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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.
The stress-response
Published in Herman Staudenmayer, Environmental Illness, 2018
Serotonin (5-HT) is secreted from raphe neurons which have their origin in the median raphe nuclei located in the pons and medulla of the brain stem. Nerve fibers from these nuclei spread widely in the reticular formation and upward into the limbic system. They extend downward into the spinal cord where they serve to inhibit pain. Decreased 5-HT activity in central neurons reduces the inhibitory influence on the LC-NE system. This is one mechanism hypothesized for increased anxiety and panic (Lingjaerde, 1985).
Physical Hazards of Space Exploration and the Biological Bases of Behavioral Health and Performance in Extreme Environments
Published in Lauren Blackwell Landon, Kelley J. Slack, Eduardo Salas, Psychology and Human Performance in Space Programs, 2020
Julia M. Schorn, Peter G. Roma
These two domains are the most “basic” as they serve the most essential biobehavioral functions, such as sleep–wakefulness and motor actions. Arousal/regulatory systems provide homeostatic regulation of sleep, wake, and arousal. When teams live and work in space, wakefulness and attention are required to correctly execute mission tasks and maintain mission systems, which could potentially have fatal consequences if poorly performed. Within the brain, the suprachiasmatic nucleus (SCN) in the hypothalamus is critical for regulating circadian rhythms and is known as the “master clock” (Dubocovich, 2007; Ebling, 1996). Our circadian rhythm is also influenced by external cues, the most prominent being light. Sunlight stimulates wakefulness while darkness is accompanied by melatonin production. Melatonin, the neurohormone associated with sleep, is suppressed when exposed to blue-enriched white light. Light-sensitive receptor cells in the retina project to the SCN. The pathway from light receptors to SCN eventually ends in the pineal gland, which secretes melatonin. The SCN also controls related functions, such as body temperature, hormone secretion, urine production, and blood pressure. The SCN also receives input of the neurotransmitter serotonin from the dorsal raphe nucleus in the brainstem, which attenuates light-induced shifts in circadian phase (Rosenwasser, 2009). Different neurotransmitters, namely acetylcholine and noradrenaline, project from the basal forebrain to different areas in the cortex and support sustained attention (Dalley et al., 2001; Sarter, Givens, & Bruno, 2001). Additionally, many hormones like cortisol, testosterone, and oxytocin also exhibit natural circadian rhythms and are associated with basic sleep–wake rhythms (Amico, Tenicela, Johnston, & Robinson, 1983; Haus, 2007). Circadian rhythm disturbances are associated with multiple psychiatric conditions, including major depression, schizophrenia, and bipolar disorder (Cohrs, 2008; Pilz et al., 2018; Vadnie & McClung, 2017).
A device review of Relivion®: an external combined occipital and trigeminal neurostimulation (eCOT-NS) system for self-administered treatment of migraine and major depressive disorder
Published in Expert Review of Medical Devices, 2021
Oved Daniel, Roni Sharon, Stewart J. Tepper
The ophthalmic division of the trigeminal nerve has four branches that can be targeted, and the cervically-derived greater occipital nerve has two larger branches that can be targeted (Figure 1). The Relivion® headset integrates three pairs of output electrodes that contact and deliver stimulation pulses to the patient’s scalp at the forehead (two pairs of electrodes) and occiput (one pair of electrodes). The four frontal electrodes stimulate the trigeminal supraorbital and supratrochlear nerve branches, and the two posterior electrodes stimulate the greater occipital nerve branches. Thanks to its unique multi-channel design and six-electrode configuration, the Relivion® is designed to deliver an unprecedented amount of electrical stimulation via its three adaptive output channels, compared to traditional devices. According to the hypothesized mechanism of action, once signals from the trigeminal and occipital nerves enter the brain, it activates afferent nerve fibers that converge on the same second-order neurons in the TCC with common pathways to the nucleus tractus solitarius and locus coeruleus and raphe nuclei, as well as to higher centers in the brain including the thalamus, hypothalamus, amygdala, reticular activating system, limbic forebrain and anterior cingulate cortex. By releasing anti-nociceptive neurotransmitters such as norepinephrine (Locus Coeruleus) and serotonin (Raphe Nuclei), these brain regions are involved in modulation of pain, mood and anxiety [24,25].