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Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The basal ganglia have been implicated in a wide range of functions, as evidenced by the distribution of the inputs they receive. Practically all areas of the cerebral cortex project essentially topographically to the dorsal striatum, thence to other nuclei, and back through the feedback loops via the thalamus to the same cortical areas of origin of the given input to the basal ganglia. The dorsal striatum also receives: (i) feedback input from thalamic nuclei, (ii) dopaminergic input from the ventral tegmental area of the midbrain, which is believed to be part of the “reward” system in the brain, and (iii) serotonergic input from the raphe nuclei, which are a group of nuclei in the brainstem that are a major source of serotonin to the rest of the brain. Serotonin is a neurotransmitter that influences many brain functions, including mood, behavior, sleep, memory, and learning.
Consciousness, EEG, Sleep and Emotions
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The locus coeruleus, a group of neurons containing norepinephrine (noradrenaline) as a neurotransmitter, is found in the pontine reticular formation. The raphe nuclei are formed by another group of neurons lying in the midline of the pons. Some of these neurons in the pons and midbrain send axons to excite or inhibit the thalamus. Neural impulses from the reticular formation can modulate the activity of the thalamic pacemakers and thus influence cortical neuronal excitability. The intralaminar and anterior thalamic nuclei are non-specific nuclei of the thalamus which excite the cerebral cortex. Axons from the non-specific nuclei can also stimulate inhibitory interneurons linked to the thalamic nuclei to produce drowsiness. Lesions diffusely affecting the cerebral hemispheres or directly affecting the reticular activating system can impair consciousness.
Central Regulation of Brainstem Gastric Vago-Vagal Control Circuits
Published in Sue Ritter, Robert C. Ritter, Charles D. Barnes, Neuroanatomy and Physiology of Abdominal Vagal Afferents, 2020
The physiological significance of the nRO input to the DVC is not known at this time. It is interesting to note, however, that the raphe nuclei, in general, appear to be involved in the transition between sleep and wakefulness.42 Such changes in arousal are highly correlated with gross changes in gastrointestinal motility.52,54 Thus, it is possible that the raphe nuclei control the transitions from sleep and waking as well as the associated changes in gastrointestinal function appropriate to the arousal state. The understanding of this mechanism may be significant to elucidating the causes of the arousal related onset of irritable bowel syndrome.52,54
Correlations with REM sleep behavior disorder severity in isolated rapid eye movement sleep behavior disorders patients
Published in International Journal of Neuroscience, 2023
Sang Jin Kim, Eun Ju Chung, Ki-Hwan Ji, Mi-Ri Kang, Jin Yong Hong, Sunseong Lee, Ji Sun Park, Jungsu S. Oh, Jae Seung Kim, Suk Yun Kang
The correlation between pain and visuospatial dysfunction with RBD severity may be associated with RBD pathophysiology. This pathophysiology is currently poorly understood, but RBD is thought to be associated with several nuclei in the pontomedullary brainstem that include the locus coeruleus, subcoeruleus/sublateral dorsal nucleus, laterodorsal tegmental nuclei, the PPN, and medullary magnocellular reticular formation [8]. These nuclei play a role in pain modulation, visuospatial attention, and cognition including visuospatial function and memory [24–26]. The locus coeruleus is a norepinephrine-producing nucleus in the dorsal pons, and projects to the brain widely and is involved in homeostasis, sensory processing, and cognitive and motor function [24,26]. The raphe nuclei are serotonin-producing nuclei in the midline from the medulla to the midbrain and are also involved in sensory processing that includes pain, heat, touch [27], and visual orientation [28]. One recent study reported increased thermal detection threshold in iRBD patients, and they assumed that peripheral small nerve fibers might be associated because they did not find a difference in laser evoked potentials and conditioned pain modulation between iRBD patients and controls. However, more studies are needed, because they did not perform skin biopsies to check nerve pathology and did not assess the presence and severity of pain in iRBD patients [29]. Besides, there was no PSG data to determine RBD severity in that study.
Pindolol potentiates the antidepressant effect of venlafaxine by inhibiting 5-HT1A receptor in DRN neurons of mice
Published in International Journal of Neuroscience, 2021
Serotonin (5-HT) has major roles in the regulation of mood, appetite, sleep and memory in CNS [1]. Decreases in the level of 5-HT, which is synthesized by the serotonergic neurons of the raphe nuclei, results in some psychiatric conditions like major depression (MD). Especially, the dorsal raphe nucleus (DRN) among the raphe nuclei sends serotonergic projections to limbic system and regulate mood. Clarification of synthesis, oscillation and reuptake processes of 5-HT in the DRN has importance to find better and more effective cures of mood disorders. MD is one of the most common psychiatric disorders [2]. It ranks second in the life-long burden of disease in developed countries and is expected to rank first by 2030 [3]. MD is mainly caused by decreased level of 5-HT in neurosynaptic junction between serotonergic raphe nuclei neurons and postsynaptic neurons in brain [4]. Increases in the number of presynaptic somatodendritic 5-HT1A autoreceptors in the raphe nuclei as well as decreases in the number of postsynaptic 5-HT1A receptors augment the risk of MD [5].
Updated review on the link between cortical spreading depression and headache disorders
Published in Expert Review of Neurotherapeutics, 2021
Doga Vuralli, Hulya Karatas, Muge Yemisci, Hayrunnisa Bolay
There is a complex and poorly understood relationship between sleep hygiene changes and migraine. Migraineurs report deprived sleep as a precipitating factor of an attack. Sleep disturbances also have an important role in the development and persistence of chronic migraine [85]. Serotonin (5-HT), which affects many human behaviors including sleep, mood, appetite, sexual function, and pain, may have a key role in triggering migraine. From sleep perspective, serotonin promotes wakefulness and inhibits rapid eye movement (REM) sleep and clinical studies showed that migraine patients have low serotonin levels interictally and increased levels during an attack [86]. Migraineurs having attacks associated with unhygienic sleep experience increased awakenings in the night preceding headache [87]. It is not known how increased 5-HT levels are involved in the trigeminovascular nociceptive pathway. However, rats with low 5-HT levels have increased numbers of CSD waves [86]. The dorsal raphe nucleus in the pons and midbrain produces 5-HT. The dorsal raphe nucleus has a crucial role in sleep and the cessation of the serotonergic neuron firing initiates REM [88]. Migraine patients may also have subcortical serotoninergic system dysfunction resulting in unhygienic sleep [89].