus. In Parkinson's disease the activity in direct pathways to interior globus pallidus decreases and activity in indirect pathways to external globus pallidus increases. It has also been noted that Parkinson's patients have a difficult time with motor planning.

Other diseases and disorders

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The following diseases and disorders are linked with the putamen:

In other animals

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The putamen in humans is relatively similar in structure and function to other animals. Therefore, many studies on the putamen have been done on animals (monkeys,rats,cats,etc.), as well as humans. However, inter-species variations are indeed observed in mammals, and have been documented for white matter putaminal connectivity. Variation is primarily related to structural connectivity patterns, while somatotopic organization principles are retained. Primate research since the 1980s through to the present has established that cortical regions related to higher-order cognition primarily send afferent neurons to the rostral-most portion of the putamen, while the remainder of this structure in primates primarily serves sensorimotor functions and is densely interconnected with primary and supplementary motor regions.

Additional images

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  • Coronal section of brain throughanterior commissure.
  • Horizontal section of right cerebral hemisphere.
  • Brain
  • Human brain frontal (coronal) section
  • Horizontal slice of MRI-image showing the putamen. The other nuclei of the basal ganglia (caudate nucleus and globus pallidus) can be seen as well.
  • Putamen
  • Putamen
  • Putamen along with other subcortical structures
  • Putamen highlighted in green on coronal T1 MRI images
  • Putamen highlighted in green on sagittal T1 MRI images
  • Putamen highlighted in green on transversal T1 MRI images

See also

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References

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  1. ^"Latin Definitions for: Putare (Latin Search) - Latin Dictionary and Grammar Resources - Latdict".
  2. ^abAlexander GE; Crutcher MD (July 1990). "Functional architecture of basal ganglia circuits: neural substrates of parallel processing".Trends in Neurosciences.13(7): 266–71.doi:10.1016/0166-2236(90)90107-L.PMID1695401.S2CID3990601.
  3. ^DeLong MR; Alexander GE; Georgopoulos AP; Crutcher MD; Mitchell SJ; Richardson RT (1984). "Role of basal ganglia in limb movements".Human Neurobiology.2(4): 235–44.PMID6715208.
  4. ^Alexander GE; Crutcher MD (July 1990). "Preparation for movement: neural representations of intended direction in three motor areas of the monkey".Journal of Neurophysiology.64(1): 133–50.doi:10.1152/jn.1990.64.1.133.PMID2388061.
  5. ^Delong MR; Georgopoulos AP; Crutcher MD; Mitchell SJ; Richardson RT; Alexander GE (1984). "Functional Organization of the Basal Ganglia: Contributions of Single‐Cell Recording Studies".Ciba Foundation Symposium 107 - Functions of the Basal Ganglia.Novartis Foundation Symposia. Vol. 107. pp. 64–82.doi:10.1002/9780470720882.ch5.ISBN9780470720882.PMID6389041.
  6. ^Marchand WR; Lee JN; Thatcher JW; Hsu EW; Rashkin E; Suchy Y; Chelune G; Starr J; Barbera SS (June 11, 2008). "Putamen coactivation during motor task execution".NeuroReport.19(9): 957–960.doi:10.1097/WNR.0b013e328302c873.PMID18521000.S2CID11087809.
  7. ^Griffiths PD; Perry RH; Crossman AR (March 14, 1994). "A detailed anatomical analysis of neurotransmitter receptors in the putamen and caudate in Parkinson's disease and Alzheimer's disease".Neuroscience Letters.169(1–2): 68–72.doi:10.1016/0304-3940(94)90358-1.PMID8047295.S2CID24324548.
  8. ^Crutcher MD; DeLong MR (1984). "Single cell studies of the primate putamen. II. Relations to direction of movement and pattern of muscular activity".Exp. Brain Res.53(2): 244–58.doi:10.1007/bf00238154.PMID6705862.S2CID22320601.
  9. ^Turner RS; Desmurget M; Grethe J; Crutcher MD; Grafton ST (December 2003). "Motor subcircuits mediating the control of movement extent and speed".Journal of Neurophysiology.90(6): 3958–66.doi:10.1152/jn.00323.2003.PMID12954606.S2CID7012970.
  10. ^Miyachi S; Hikosaka O; Miyashita K; Kárádi Z; Rand MK (June 1997). "Differential roles of monkey striatum in learning of sequential hand movement".Exp. Brain Res.115(1): 1–5.doi:10.1007/PL00005669.PMID9224828.S2CID13541431.
  11. ^Packard MG; Knowlton BJ (2002). "Learning and memory functions of the Basal Ganglia".Annu Rev Neurosci.25(1): 563–93.doi:10.1146/annurev.neuro.25.112701.142937.PMID12052921.
  12. ^Yamada H; Matsumoto N; Kimura M (April 7, 2004)."Tonically active neurons in the primate caudate nucleus and putamen differentially encode instructed motivational outcomes of action".Journal of Neuroscience.24(14): 3500–10.doi:10.1523/JNEUROSCI.0068-04.2004.PMC6729748.PMID15071097.
  13. ^Ell SW; Marchant NL; Ivry RB (2006)."Focal putamen lesions impair learning in rule-based, but not information-integration categorization tasks".Neuropsychologia.44(10): 1737–51.doi:10.1016/j.neuropsychologia.2006.03.018.PMID16635498.S2CID16312162.
  14. ^Tao, H.; Guo, S.; Ge, T.; Kendrick, K. M.; Xue, Z.; Liu, Z.; Feng, J. (January 2013)."Depression uncouples brain hate circuit".Molecular Psychiatry.18(1): 101–111.doi:10.1038/mp.2011.127.PMC3526729.
  15. ^Zeki S; Romaya JP (2008). Lauwereyns, Jan (ed.)."Neural Correlates of Hate".PLOS ONE.3(10): e3556.Bibcode:2008PLoSO...3.3556Z.doi:10.1371/journal.pone.0003556.PMC2569212.PMID18958169.
  16. ^Luders E; Sánchez FJ; Gaser C; et al. (July 2009)."Regional gray matter variation in male-to-female transsexualism".NeuroImage.46(4): 904–7.doi:10.1016/j.neuroimage.2009.03.048.PMC2754583.PMID19341803.
  17. ^DeLong MR; Wichmann T (January 2007). "Circuits and circuit disorders of the basal ganglia".Arch. Neurol.64(1): 20–4.doi:10.1001/archneur.64.1.20.PMID17210805.
  18. ^de Jong LW; van der Hiele K; Veer IM; Houwing JJ; Westendorp RG; Bollen EL; de Bruin PW; Middelkoop HA; van Buchem MA; van der Grond J (December 2008)."Strongly reduced volumes of putamen and thalamus in Alzheimer's disease: an MRI study".Brain.131(12): 3277–85.doi:10.1093/brain/awn278.PMC2639208.PMID19022861.
  19. ^Martin H. Teicher; Carl M. Anderson; Ann Polcari; Carol A. Glod; Luis C. Maas; Perry F. Renshaw (2000). "Functional deficits in basal ganglia of children with attention-deficit/hyperactivity disorder shown with functional magnetic resonance imaging relaxometry".Nature Medicine.6(12): 470–3.doi:10.1038/74737.PMID10742158.S2CID32093789.
  20. ^Radua, Joaquim; Mataix-Cols, David (November 2009)."Voxel-wise meta-analysis of grey matter changes in obsessive–compulsive disorder".British Journal of Psychiatry.195(5): 393–402.doi:10.1192/bjp.bp.108.055046.PMID19880927.
  21. ^abRadua, Joaquim; van den Heuvel, Odile A.; Surguladze, Simon; Mataix-Cols, David (5 July 2010). "Meta-analytical comparison of voxel-based morphometry studies in obsessive-compulsive disorder vs other anxiety disorders".Archives of General Psychiatry.67(7): 701–711.doi:10.1001/archgenpsychiatry.2010.70.PMID20603451.
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