WordNet

make a score (on a hole) equal to par
(golf) the standard number of strokes set for each hole on a golf course, or for the entire course; "a par-5 hole"; "par for this course is 72"
a thin fragment or slice (especially of wood) that has been shaved from something (同)sliver, shaving
(usually plural) a part of a fruit or vegetable that is pared or cut off; especially the skin or peel; "she could peel an apple with a single long paring"

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〈U〉同等,同価,同水準,同程度 / (また『par value』)〈U〉平価,額面価格 / 〈U〉(程度・質・状態・数量などの)平均,標準;(精神・健康などの)常態 / 〈C〉(ゴルフで)標準打数,パー / 《名詞の前にのみ用いて》平均の,標準の / 額面の
(ゴルフで)〈1ホールまたは1コース〉‘を'基準打数でとる,パーで上がる
〈U〉(皮を)むくこと,削ること / 〈C〉《複数形で》むいた皮,削りくず
とうちゃん(papa)

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/08/10 10:07:12」(JST)

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The pars reticulata is a portion of the substantia nigra.

Anatomy

Neurons in the pars reticulata are much less densely packed than those in the pars compacta (they were sometimes named pars diffusa). They are smaller and thinner than the dopaminergic neurons and conversely identical and morphologically similar to the pallidal neurons (see primate basal ganglia). Their dendrites as well as the pallidal are preferentially perpendicular to the striatal afferents.^[1] The massive striatal afferences corresponds to the medial end of the striato-pallidonigral bundle. Nigral neurons have the same peculiar synaptology with the striatal axonal endings. They make connections with the dopamine neurons of the pars compacta whose long dendrites plunge deeply in the pars reticulata. The neurons of the pars reticulata and pars lateralis produce the neurotransmitter gamma-aminobutyric acid (GABA). The neurons of the pars reticulata through the nigrothalamic bundle send axons to a particular part of the motor thalamus. The nigral territory corresponds to the nucleus ventralis anterior (VA) (see also List of thalamic nuclei) (different from the pallidal VO). VA is the origin of one output of the basal ganglia system. It sends axons to the frontal and oculomotor cortex. In addition the pars reticulata sends neurons to the pars parafascicularis of the central region of the thalamus and to the pedunculopontine complex). The particularity of the pars lateralis is to send its axons to the superior colliculus,^[2] which is a too minimized output of the basal ganglia system.

Function

The neurons of the pars reticulata are fast-spiking pacemakers, generating action potentials in the absence of synaptic input.^[3] In primates they discharge at a mean rate of 68Hz in contrast to dopaminergic neurons (below 8Hz).^[4] They receive abundant afferrences from the striatum (mainly from the associative striatum) with the same very peculiar synaptology as the pallidum. It receives axons from the subthalamic nucleus and a dopaminergic innervation from the dopaminergic ensemble.

The pars reticulata is one of the two primary output nuclei of the basal ganglia system to the motor thalamus (the other output is the internal segment of the globus pallidus).The nigral neurons have their own territory distinct from the cerebellar and the pallidal in the nucleus ventralis anterior VA. This sends axons to the frontal and oculomotor cortex. Hikosaka and Wurtz^[5]^[6]^[7]^[8] devoted four papers to "the visual and oculomotor functions of the monkey substantia nigra pars reticulata". This is largely involved in orientation and the control of eye movements in stabilisation of gaze and in saccades.

Pathology

The function of the neurons of the pars compacta (not reticulata) is profoundly changed (60% of Dopamine secreting neurons, 80% decrease in dopamine in striatum) in parkinsonism and epilepsy. These changes are thought to be mostly secondary to pathology elsewhere in the brain, but may be crucial to understanding the generation of the symptoms of these disorders.

References

^ François, C.; Yelnik, J. & Percheron, G. (1987). "Golgi study of the primate substantia nigra. II. Spatial organization of dendritic arborizations in relation to the cytoarchitectonic boundaries and to the striatonigral bundle". Journal of Comparative Neurology 265 (4): 473–493. doi:10.1002/cne.902650403. PMID 3123530.
^ François, C.; Percheron, G. & Yelnik, J. (1984). "Localization of nigrostriatal, nigrothalamic and nigrotectal neurons in ventricular coordinates in macaques". Neuroscience 13 (1): 61–76. doi:10.1016/0306-4522(84)90259-8. PMID 6387531.
^ Atherton, J.F. & Bevan, M.D. (2005). "Ionic mechanisms underlying autonomous action potential generation in the somata and dendrites of GABAergic substantia nigra pars reticulata neurons in vitro". Journal of Neuroscience 25 (36): 8272–8281. doi:10.1523/JNEUROSCI.1475-05.2005. PMID 16148235.
^ Schultz, W. (1986). "Activity of pars reticulata neurons of monkey substantia nigra in relation to motor, sensory and complex events". Journal of Neurophysiology 55 (4): 660–677. PMID 3701399.
^ Hikosaka, O; Wurtz, RH (1983). "Visual and oculomotor functions of monkey substantia nigra pars reticulata. I. Relation of visual and auditory responses to saccades.". Journal of neurophysiology 49 (5): 1230–53. PMID 6864248.
^ Hikosaka, O; Wurtz, RH (1983). "Visual and oculomotor functions of monkey substantia nigra pars reticulata. II. Visual responses related to fixation of gaze.". Journal of neurophysiology 49 (5): 1254–67. PMID 6864249.
^ Hikosaka, O; Wurtz, RH (1983). "Visual and oculomotor functions of monkey substantia nigra pars reticulata. III. Memory-contingent visual and saccade responses.". Journal of neurophysiology 49 (5): 1268–84. PMID 6864250.
^ Hikosaka, O; Wurtz, RH (1983). "Visual and oculomotor functions of monkey substantia nigra pars reticulata. IV. Relation of substantia nigra to superior colliculus.". Journal of neurophysiology 49 (5): 1285–301. PMID 6306173.

UpToDate Contents

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1. パーキンソン病の病因および発症機序 etiology and pathogenesis of parkinson disease
2. 小児における運動減少性運動障害 bradykinetic movement disorders in children
3. 原発性眼障害関連の網膜血管炎 retinal vasculitis associated with primary ocular disorders
4. 大脳皮質基底核変性症 corticobasal degeneration
5. 小児における運動過多な運動障害 hyperkinetic movement disorders in children

English Journal

MR Imaging of the Substantia Nigra at 7 T Enables Diagnosis of Parkinson Disease.

Cosottini M1, Frosini D, Pesaresi I, Costagli M, Biagi L, Ceravolo R, Bonuccelli U, Tosetti M.Author information 1From the IMAGO7 Foundation, Pisa, Italy (M. Cosottini, M. Costagli); Department of Translational Research and New Surgical and Medical Technologies (M. Cosottini) and Neurology Unit, Department of Clinical and Experimental Medicine (D.F., R.C., U.B.), University of Pisa, Pisa, Italy; Neuroradiology Unit, Department of Diagnostic and Interventional Radiology, Azienda Ospedaliero-Universitaria Pisana (AOUP), Pisa, Italy (I.P.); and Stella Maris Scientific Institute, Pisa, Italy (L.B., M.T.).AbstractPurpose To evaluate the anatomy of the substantia nigra (SN) in healthy subjects by performing 7-T magnetic resonance (MR) imaging of the SN, and to prospectively define the accuracy of 7-T MR imaging in distinguishing Parkinson disease (PD) patients from healthy subjects on an individual basis. Materials and Methods The 7-T MR imaging protocol was approved by the Italian Ministry of Health and by the local competent ethics committee. SN anatomy was described ex vivo on a gross brain specimen by using highly resolved proton-density (spin-echo proton density) and gradient-recalled-echo (GRE) images, and in vivo in eight healthy subjects (mean age, 40.1 years) by using GRE three-dimensional multiecho susceptibility-weighted images. After training on appearance of SN in eight healthy subjects, the SN anatomy was evaluated twice by two blinded observers in 13 healthy subjects (mean age, 54.7 years) and in 17 PD patients (mean age, 56.9 years). Deviations from normal SN appearance were described and indicated as abnormal, and both diagnostic accuracy and intra- and interobserver agreement for diagnosis of PD with 7-T MR imaging were calculated. Results Three-dimensional multiecho susceptibility-weighted 7-T MR imaging reveals a three-layered organization of the SN allowing readers to distinguish pars compacta ventralis and dorsalis from pars reticulata. The abnormal architecture of the SN allowed a discrimination between PD patients and healthy subjects with sensitivity and specificity of 100% and 96.2% (range, 92.3%-100%), respectively. Intraobserver agreement (κ = 1) and interobserver agreement (κ = 0.932) were excellent. Conclusion MR imaging at 7-T allows a precise characterization of the SN and visualization of its inner organization. Three-dimensional multiecho susceptibility-weighted images can be used to accurately differentiate healthy subjects from PD patients, which provides a novel diagnostic opportunity. © RSNA, 2014.
Radiology.Radiology.2014 Feb 26:131448. [Epub ahead of print]
Purpose To evaluate the anatomy of the substantia nigra (SN) in healthy subjects by performing 7-T magnetic resonance (MR) imaging of the SN, and to prospectively define the accuracy of 7-T MR imaging in distinguishing Parkinson disease (PD) patients from healthy subjects on an individual basis. Mat
PMID 24601752

Deep Brain Stimulation of the Subthalamic Nucleus Reestablishes Neuronal Information Transmission in the 6-OHDA Rat Model of Parkinsonism.

Dorval AD 2nd1, Grill WM.Author information 1University of Utah.AbstractPathophysiological activity of basal ganglia neurons accompanies the motor symptoms of Parkinson's disease. High frequency (>90 Hz) deep brain stimulation (DBS) reduces parkinsonian symptoms, but the mechanisms remain unclear. We hypothesize that parkinsonism-associated electrophysiological changes constitute an increase in neuronal firing pattern disorder and a concomitant decrease in information transmission through the ventral basal ganglia; and that effective DBS alleviates symptoms by decreasing neuronal disorder while simultaneously increasing information transfer through the same regions. We tested these hypotheses in the freely behaving, 6-hydroxydopamine-lesioned rat model of hemiparkinsonism. Following the onset of parkinsonism, mean neuronal firing rates were unchanged in spite of a significant increase in firing pattern disorder (i.e., neuronal entropy), in both the globus pallidus and substantia nigra pars reticulata. This increase in neuronal entropy was reversed by symptom-alleviating DBS. While increases in signal entropy are most commonly indicative of similar increases in information transmission, directed information through both regions was substantially reduced (>70%) following the onset of parkinsonism. Again, this decrease in information transmission was partially reversed by DBS. Together, these results suggest that the parkinsonian basal ganglia are rife with entropic activity, and incapable of functional information transmission. Further, they indicate that symptom-alleviating DBS works by lowering the entropic noise floor, enabling more information-rich signal propagation. In this view, the symptoms of parkinsonism may be more a default mode, normally overridden by healthy basal ganglia information. When that information is abolished by parkinsonian pathophysiology, hypokinetic symptoms emerge.
Journal of neurophysiology.J Neurophysiol.2014 Feb 19. [Epub ahead of print]
Pathophysiological activity of basal ganglia neurons accompanies the motor symptoms of Parkinson's disease. High frequency (>90 Hz) deep brain stimulation (DBS) reduces parkinsonian symptoms, but the mechanisms remain unclear. We hypothesize that parkinsonism-associated electrophysiological chang
PMID 24554786

Stimulation of the substantia nigra influences the specification of memory-guided saccades.

Mahamed S1, Garrison TJ, Shires J, Basso MA.Author information 1Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin;AbstractIn the absence of sensory information, we rely on past experience or memories to guide our actions. Because previous experimental and clinical reports implicate basal ganglia nuclei in the generation of movement in the absence of sensory stimuli, we ask here whether one output nucleus of the basal ganglia, the substantia nigra pars reticulata (nigra), influences the specification of an eye movement in the absence of sensory information to guide the movement. We manipulated the level of activity of neurons in the nigra by introducing electrical stimulation to the nigra at different time intervals while monkeys made saccades to different locations in two conditions: one in which the target location remained visible and a second in which the target location appeared only briefly, requiring information stored in memory to specify the movement. Electrical manipulation of the nigra occurring during the delay period of the task, when information about the target was maintained in memory, altered the direction and the occurrence of subsequent saccades. Stimulation during other intervals of the memory task or during the delay period of the visually guided saccade task had less effect on eye movements. On stimulated trials, and only when the visual stimulus was absent, monkeys occasionally (∼20% of the time) failed to make saccades. When monkeys made saccades in the absence of a visual stimulus, stimulation of the nigra resulted in a rotation of the endpoints ipsilaterally (∼2°) and increased the reaction time of contralaterally directed saccades. When the visual stimulus was present, stimulation of the nigra resulted in no significant rotation and decreased the reaction time of contralaterally directed saccades slightly. Based on these measurements, stimulation during the delay period of the memory-guided saccade task influenced the metrics of saccades much more than did stimulation during the same period of the visually guided saccade task. Because these effects occurred with manipulation of nigral activity well before the initiation of saccades and in trials in which the visual stimulus was absent, we conclude that information from the basal ganglia influences the specification of an action as it is evolving primarily during performance of memory-guided saccades. When visual information is available to guide the specification of the saccade, as occurs during visually guided saccades, basal ganglia information is less influential.
Journal of neurophysiology.J Neurophysiol.2014 Feb;111(4):804-16. doi: 10.1152/jn.00002.2013. Epub 2013 Nov 20.
In the absence of sensory information, we rely on past experience or memories to guide our actions. Because previous experimental and clinical reports implicate basal ganglia nuclei in the generation of movement in the absence of sensory stimuli, we ask here whether one output nucleus of the basal g
PMID 24259551

Japanese Journal

REAL TIME SINGLE-CELL RT-PCR ANALYSIS ON DOPAMINE RECEPTOR MRNA EXPRESSION IN SUBSTANTIA NIGRA PARS RETICULATA (Sleep-wakefulness and feeding behavior : From genes to behavior : The 12th Meeting Hirosaki International Forum of Medical Science Communication Center of Hirosaki University School of Medicine October 29, 2010, Hirosaki, Japan)

Nagatomo Katsuhiro,Suga Sechiko,Shibasaki Koji [他]
弘前医学 63(Suppl.), S49-52, 2012
NAID 40020252424

サッカード眼球運動系の神経応答を再現する数理モデル(視聴覚技術,ヒューマンインタフェース)

山下輝彦,小濱剛,神山斉己
映像情報メディア学会技術報告 35(16), 23-26, 2011-03-08
本研究ではサッカード眼球運動の発生メカニズムを解明することを目的として,前頭眼野から脳幹網様体に至る神経細胞ネットワークの数理モデル化を行った.神経生理学知見に基づけば,サッカード発生の際には,まず前頭眼野でサッカード計画が生成され,黒質網様部を介して中脳の上丘に達し,サッカード命令に変換される.上丘では,視線の移動量と移動速度に関する信号に符号化して出力され,これが脳幹網様体に伝達されて眼筋の収 …
NAID 110008609573

Preconditioning with subneurotoxic allyl nitrile: Protection against allyl nitrile neurotoxicity

Tanii Hideji,Higashi T.,Saijoh Kiyofumi
Food and Chemical Toxicology 48(2), 750-754, 2010-02
… Compared with the 0 μmol/kg/day group, animals in the 200 and 400 μmol/kg/day pre-treatment groups exhibited decreased behavioral abnormalities and elevated GABA-positive cell counts in the substantia nigra pars reticulata and the interpeduncular nucleus. …
NAID 120001828362