Habenular nuclei

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Habenular nuclei

?

Mesal aspect of a brain sectioned in the median sagittal plane. The habenular nuclei are not labeled directly, but after expanding, look to region with 'habenular commissure', 'pineal body', and 'posterior commissure'

Details

Identifiers

Latin

nucleus habenularis lateralis, nucleus habenularis medialis

NeuroNames

295

TA

A14.1.08.504

Anatomical terms of neuroanatomy

[edit on Wikidata]

The?habenular nuclei?(habenula?is Latin for "little?rein") acts as a regulator of key?central nervous system?neurotransmitters, connecting the?forebrain?and?midbrain?within the?epithalamus.[1][2][3]?Although it was predominantly studied for its demonstration of asymmetrical brain development and function, in recent years many scientists have begun to examine the habenular nuclei's role in motivation and behavior as it relates to an understanding of the physiology of addiction.

Contents

·?1Anatomy and connectivity

·?2Motivation and addiction

·?2.1Nicotine and nAChRs

·?3References

·?4External links

Anatomy and connectivity[edit]

The habenular nuclei comprise a small group of?nuclei?that are part of the?epithalamus?of the?diencephalon, and is located just above the thalamus and is divided into two asymmetric halves: the medial habenula (MHb) and the lateral habenula (LHb)

(The pedunculopontine tegmental nucleus?receive input from the LHb. The pedunculopontine tegmental nucleus?provides one of the strongest excitatory inputs to the midbrain dopamine cells。這句話我是從哪里復(fù)制過(guò)來(lái)的呢？現(xiàn)在我忘了。確實(shí)，當(dāng)進(jìn)行利害邏輯思考時(shí)，人的欲望就消失了，不進(jìn)行利害邏輯思考時(shí)，人的行為會(huì)跟著欲望走，但是lateral habenula也可以直接抑制多巴胺啊，所以pedunculopontine tegmental nucleus?receive input from the LHb這個(gè)描述還是不能確定是否正確。如果人有兩個(gè)habenula，而且這兩個(gè)核團(tuán)還是不對(duì)稱的，一大一小，那么是不是就意味著其功能也是一大一小、一強(qiáng)一弱，是不是左、右手在趨利避害等功能方面存在左右差異，從而形成左、右利手？在我看來(lái)是這樣的。)

.These nuclei are hypothesized to be involved in regulation of monamines, such as?dopamine?and?serotonin.[4][5]?The medial habenula receives connections from posterior?septum pellucidum?and?diagonal band of Broca

(兩個(gè)cholinergic nuclei)

; the lateral habenula receives afferents?from the lateral?hypothalamus

（這里應(yīng)該只有興奮型軸突，那么就去興奮lateral habenula？）

,?nucleus accumbens

（nucleus accumbens包含core和shell兩部分，同時(shí)接受多巴胺彌散系統(tǒng)和額葉皮層的投射，其中多巴胺彌散系統(tǒng)的神經(jīng)細(xì)胞結(jié)構(gòu)及數(shù)量與額葉皮層第五分層的錐體細(xì)胞迥異，那么額葉皮層的投射應(yīng)該是屬于能夠精細(xì)調(diào)節(jié)的，所以在這里再存在一個(gè)nucleus accumbens對(duì)lateral habenula的抑制控制，其目的還是可以理解的，往往抑郁之人是額葉皮層過(guò)度活躍，那么就會(huì)存在通過(guò)nucleus accumbens對(duì)lateral habenula過(guò)度抑制，從而使人失去懲罰感覺(jué)，而產(chǎn)生自我傷害的行為（抑郁之人的多巴胺早已不活躍），此時(shí)ventral pallidum也被抑制，就算額葉皮層累了，降低了對(duì)nucleus accumbens的輸入，ventral pallidum會(huì)因?yàn)楸唤夥哦鴱?qiáng)烈活躍起來(lái)去抑制lateral habenula，依然讓人不能進(jìn)行懲罰感知，即不能產(chǎn)生避害行為。這里有兩個(gè)重要發(fā)現(xiàn)，多巴胺彌散系統(tǒng)和額葉皮層對(duì)nucleus accumbens的投射模式不同。血清素低才是NE放大環(huán)路中產(chǎn)生信號(hào)激增而導(dǎo)致的flight和fear反應(yīng)的根本原因，否則高serotonin濃度情況下只會(huì)對(duì)強(qiáng)烈的信號(hào)做出短暫的躲避行為。）

,?internal globus pallidus

（internal globus pallidus興奮時(shí)就會(huì)去抑制VL of thalamus和lateral habenula，導(dǎo)致主動(dòng)行為產(chǎn)生減少，同時(shí)抑制人或動(dòng)物的懲罰感覺(jué)，但是這不代表不產(chǎn)生行為，來(lái)自頂葉視覺(jué)皮層區(qū)的信息促發(fā)的行為屬于被動(dòng)行為，或者說(shuō)被意識(shí)允許的、非意識(shí)控制的行為；當(dāng)internal globus pallidus被putamen抑制時(shí)，主動(dòng)行為就很容易發(fā)生，此時(shí)lateral habenula就不被抑制，能夠?qū)ξｋU(xiǎn)做出避害邏輯反應(yīng)，即在產(chǎn)生主動(dòng)行為的過(guò)程中，如果發(fā)現(xiàn)危險(xiǎn)信息時(shí)，該信息就可以興奮lateral habenula，從而通過(guò)lateral habenula抑制多巴胺與serotonin，導(dǎo)致putamen的輸入減少?gòu)亩鴾p緩、乃至終止主動(dòng)行為，但是如果serotonin降低過(guò)快，會(huì)導(dǎo)致NE放大環(huán)路中的信號(hào)飆升而達(dá)到應(yīng)激反應(yīng)中的瞬間躲閃行為（該行為是被動(dòng)行為）?？傊?，因?yàn)閕nternal globus pallidus與putamen、lateral habenula、黑質(zhì)構(gòu)建的主動(dòng)運(yùn)動(dòng)控制系統(tǒng)，能夠?qū)崿F(xiàn)趨利避害的主動(dòng)行為，而由ventral pallidum構(gòu)建的系統(tǒng)實(shí)現(xiàn)的是對(duì)信息進(jìn)行好與壞的評(píng)價(jià)記憶。）

,?ventral pallidum

（nucleus accumbens不太興奮時(shí)，ventral pallidum就不會(huì)被其抑制而自發(fā)放電，從而去抑制dorsomedial thalamus和lateral habenula，即抑制了懲罰感覺(jué)。那么當(dāng)nucleus accumbens活躍時(shí)，那么lateral habenula就不怎么被nucleus accumbens抑制，就會(huì)使得人或動(dòng)物對(duì)構(gòu)成懲罰的事物敏感，能夠認(rèn)識(shí)到有害的事物。思想上認(rèn)識(shí)到有害事物對(duì)應(yīng)著lateral habenula活躍，那么就會(huì)抑制dopamine和serotonin，那么nucleus accumbens就會(huì)活動(dòng)量降低，進(jìn)而ventral pallidum活動(dòng)量增高，那么對(duì)lateral habenula的抑制增加，所以存在對(duì)有害事物的感知只發(fā)生一小會(huì)兒，所謂的“不好的”感受。其實(shí)額葉皮層對(duì)nucleus accumbens也有很多投射，過(guò)多的額葉輸入也會(huì)讓人對(duì)懲罰很敏感，而且這個(gè)懲罰感覺(jué)就是屬于持久型的，比如一塊完整的雪糕被咬了一口，三歲的小女兒就會(huì)因?yàn)榭吹饺笨诙罂?，原因是完整的雪糕?gòu)建了靜態(tài)恒定的多巴胺等輸入，少了一塊，就意味著少了一些多巴胺（或者皮層），那么對(duì)nucleus accumbens的恒定輸入產(chǎn)生變化，從而對(duì)lateral habenula的輸入產(chǎn)生變化，從而會(huì)造成懲罰感覺(jué)的產(chǎn)生（實(shí)際上expected reward只是產(chǎn)生很短時(shí)間的活動(dòng)增加，很快又恢復(fù)原態(tài)，大腦皮層的serotonin濃度卻是動(dòng)態(tài)變化的，雪糕變小，從而就需要更少的serotonin，從而更多的額葉皮層不被抑制，從而更多的投射到nucleus accumbens，從而更深地抑制ventral pallidum和多巴胺，從而lateral habenula更容易活躍，進(jìn)而進(jìn)入多巴胺與serotonin消減的惡性循環(huán)之中，就產(chǎn)生強(qiáng)烈的被懲罰感。）。這個(gè)則涉及DA獎(jiǎng)勵(lì)環(huán)路，這里就不過(guò)多公開了。）

, and diagonal band of Broca

(這里diagonal band of Broca對(duì)lateral habenula很有可能是投射GABAergic遞質(zhì)，因?yàn)樵陴囸I的時(shí)候吃的欲望特別強(qiáng)，尤其是看到了食物時(shí)，這時(shí)如果胡思亂想的話會(huì)減輕這種欲望，以前經(jīng)常在晚上下班回哈工大的路上餓的饑腸轆轆且思考很多，卻現(xiàn)在什么都想不起來(lái)，這應(yīng)該就是diagonal band of Broca活動(dòng)引發(fā)海馬皮層活動(dòng)，同時(shí)又有抑制型軸突投射至lateral habenula來(lái)抑制pedunculopontine nucleus來(lái)抑制欲望。)(diagonal band of Broca和medial septal nucleus都是cholinergic nuclei，但是medial septal nucleus不投射到lateral habenula，diagonal band of Broca投射到lateral habenula。之前我就預(yù)測(cè)這兩個(gè)cholinergic nuclei對(duì)海馬皮層的投射模式是行為上有區(qū)別的，現(xiàn)在我找到支持的證據(jù)了。diagonal band of Broca活動(dòng)時(shí)，海馬皮層活躍帶來(lái)復(fù)雜的思考活動(dòng)（因?yàn)閏ingulate cortex等等），同時(shí)又激發(fā)lateral habenula，進(jìn)一步激發(fā)pedunculopontine tegmental nucleus，從而試圖去激發(fā)substantia nigra pars compacta；這種reward感的激發(fā)不是來(lái)自于副交感系統(tǒng)器官，而是來(lái)自虛幻的想象世界，其reward很有可能是帶來(lái)對(duì)副交感系統(tǒng)器官的傷害，這就是人特有的榮譽(yù)獎(jiǎng)勵(lì)機(jī)制，比如我父輩在艱難時(shí)刻所崇尚的精神支柱。這也證明了medial septal nucleus是無(wú)壓力狀態(tài)下的海馬皮層運(yùn)作狀態(tài)，pedunculopontine tegmental nucleus的興奮是通過(guò)副交感系統(tǒng)器官的活動(dòng)激發(fā)的，而副交感系統(tǒng)器官的活動(dòng)是通過(guò)食物（腸胃系統(tǒng)）和精囊內(nèi)容物、前列腺內(nèi)容物、輸精管內(nèi)容物（生殖系統(tǒng)）來(lái)刺激的，別忘了anterior insular cortex也可以對(duì)副交感系統(tǒng)器官進(jìn)行影響，而anterior cingulate cortex和頭面部神經(jīng)nuclei也投射到anterior insular cortex，換句話說(shuō)海馬皮層的活動(dòng)和頭面部表情可以影響anterior insular cortex；而diagonal band of Broca是壓力狀態(tài)下的海馬皮層運(yùn)作狀態(tài)，diagonal band of Broca可以直接興奮lateral habenula，而lateral habenula直接興奮pedunculopontine tegmental nucleus，從而不需要頭面部神經(jīng)nuclei和副交感系統(tǒng)器官來(lái)興奮pedunculopontine tegmental nucleus，進(jìn)而興奮SNpc，這樣的人性格上喜怒不形于色，面部表情很克制，內(nèi)心依然很火熱（SNpc的興奮），我就是這樣性格的人。分析到這里，我終于知道自己內(nèi)部的運(yùn)作狀態(tài)，尤其是海馬皮層的cholinergic控制狀態(tài)，diagonal band of Broca和medial septal nucleus的控制狀態(tài)是完全不同的兩種類型，二者最終興奮pedunculopontine tegmental nucleus進(jìn)而興奮basal ganglia的結(jié)果相同，但是二者控制方式的副產(chǎn)品完全不同，一個(gè)喜形于色，一個(gè)不喜形于色。我的研究太成功了。別忘了serotonin也可以“inhibit”diagonal band of Broca和medial septal nucleus)

.[2]?As a whole, this complexly interconnected region is part of the?dorsal diencephalic conduction?(DDC) system, responsible for relaying information from the limbic system to the?midbrain,?hindbrain, and?medial forebrain.[6][7]

The right and left habenular nuclei are connected to each other by the?habenular commissure.

（如果lateral habenular nuclei是抑制型的，那么左右lateral habenular nuclei的溝通產(chǎn)生的效果是：當(dāng)一側(cè)lateral habenular nuclei強(qiáng)烈活動(dòng)時(shí)，另一側(cè)的lateral habenular nuclei被抑制？）

Habenula nuclear divisions:

·?lateral habenular nucleus (hier-278?at?NeuroNames, )

·?medial habenular nucleus (hier-279?at?NeuroNames, )

The?pineal gland?is attached to the brain in this region.

Nerve impulses?from the habenular nuclei are transmitted to the?septal nuclei?via the?stria medullaris, which is found on the medial surface of the thalamus.[citation needed]?Axons from habenular nucleus pass to interpeduncular fossa, the tectum of midbrain, the thalamus and the reticular formation of the midbrain.

Motivation and addiction[edit]

Recent exploration of the habenular nuclei has begun to associate the structure with an organism's current mood, feeling of motivation, and reward recognition.（經(jīng)過(guò)前面的分析，你這句話當(dāng)然是對(duì)的，不過(guò)，挺接近廢話的。）[8]?Previously, the LHb has been identified as an "anti-reward" signal, but recent research suggests that the LHb helps identify preference, helping the brain to discriminate between potential actions and subsequent motivation decisions.[9]?In a study using a?Pavlovian conditioning?model, results showed an increase in the habenula response.[10]?This increase coincided with conditioned stimuli associated with more aversive punishments (ie. electric shock).[10]?Therefore, researchers speculate that inhibition or damage to the LHb resulting in a failure to process such information may lead to random motivation behavior.[9][10]

LHb is especially important in understanding the reward and motivation relationship as it relates to addictive behaviors.[8]?The LHb inhibits?dopaminergic?neurons, decreasing the release of dopamine.[11]?It was determined by several animal studies that receiving a reward coincided with elevated dopamine levels, but once the learned association was learned by the animal, dopamine levels remain elevated（這里是不是筆誤，應(yīng)該是unelevated）, only decreasing when the reward is removed.[1][5][8][11]?Therefore, dopamine levels only increase with unpredicted rewards and with a "negative prediction error"（這里是不是筆誤，應(yīng)該是decrease with a "negative prediction error"，少了一個(gè)decrease。）.[1]?Moreover, it was determined that removal of an anticipated award activated LHb, inhibited dopamine levels

（在沒(méi)有看到這句話之前，按照我的理論體系，就已經(jīng)推導(dǎo)預(yù)測(cè)了這個(gè)結(jié)果。不知道這句話是不是來(lái)自實(shí)驗(yàn)結(jié)果的直接觀察。）

.[1]?This finding helps explain why addictive drugs are associated with elevated dopamine levels.[1]

Nicotine and nAChRs[edit]

According to the?National Institute on drug Abuse, 1 in 5?preventable deaths, in the United States, is caused by?tobacco?use.[12]?Nicotine?is the addictive drug found in most tobacco products and is easily absorbed by the bloodstream of the body.[12]?Despite common misconceptions regarding the relaxing effects of tobacco and nicotine use, behavioral testing in animals has demonstrated nicotine to have an anxiogenic effect.[13]?Nicotinic acetylcholine receptors?(nAChRs) have been identified as the primary site for nicotine activity and regulate consequent cellular polarization.[14]?nAChRs are made up a number of α and β subunits and are found in both the LHb and MHb

（nAChRs是興奮型受體，那么那些能投射到habenula的乙酰膽堿能核團(tuán)的功能就清楚了。）

, where research suggests they may play a key role in addiction and withdrawal behaviors.[14][15]

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This article?appears to contradict the article?habenula.?Please see discussion on the linked?talk page.?(February 2013)?(Learn how and when to remove this template message)

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