丘脑通路主要由脑桥被盖中的胆碱能神经元组成,而下丘脑通路主要由释放单胺神经递质(即多巴胺、去甲肾上腺素、血清素和组胺)的神经元组成。 [3][6] ARAS 中释放谷氨酸的神经元相对于单胺能和胆碱能神经元的发现要晚得多。 [8] ARAS 的谷氨酸能成分包括下丘脑的一个核和多个脑干核。 [4][8][9]下丘脑外侧的食欲素神经元支配上行网状激活系统的每个组成部分并协调整个系统内的活动。 [5][10][11]
直接电刺激 ARAS 会在猫中产生疼痛反应,并引发人类对疼痛的口头报告。[來源請求]</link>[需要引用]猫的上行网状结构激活会导致瞳孔散大, [27]这可能是由于长期疼痛引起的。这些结果表明 ARAS 回路与生理疼痛通路之间存在某种关系。 [27]
病理学
ARAS 的一些病理可能归因于年龄,因为随着年龄的增长,ARAS 的反应性似乎普遍下降。 [28]电耦合[C]的变化被认为可以解释 ARAS 活动的一些变化:如果耦合下调,则高频同步(伽马带)也会相应减少。相反,上调的电耦合会增加快节奏的同步,从而导致觉醒和快速眼动睡眠驱动力的增加。 [30]具体来说,ARAS 的破坏与以下疾病有关:
接下来,通过在中脑前部的内侧和外侧部分放置损伤来评估这个新发现的中继系统的重要性。 ARAS 中脑中断的猫进入深度睡眠并显示出相应的脑电波。以另一种方式,上行听觉和躯体通路受到类似干扰的猫表现出正常的睡眠和觉醒,并且可以通过物理刺激唤醒。因为这些外部刺激在到达皮层的途中会被中断所阻碍,这表明上行传输必须通过新发现的 ARAS。
最后,马贡记录了脑干内侧部分的电位,发现听觉刺激直接激发了网状激活系统的部分区域。此外,坐骨神经的单次电击刺激也激活了内侧网状结构、下丘脑和丘脑。 ARAS 的兴奋不依赖于通过小脑回路的进一步信号传播,因为在去小脑和去皮后获得了相同的结果。研究人员提出,中脑网状结构周围的一列细胞接收来自脑干所有上升束的输入,并将这些传入信号传递到皮质,从而调节觉醒。 [40][22]
^ 3.03.13.23.33.43.53.63.73.8Iwańczuk W, Guźniczak P. Neurophysiological foundations of sleep, arousal, awareness and consciousness phenomena. Part 1. Anaesthesiol Intensive Ther. 2015, 47 (2): 162–167. PMID 25940332. doi:10.5603/AIT.2015.0015. The ascending reticular activating system (ARAS) is responsible for a sustained wakefulness state. It receives information from sensory receptors of various modalities, transmitted through spinoreticular pathways and cranial nerves (trigeminal nerve – polymodal pathways, olfactory nerve, optic nerve and vestibulocochlear nerve – monomodal pathways). These pathways reach the thalamus directly or indirectly via the medial column of reticular formation nuclei (magnocellular nuclei and reticular nuclei of pontine tegmentum). The reticular activating system begins in the dorsal part of the posterior midbrain and anterior pons, continues into the diencephalon, and then divides into two parts reaching the thalamus and hypothalamus, which then project into the cerebral cortex (Fig. 1). The thalamic projection is dominated by cholinergic neurons originating from the pedunculopontine tegmental nucleus of pons and midbrain (PPT) and laterodorsal tegmental nucleus of pons and midbrain (LDT) nuclei [17, 18]. The hypothalamic projection involves noradrenergic neurons of the locus coeruleus (LC) and serotoninergic neurons of the dorsal and median raphe nuclei (DR), which pass through the lateral hypothalamus and reach axons of the histaminergic tubero-mamillary nucleus (TMN), together forming a pathway extending into the forebrain, cortex and hippocampus. Cortical arousal also takes advantage of dopaminergic neurons of the substantia nigra (SN), ventral tegmenti area (VTA) and the periaqueductal grey area (PAG). Fewer cholinergic neurons of the pons and midbrain send projections to the forebrain along the ventral pathway, bypassing the thalamus [19, 20].
^ 4.04.14.24.34.44.54.64.7Brudzynski SM. The ascending mesolimbic cholinergic system – a specific division of the reticular activating system involved in the initiation of negative emotional states. Journal of Molecular Neuroscience. July 2014, 53 (3): 436–445. PMID 24272957. S2CID 14615039. doi:10.1007/s12031-013-0179-1. Understanding of arousing and wakefulness-maintaining functions of the ARAS has been further complicated by neurochemical discoveries of numerous groups of neurons with the ascending pathways originating within the brainstem reticular core, including pontomesencephalic nuclei, which synthesize different transmitters and release them in vast areas of the brain and in the entire neocortex (for review, see Jones 2003; Lin et al. 2011). They included glutamatergic, cholinergic, noradrenergic, dopaminergic, serotonergic, histaminergic, and orexinergic systems (for review, see Lin et al. 2011). ... The ARAS represented diffuse, nonspecific pathways that, working through the midline and intralaminar thalamic nuclei, could change activity of the entire neocortex, and thus, this system was suggested initially as a general arousal system to natural stimuli and the critical system underlying wakefulness (Moruzzi and Magoun 1949; Lindsley et al. 1949; Starzl et al. 1951, see stippled area in Fig. 1). ... It was found in a recent study in the rat that the state of wakefulness is mostly maintained by the ascending glutamatergic projection from the parabrachial nucleus and precoeruleus regions to the basal forebrain and then relayed to the cerebral cortex (Fuller et al. 2011). ... Anatomical studies have shown two main pathways involved in arousal and originating from the areas with cholinergic cell groups, one through the thalamus and the other, traveling ventrally through the hypothalamus and preoptic area, and reciprocally connected with the limbic system (Nauta and Kuypers 1958; Siegel 2004). ... As counted in the cholinergic connections to the thalamic reticular nucleus ...
^ 5.05.15.25.35.45.55.65.75.8Schwartz MD, Kilduff TS. The Neurobiology of Sleep and Wakefulness. The Psychiatric Clinics of North America. December 2015, 38 (4): 615–644. PMC 4660253. PMID 26600100. doi:10.1016/j.psc.2015.07.002. This ascending reticular activating system (ARAS) is comprised of cholinergic laterodorsal and pedunculopontine tegmentum (LDT/PPT), noradrenergic locus coeruleus (LC), serotonergic (5-HT) Raphe nuclei and dopaminergic ventral tegmental area (VTA), substantia nigra (SN) and periaqueductal gray projections that stimulate the cortex directly and indirectly via the thalamus, hypothalamus and BF.6, 12-18 These aminergic and catecholaminergic populations have numerous interconnections and parallel projections which likely impart functional redundancy and resilience to the system.6, 13, 19 ... More recently, the medullary parafacial zone (PZ) adjacent to the facial nerve was identified as a sleep-promoting center on the basis of anatomical, electrophysiological and chemo- and optogenetic studies.23, 24 GABAergic PZ neurons inhibit glutamatergic parabrachial (PB) neurons that project to the BF,25 thereby promoting NREM sleep at the expense of wakefulness and REM sleep. ... The Hcrt neurons project widely throughout the brain and spinal cord92, 96, 99, 100 including major projections to wake-promoting cell groups such as the HA cells of the TM,101 the 5-HT cells of the dorsal Raphe nuclei (DRN),101 the noradrenergic cells of the LC,102 and cholinergic cells in the LDT, PPT, and BF.101, 103 ... Hcrt directly excites cellular systems involved in waking and arousal including the LC,102, 106, 107 DRN,108, 109 TM,110-112 LDT,113, 114 cholinergic BF,115 and both dopamine (DA) and non-DA neurons in the VTA.116, 117
^ 6.06.16.26.36.46.5Malenka RC, Nestler EJ, Hyman SE. Chapter 12: Sleep and Arousal 2nd. New York: McGraw-Hill Medical. 2009: 295. ISBN 978-0071481274. The RAS is a complex structure consisting of several different circuits including the four monoaminergic pathways ... The norepinephrine pathway originates from the locus ceruleus (LC) and related brainstem nuclei; the serotonergic neurons originate from the raphe nuclei within the brainstem as well; the dopaminergic neurons originate in ventral tegmental area (VTA); and the histaminergic pathway originates from neurons in the tuberomammillary nucleus (TMN) of the posterior hypothalamus. As discussed in Chapter 6, these neurons project widely throughout the brain from restricted collections of cell bodies. Norepinephrine, serotonin, dopamine, and histamine have complex modulatory functions and, in general, promote wakefulness. The PT in the brain stem is also an important component of the ARAS. Activity of PT cholinergic neurons (REM-on cells) promotes REM sleep. During waking, REM-on cells are inhibited by a subset of ARAS norepinephrine and serotonin neurons called REM-off cells.
^ 8.08.18.28.3Saper CB, Fuller PM. Wake-sleep circuitry: an overview. Current Opinion in Neurobiology. June 2017, 44: 186–192. PMC 5531075. PMID 28577468. doi:10.1016/j.conb.2017.03.021. Parabrachial and pedunculopontine glutamatergic arousal system Retrograde tracers from the BF have consistently identified one brainstem site of input that is not part of the classical monoaminergic ascending arousal system: glutamatergic neurons in the parabrachial and pedunculopontine nucleus ... Juxtacellular recordings from pedunculopontine neurons have found that nearly all cholinergic neurons in this region, as well as many glutamatergic and GABAergic neurons, are most active during wake and REM sleep [25], although some of the latter neurons were maximally active during either wake or REM, but not both. ... [Parabrachial and pedunculopontine glutamatergic neurons] provide heavy innervation to the lateral hypothalamus, central nucleus of the amygdala, and BF
^ 9.09.1Pedersen NP, Ferrari L, Venner A, Wang JL, Abbott SG, Vujovic N, Arrigoni E, Saper CB, Fuller PM. Supramammillary glutamate neurons are a key node of the arousal system. Nature Communications. November 2017, 8 (1): 1405. Bibcode:2017NatCo...8.1405P. PMC 5680228. PMID 29123082. doi:10.1038/s41467-017-01004-6. Basic and clinical observations suggest that the caudal hypothalamus comprises a key node of the ascending arousal system, but the cell types underlying this are not fully understood. Here we report that glutamate-releasing neurons of the supramammillary region (SuMvglut2) produce sustained behavioral and EEG arousal when chemogenetically activated.
^Malenka RC, Nestler EJ, Hyman SE. Chapter 12: Sleep and Arousal 2nd. New York: McGraw-Hill Medical. 2009: 295. ISBN 978-0071481274. Orexin neurons are located in the lateral hypothalamus. They are organized in a widely projecting manner, much like the monoamines (Chapter 6), and innervate all of the components of the ARAS. They excite the REM-off monoaminergic neurons during wakefulness and the PT cholinergic neurons during REM sleep. They are inhibited by the VLPO neurons during NREM sleep.
^ 12.012.1Cherasse Y, Urade Y. Dietary Zinc Acts as a Sleep Modulator. International Journal of Molecular Sciences. November 2017, 18 (11): 2334. PMC 5713303. PMID 29113075. doi:10.3390/ijms18112334. The regulation of sleep and wakefulness involves many regions and cellular subtypes in the brain. Indeed, the ascending arousal system promotes wakefulness through a network composed of the monaminergic neurons in the locus coeruleus (LC), histaminergic neurons in the tuberomammilary nucleus (TMN), glutamatergic neurons in the parabrachial nucleus (PB) ...
^ 14.014.1Kinomura S, Larsson J, Gulyás B, Roland PE. Activation by attention of the human reticular formation and thalamic intralaminar nuclei. Science. January 1996, 271 (5248): 512–515. Bibcode:1996Sci...271..512K. PMID 8560267. S2CID 43015539. doi:10.1126/science.271.5248.512. This corresponds to the centro-median and centralis lateralis nuclei of the intralaminar group
^VandenBos, Gary R (编). animal hypnosis. APA dictionary of psychology 2nd (Washington, DC: American Psychological Association). 2015: 57. ISBN 978-1433819445. doi:10.1037/14646-000. a state of motor nonresponsiveness in nonhuman animals, produced by stroking, salient stimuli, or physical restraint. It is called “hypnosis” because of a claimed resemblance to human hypnosis and trance
^ 17.017.1Jang SH, Kwon HG. The direct pathway from the brainstem reticular formation to the cerebral cortex in the ascending reticular activating system: A diffusion tensor imaging study. Neurosci. Lett. October 2015, 606: 200–203. PMID 26363340. S2CID 37083435. doi:10.1016/j.neulet.2015.09.004.
^ 21.021.1Reiner, P. B. Are mesopontine cholinergic neurons either necessary or sufficient components of the ascending reticular activating system?. Seminars in Neuroscience. 1995, 7 (5): 355–359. S2CID 5575547. doi:10.1006/smns.1995.0038.
^Pearson, Keir G; Gordon, James E. Kandel , 编. Chapter 41 / Posture 5th. United States: McGraw-Hill. 2013. The Brain Stem and Cerebellum Integrate Sensory Signals for Posture, p. 954. ISBN 978-0071390118.Editors list列表中的|first2=缺少|last2= (帮助); Editors list列表中的|first4=缺少|last4= (帮助)