WordNet

grow out of, have roots in, originate in; "The increase in the national debt stems from the last war"
stop the flow of a liquid; "staunch the blood flow"; "stem the tide" (同)stanch, staunch, halt
remove the stem from; "for automatic natural language processing, the words must be stemmed"
the tube of a tobacco pipe
cause to point inward; "stem your skis"
natural process that causes something to form; "the formation of gas in the intestine"; "the formation of crystals"; "the formation of pseudopods"
the act of fabricating something in a particular shape (同)shaping
a particular spatial arrangement
creation by mental activity; "the formation of sentences"; "the formation of memories"
an arrangement of people or things acting as a unit; "a defensive formation"; "a formation of planes"
kill by smashing someones skull
mental ability; "hes got plenty of brains but no common sense" (同)brainpower, learning_ability, mental capacity, mentality, wit
that part of the central nervous system that includes all the higher nervous centers; enclosed within the skull; continuous with the spinal cord (同)encephalon
the brain of certain animals used as meat
hit on the head

PrepTutorEJDIC

(草の)『茎』,(木の)『幹』 / 葉柄,花梗(かこう) / 『茎状のもの』;(杯・グラスの)『脚』,(パイプ・さじの)柄,(時計の)りゅうず / (単語の)語幹,語根 / 船首;船首材 / …‘の'茎(軸)を取り去る,へたをとる / (…から)生じる,(…に)由来する《+『from』+『名』(do『ing』)》
〈流れなど〉‘を'止める / 〈風・水流など〉‘に'逆らって進む,抵抗する / 〈攻撃・反対など〉‘を'くい止める,押さえる
〈U〉(…の)『形成』,構成,育成《+『of』+『名』》 / 〈C〉形成されたもの,構成物;(その)構造,組織 / 〈U〉〈C〉隊形,陣形
《所有・所属》…『の』,…のものである,…に属する・《材料・要素》…『でできた』,から成る・《部分》…『の』[『中の』] ・《数量・単位・種類を表す名詞に付いて》…の・《原因・動機》…『で』,のために(because of) ・《主格関係》…『の』,による,によって・《目的格関係》…『を』,の・《同格関係》…『という』・《関係・関連》…『についての』[『の』],の点で・《抽象名詞などと共に》…の[性質をもつ] ・《『It is』+『形』+『of』+『名』+『to』 doの形で,ofの後の名詞を意味上の主語として》・《分離》…『から』・《起原・出所》…『から』[『の』](out of) ・《『名』+『of』+『a』(『an』)+『名』の形で》…のような・《『名』+『of』+『mine』(『yours, his』など独立所有格)の形で》…の…・《時》(1)《副詞句を作って》…に《形容詞句を作って》…の・《時刻》《米》…前(to,《米》before)
『脳』,脳髄 / 《しばしば複数形で》『頭脳』,『知力』 / 《話》秀才,知的指導者 / …‘の'頭を打ち砕く

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/08 20:51:49」(JST)

wiki en

The reticular formation (lat. formatio reticularis) is a set of interconnected nuclei that are located throughout the brainstem. The reticular formation is not anatomically well defined because it includes neurons located in diverse parts of the brain. The neurons of the reticular formation all play a crucial role in maintaining behavioral arousal and consciousness. The functions of the reticular formation are modulatory and premotor. The modulatory functions are primarily found in the rostral sector of the reticular formation and the premotor functions are localized in the neurons in more caudal regions.

The reticular formation is divided into three columns: raphe nuclei (median), magnocellular red nucleus (medial zone), and parvocellular reticular nucleus (lateral zone). The raphe nuclei is the place of synthesis of the neurotransmitter serotonin, which plays an important role in mood regulation. The magnocellular red nucleus is involved in motor coordination. The parvocellular nucleus regulates exhalation.^[1]

It is essential for governing some of the basic functions of higher organisms, and is one of the phylogenetically oldest portions of the brain.

Structure

A cross section of the lower part of the pons showing the pontine reticular formation labeled as #9

The reticular formation has been functionally cleaved both sagittally and coronally.

Traditionally the nuclei are divided into three columns

In the median column – the raphe nuclei
In the medial column – magnocellular nuclei (because of larger size of the cells)
In the lateral column – parvocellular nuclei (because of smaller size of the cells)

The original functional differentiation was a division of caudal and rostral, this was based upon the observation that the lesioning of the rostral reticular formation induces a hypersomnia in the cat brain. In contrast, lesioning of the more caudal portion of the reticular formation produces insomnia in cats. This study has led to the idea that the caudal portion inhibits the rostral portion of the reticular formation.

Sagittal division reveals more morphological distinctions. The raphe nuclei form a ridge in the middle of the reticular formation, and, directly to its periphery, there is a division called the medial reticular formation. The medial RF is large and has long ascending and descending fibers, and is surrounded by the lateral reticular formation. The lateral RF is close to the motor nuclei of the cranial nerves, and mostly mediates their function.

Medial and lateral reticular formation

The medial reticular formation and lateral reticular formation are two columns of neuronal nuclei with ill-defined boundaries that send projections through the medulla and into the mesencephalon (midbrain). The nuclei can be differentiated by function, cell type, and projections of efferent or afferent nerves.

Function

The reticular formation consists of more than 100 small neural networks, with varied functions including the following:

Somatic motor control – Some motor neurons send their axons to the reticular formation nuclei, giving rise to the reticulospinal tracts of the spinal cord. These tracts function in maintaining tone, balance, and posture—especially during body movements. The reticular formation also relays eye and ear signals to the cerebellum so that the cerebellum can integrate visual, auditory, and vestibular stimuli in motor coordination. Other motor nuclei include gaze centers, which enable the eyes to track and fixate objects, and central pattern generators, which produce rhythmic signals to the muscles of breathing and swallowing.
Cardiovascular control – The reticular formation includes the cardiac and vasomotor centers of the medulla oblongata.
Pain modulation – The reticular formation is one means by which pain signals from the lower body reach the cerebral cortex. It is also the origin of the descending analgesic pathways. The nerve fibers in these pathways act in the spinal cord to block the transmission of some pain signals to the brain.
Sleep and consciousness – The reticular formation has projections to the thalamus and cerebral cortex that allow it to exert some control over which sensory signals reach the cerebrum and come to our conscious attention. It plays a central role in states of consciousness like alertness and sleep. Injury to the reticular formation can result in irreversible coma.
Habituation – This is a process in which the brain learns to ignore repetitive, meaningless stimuli while remaining sensitive to others. A good example of this is when a person can sleep through loud traffic in a large city, but is awakened promptly due to the sound of an alarm or crying baby. Reticular formation nuclei that modulate activity of the cerebral cortex are part of the reticular activating system.^[2]^[3]

Clinical significance

Mass lesions in the brainstem cause severe alterations in level of consciousness (such as coma) because of their effects on the reticular formation.^[4] Bilateral damage to the reticular formation of the midbrain may lead to coma or death.^[5]

Lesions in the reticular formation have been found in the brains of people who have post-polio syndrome, and some imaging studies have shown abnormal activity in this area in people with chronic fatigue syndrome, indicating a high likelihood that damage to the reticular formation is responsible for the fatigue associated with these syndromes.

History

The term "reticular formation" was coined in the late 19th century, coinciding with Ramon y Cajal’s neuron doctrine. Allan Hobson states in his book The Reticular Formation Revisited that the name is an etymological vestige from the fallen era of the aggregate field theory in the neural sciences. The term "reticulum" means "netlike structure," which is what the reticular formation resembles at first glance. It has been described as being either too complex to study or an undifferentiated part of the brain with no organization at all. Eric Kandel describes the reticular formation as being organized in a similar manner to the intermediate gray matter of the spinal cord. This chaotic, loose, and intricate form of organization is what has turned off many researchers from looking farther into this particular area of the brain^{[citation needed]}. The cells lack clear ganglionic boundaries, but do have clear functional organizations and distinct cell types.

The term "reticular formation" is seldom used anymore except to speak in generalities. Modern scientists usually refer to the individual nuclei that comprise the reticular formation.

References

^ http://thebrain.mcgill.ca/flash/a/a_11/a_11_cr/a_11_cr_cyc/a_11_cr_cyc.html
^ http://biology.about.com/library/organs/brain/blreticular.htm
^ Saladin, Kenneth S. Anatomy & Physiology the Unity of Form and Function. Dubuque: McGraw-Hill, 2009. Print.
^ Tindall SC (1990). "Level of consciousness". In Walker HK, Hall WD, Hurst JW. Clinical Methods: The History, Physical, and Laboratory Examinations. Butterworth Publishers. Retrieved 2008-07-04.
^ The Human Brain: An Introduction to its Functional Anatomy 5th ed by J Nolte chpt 11 pp. 262–290

Additional images

Deep dissection of brain-stem. Ventral view.
The formatio reticularis of the medulla oblongata, shown by a transverse section passing through the middle of the olive.

External links

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English Journal

High-resolution anatomy of the human brain stem using 7-T MRI: improved detection of inner structures and nerves?

Gizewski ER1, Maderwald S, Linn J, Dassinger B, Bochmann K, Forsting M, Ladd ME.Author information 1Department of Neuroradiology, Medical University Innsbruck, Anichstr. 35, A-6020, Innsbruck, Austria, elke.gizewski@i-med.ac.at.AbstractINTRODUCTION: The purpose of this paper is to assess the value of 7 Tesla (7 T) MRI for the depiction of brain stem and cranial nerve (CN) anatomy.
Neuroradiology.Neuroradiology.2014 Mar;56(3):177-86. doi: 10.1007/s00234-013-1312-0. Epub 2013 Dec 20.
INTRODUCTION: The purpose of this paper is to assess the value of 7 Tesla (7 T) MRI for the depiction of brain stem and cranial nerve (CN) anatomy.METHODS: Six volunteers were examined at 7 T using high-resolution SWI, MPRAGE, MP2RAGE, 3D SPACE T2, T2, and PD images to establish scanning paramete
PMID 24357075

Intraspinal transplantation and modulation of donor neuron electrophysiological activity.

Lee KZ1, Lane MA2, Dougherty BJ1, Mercier LM3, Sandhu MS1, Sanchez JC2, Reier PJ3, Fuller DD4.Author information 1Dept. Physical Therapy, College of Public Health and Health Professions, McKnight Brain Institute, University of Florida, USA.2Dept. of Biomedical Engineering, College of Engineering, University of Miami, USA.3Dept. Neuroscience, College of Medicine, McKnight Brain Institute, University of Florida, USA.4Dept. Physical Therapy, College of Public Health and Health Professions, McKnight Brain Institute, University of Florida, USA. Electronic address: ddf@phhp.ufl.edu.AbstractRat fetal spinal cord (FSC) tissue, naturally enriched with interneuronal progenitors, was introduced into high cervical, hemi-resection (Hx) lesions. Electrophysiological analyses were conducted to determine if such grafts exhibit physiologically-patterned neuronal activity and if stimuli which increase respiratory motor output also alter donor neuron bursting. Three months following transplantation, the bursting activity of FSC neurons and the contralateral phrenic nerve were recorded in anesthetized rats during a normoxic baseline period and brief respiratory challenges. Spontaneous neuronal activity was detected in 80% of the FSC transplants, and autocorrelation of action potential spikes revealed distinct correlogram peaks in 87% of neurons. At baseline, the average discharge frequency of graft neurons was 13.0 ± 1.7 Hz, and discharge frequency increased during a hypoxic respiratory challenge (p<0.001). Parallel studies in unanesthetized rats showed that FSC tissue recipients had larger inspiratory tidal volumes during brief hypoxic exposures (p<0.05 vs. C2Hx rats). Anatomical connectivity was explored in additional graft recipients by injecting a transsynaptic retrograde viral tracer (pseudorabies virus, PRV) directly into matured transplants. Neuronal labeling occurred throughout graft tissues and also in the host spinal cord and brainstem nuclei, including those associated with respiratory control. These results underscore the neuroplastic potential of host-graft interactions and training approaches to enhance functional integration within targeted spinal circuitry.
Experimental neurology.Exp Neurol.2014 Jan;251:47-57. doi: 10.1016/j.expneurol.2013.10.016. Epub 2013 Nov 2.
Rat fetal spinal cord (FSC) tissue, naturally enriched with interneuronal progenitors, was introduced into high cervical, hemi-resection (Hx) lesions. Electrophysiological analyses were conducted to determine if such grafts exhibit physiologically-patterned neuronal activity and if stimuli which inc
PMID 24192152

Dual effects of 5-HT(1a) receptor activation on breathing in neonatal mice.

Corcoran AE1, Commons KG, Wu Y, Smith JC, Harris MB, Richerson GB.Author information 1Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, Alaska 99775, Departments of Neurology and Cellular and Molecular Physiology, Yale University, New Haven, Connecticut 06520, Department of Physiology and Neurobiology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire 03756, Department of Anesthesia, Perioperative and Pain Medicine, Boston Children's Hospital, Boston, Massachusetts 02115, Cellular and Systems Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, Veteran's Affairs Medical Center, Iowa City, Iowa 52242, and Departments of Neurology, and Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa 52242.AbstractInhibitory 5-HT(1a) receptors are located on serotonin (5-HT) neurons (autoreceptors) as well as neurons of the respiratory network (heteroreceptors). Thus, effects on breathing of 5-HT(1a) agonists, such as (R)-(+)-8-hydroxy-2-(di-N-propylamino) tetralin (8-OH-DPAT), could either be due to decreased firing of 5-HT neurons or direct effects on the respiratory network. Mice in which the transcription factor LMX1B is genetically deleted selectively in Pet1-1-expressing cells (Lmx1b(f/f/p)) essentially have complete absence of central 5-HT neurons, providing a unique opportunity to separate the effect of activation of downstream 5-HT(1a) heteroreceptors from that of autoreceptors. We used rhythmically active medullary slices from wild-type (WT) and Lmx1b(f/f/p) neonatal mice to differentiate autoreceptor versus heteroreceptor effects of 8-OH-DPAT on hypoglossal nerve respiratory output. 8-OH-DPAT transiently increased respiratory burst frequency in Lmx1b(f/f/p) preparations, but not in WT slices. This excitation was abolished when synaptic inhibition was blocked by GABAergic/glycinergic receptor antagonists. Conversely, after 10 min of application, frequency in Lmx1b(f/f/p) slices was not different from baseline, whereas it was significantly depressed in WT slices. In WT mice in vivo, subcutaneous injection of 8-OH-DPAT produced similar biphasic respiratory effects as in Lmx1b(f/f/p) mice. We conclude that 5-HT1a receptor agonists have two competing effects: rapid stimulation of breathing due to excitation of the respiratory network, and delayed inhibition of breathing due to autoreceptor inhibition of 5-HT neurons. The former effect is presumably due to inhibition of inhibitory interneurons embedded in the respiratory network.
The Journal of neuroscience : the official journal of the Society for Neuroscience.J Neurosci.2014 Jan 1;34(1):51-9. doi: 10.1523/JNEUROSCI.0864-13.2014.
Inhibitory 5-HT(1a) receptors are located on serotonin (5-HT) neurons (autoreceptors) as well as neurons of the respiratory network (heteroreceptors). Thus, effects on breathing of 5-HT(1a) agonists, such as (R)-(+)-8-hydroxy-2-(di-N-propylamino) tetralin (8-OH-DPAT), could either be due to decrease
PMID 24381267

Japanese Journal

橋，延髄海綿状血管腫5例の直達手術

玉置智規,野手洋治,寺本明
脳卒中の外科 40(3), 154-158, 2012
… We reviewed five surgical cases of brain stem cavernous angioma. … The outcome of surgery was good or fair in all patients. … Postoperative facial nerve and paramedian pontine reticular formation dysfunction occurred in one patient. …
NAID 130004479821

ストレスからみたトラウマ (特集トラウマ概念の再考/現在におけるトラウマ概念)

杉晴夫
トラウマティック・ストレス : 日本トラウマティック・ストレス学会誌 7(2), 120-126, 2009
NAID 40019131541

橋下部腹側海綿状血管腫の摘出術 : 手術アプローチと脳幹進入部について

佐々木雄彦,早瀬一幸,佐藤憲市,渡部寿一,瀬尾善宣,伊東民雄,中川原譲二,中村博彦
脳卒中の外科 36(2), 112-117, 2008-03-31
… We report 2 patients whose lower ventral pontine cavernous angiomas were removed via the ventral lower pons lateral to the abducens nerve where the angiomas are closest to the surface of the brain stem. … A suboccipital transcondylar approach (STC) provided a sufficient operative field to remove the angiomas from the lower pons lateral to the abducens nerve and an adequate operative trajectory along the longitudinal axis of the angiomas. …
NAID 110006657126

「脳幹網様体」

reticular formation
	Axial section of the pons, at its upper part. (Formatio reticularis labeled at left.)
	Section of the medulla oblongata at about the middle of the olive. (Formatio reticularis grisea and formatio reticularis alba labeled at left.)
Details
Latin	formatio reticularis
Identifiers
Gray's	p.784
MeSH	A08.186.211.132.772
NeuroNames	ancil-225
NeuroLex ID	Reticular formation
Dorlands; /Elsevier	f_13/12374790
TA	A14.1.00.021; A14.1.05.403; A14.1.06.327
FMA	77719
	Anatomical terms of neuroanatomy

　　[★]

英: brainstem reticular formation (KL), reticular formation of brain stem
ラ: formatio reticularis truncus cerebri
関: 網様体、脳幹

脳幹網様体

被蓋の大部分を占める。
中脳、橋、延髄の内側部に存在。
上行性網様体賦活系として機能する。
様々な方向に走行する神経線維の間に個々の神経細胞体や神経核が散在する構造
吻側は視床の髄板内核。尾側は脊髄の中間帯に移行。

脳幹網様体の分類

入出力

(KL.708)

	入力	出力
	求心性線維	遠心性線維
大脳皮質	○	網様体視床路経由
小脳	○	網様体小脳路
中脳	上丘・赤核	中脳核
脊髄	脊髄網様体路　脊髄視床路	網様体脊髄路