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Neuropharmacologic considerations in the treatment of vegetative state and minimally conscious state following brain injury
Published in Mark J. Ashley, David A. Hovda, Traumatic Brain Injury, 2017
Dorsal projections from the brain stem ARAS reach the thalamus. The thalamus serves as the main relay and filtering station for ascending sensory information. Without the thalamus, most sensory input would not reach the cortex. Activation of the thalamic nuclei by cholinergic and glutaminergic fibers of the ARAS facilitates transmission of sensory input to higher cortical regions. The thalamic nuclei have both afferent and efferent connections with the cerebral cortex and brain stem. The thalamic reticular nucleus, in particular, is involved in the process of sensory gating. Gating of the stream of sensory data allows attention to be selectively focused on some aspects of sensory input and not others. The ascending pathways from the thalamus to the primary sensory areas of the cerebral cortex are predominantly glutaminergic. From the primary sensory areas, collateral connections proceed to the sensory association areas, where information is processed, interpreted, and consciously experienced.
Helping You Understand Dr. Goldstein's Book
Published in Katie Courmel, A Companion Volume to Dr. Jay A. Goldstein's Betrayal by the Brain, 2013
Normal Function—The thalamic reticular nucleus is a thin layer of cells wrapped around the dorsal thalamus. Providing the earliest developmental linkage between the thalamus and the cortex, the RT connects the numerous "relay nuclei" of the thalamus. The relay nuclei are the structures by which the thalamus receives sensory information from the body. The RT then regulates the transmission of pain and other signals to the cortex. The RT controls interneurons that release GABA, an inhibitory neurotransmitter whose selective secretion can send a sensory message of either pain or touch to the cortex. When the sensation is pain, GAB A inhibits messages regarding touch.
Thalamic neuromodulation in epilepsy: A primer for emerging circuit-based therapies
Published in Expert Review of Neurotherapeutics, 2023
Bryan Zheng, David D. Liu, Brian B Theyel, Hael Abdulrazeq, Anna R. Kimata, Peter M Lauro, Wael F. Asaad
The thalamus is a cluster of nuclei that are grouped based on shared patterns of connectivity with cortical and subcortical areas and are enveloped within the shell-like thalamic reticular nucleus (TRN). Topographically organized thalamocortical and corticothalamic projections are the basic, modular elements around which more elaborate thalamic circuits are built. The surrounding TRN is a major source of feedforward and feedback inhibition. Meanwhile, in contrast to the principal nuclei that connect to relatively circumscribed areas of cortex, intralaminar nuclei are more diffuse structures with correspondingly broader cortical interactions. Further, the borders between principal nuclei are not always distinct and the anatomical and functional perspectives do not consistently map directly onto one another. As such, alternative classification schemes based on thalamocortical circuitry may more clearly lay the framework for therapeutic thalamic neuromodulation.
Sleep-promoting activity of lotus (Nelumbo nucifera) rhizome water extract via GABAA receptors
Published in Pharmaceutical Biology, 2022
Yejin Ahn, Singeun Kim, Chunwoong Park, Jung Eun Kim, Hyung Joo Suh, Kyungae Jo
Currently, the understanding on how stress affects sleep is obscure, but is suspected to be closely related to sleep and the activity of the hypothalamic-pituitary-adrenal (HPA) axis. In the early stages of sleep, slow wave sleep is dominant, and the activity of the HPA axis is the lowest and continuously suppressed. Conversely, in the second half of sleep, REM sleep dominates and the activity of HPA secretion increases, approaching a daily maximum immediately after waking up. The ventrolateral preoptic nucleus (VLPO) located in the hypothalamus acts as a switch to initiate sleep. Activated VLPO neurons secrete inhibitory neurotransmitters, such as GABA, to inhibit the areas responsible for arousal and induce sleep (Saper et al. 2005). GABAs are activated during sleep and inhibit monoamine and histamine-secreting regions to prevent waking. The thalamic reticular nucleus also contains GABA as a neurotransmitter and generates sleep spindles (Mignot et al. 2002).
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
Sensory processing requires a synchronous activity of both first-order and higher-order thalamic nuclei and corresponding cerebral cortical areas. CSD was shown to influence thalamus and SD waves were detected in thalamic reticular nucleus (TRN) [70]. TRN is a strategically positioned nucleus and tunes sensory impulse trafficking between thalamus and cortex and also plays a significant role in sleep, attention, and sensory discrimination [71,72]. TRN is the subcortical generator of sleep spindles and is an important center for sleep regulation [73–75]. TRN involvement during CSD, has important functional consequences such as increased sensory inputs to the cerebral cortex and heightened reaction to various sensory stimuli resulting in photophobia, phonophobia or allodynia [70,76]. The role of sleep in migraine may be associated with dysfunctional TRN [10,70] as sleep disturbances may trigger migraine and migraine attack may be ameliorated with sleep.