Littérature scientifique sur le sujet « Lateral hypothalamu »
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Articles de revues sur le sujet "Lateral hypothalamu"
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Wilent, W. Bryan, Michael Y. Oh, Catherine Buetefisch, Julian E. Bailes, Diane Cantella, Cindy Angle et Donald M. Whiting. « Mapping of microstimulation evoked responses and unit activity patterns in the lateral hypothalamic area recorded in awake humans ». Journal of Neurosurgery 115, no 2 (août 2011) : 295–300. http://dx.doi.org/10.3171/2011.3.jns101574.
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Major contributions to the understanding of human brain function have come from detailed clinical reports of responses evoked by electrical stimulation and specific brain regions during neurosurgical procedures in awake humans. In this study, microstimulation evoked responses and extracellular unit recordings were obtained intraoperatively in 3 awake patients undergoing bilateral implantation of deep brain stimulation electrodes in the lateral hypothalamus. The microstimulation evoked responses exhibited a clear anatomical distribution. Anxiety was most reliably evoked by stimulation directed ventromedially within or adjacent to the ventromedial nucleus of the hypothalamus, nausea was most reliably evoked by stimulation directed at the center of the lateral hypothalamus, and paresthesias were most reliably evoked by stimulation at the border of the lateral hypothalamus and basal nuclei. Regarding the unit recordings, the firing rates of individual neurons did not have an anatomical distribution, but a small subpopulation of neurons located at the border of the lateral hypothalamus and basal nuclei exhibited a fast rhythmically bursting behavior with an intraburst frequency of 200–400 Hz and an interburst frequency of 10–20 Hz. Based on animal studies, the lateral hypothalamic area and surrounding hypothalamic nuclei are putatively involved with a variety of physiological, behavioral, and sensory functions. The lateral hypothalamus is situated to play a dynamic and complex role in human behavior and this report further shows that to be true. In addition, this report should serve as a valuable resource for future intracranial work in which accurate targeting within this region is required.
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Take, S., D. Uchimura, Y. Kanemitsu, T. Katafuchi et T. Hori. « Interferon-alpha acts at the preoptic hypothalamus to reduce natural killer cytotoxicity in rats ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 268, no 6 (1 juin 1995) : R1406—R1410. http://dx.doi.org/10.1152/ajpregu.1995.268.6.r1406.
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We previously demonstrated that an intracerebroventricular injection of recombinant human interferon-alpha (rhIFN-alpha) reduced the cytotoxicity of splenic natural killer (NK) cells in rats and mice. In the present study, we investigated the brain sites at which rhIFN-alpha acts to suppress splenic NK activity in unanesthetized rats implanted unilaterally with a chronic hypothalamic cannula. A microinjection of 200 U of rhIFN-alpha into the medial part of the preoptic hypothalamus reduced NK activity to approximately 60% of control 30 min after the injection. Administration of 50 U of rhIFN-alpha also decreased NK activity to approximately 80%. The injection of 200 U of rhIFN-alpha into other hypothalamic areas (lateral preoptic hypothalamus, ventromedial hypothalamus, lateral hypothalamus, and paraventricular nucleus) had no effect. The medial preoptic hypothalamus-rhIFN-alpha-induced immunosuppression was completely blocked by splenic denervation, but not by adrenalectomy. These results suggest that IFN-alpha suppresses splenic NK activity predominantly through the medial preoptic hypothalamus-sympathetic pathway.
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Yuan, C. S., et W. D. Barber. « Interactions of gastric vagal and peripheral nerves on single neurons of lateral hypothalamus in the cat ». American Journal of Physiology-Gastrointestinal and Liver Physiology 271, no 5 (1 novembre 1996) : G858—G865. http://dx.doi.org/10.1152/ajpgi.1996.271.5.g858.
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Extracellularly recorded unitary responses in the lateral hypothalamus were evaluated in anesthetized cats during electrical stimulation of the gastric branches of the ventral and dorsal vagal trunks, the T9 intercostal nerve, and the common peroneal nerve (L6-S2). These nerves were stimulated with single or paired (10-ms interval) pulses of 300–500 microA for 0.3 ms at a frequency of 0.5 Hz. The latency of the evoked lateral hypothalamic responses after stimulation of the gastric vagal branches (373 +/- 39.8 ms; means +/- SD) was significantly longer than the latencies after intercostal nerve (62 +/- 17.0 ms) or common peroneal nerve (109 +/- 29.3 ms) stimulation. Convergence of gastric vagal input from the proximal stomach and peripheral nerves (PNs) on single neurons in the lateral hypothalamus was observed. Ninety-two percent of the lateral hypothalamic neurons tested that responded to gastric vagal stimulation also received inputs from the T9 intercostal nerve. Seventy-seven percent of the lateral hypothalamic gastric vagally evoked unitary responses received convergent inputs from the intercostal nerve and the common peroneal nerve. A condition-test paradigm was applied to determine the time course of convergent gastric and PN input on single lateral hypothalamic neurons. The test revealed that stimulation of the T9 intercostal nerve had a more pronounced effect than common peroneal nerve stimulation on the lateral hypothalamic neurons that receive gastric vagal input. The results demonstrated that gastric vagal afferent and PN inputs converge onto single lateral hypothalamic neurons and suggested that the central processing of visceral input from the stomach can be substantially affected by peripheral nerve stimulation.
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Gutterman, D. D., A. C. Bonham, G. F. Gebhart, M. L. Marcus et M. J. Brody. « Connections between hypothalamus and medullary reticular formation mediate coronary vasoconstriction ». American Journal of Physiology-Heart and Circulatory Physiology 259, no 3 (1 septembre 1990) : H917—H924. http://dx.doi.org/10.1152/ajpheart.1990.259.3.h917.
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We have recently identified discrete sites within the lateral hypothalamus and medullary reticular formation that, when stimulated electrically, produce neurally mediated coronary vasoconstriction. This study examined whether these sites are part of the same coronary vasomotor pathway. The neuronal tracing dye fast blue was injected in cats into the coronary vasoconstrictor site within medullary reticular formation. Fluorescence microscopy revealed major afferent projections originating from within the same region of midbrain ventrolateral periaqueductal gray that receives projections from lateral hypothalamus. To determine the functional importance of the proposed connections between the hypothalamic and medullary sites, anesthetized cats were prepared for continuous hemodynamic measurements. Constant current electrical stimulation within lateral hypothalamus produced significant increases in heart rate (21 +/- 6%), arterial pressure (11 +/- 3%), and femoral (36 +/- 18%) and coronary resistances (14 +/- 9%) with no change in coronary flow velocity (-1.1 +/- 2.5%). After beta-adrenoreceptor blockade, significantly greater increases in arterial pressure (35 +/- 8%) and coronary resistance (39 +/- 5%) with transient decreases in coronary flow velocity (21 +/- 6%) were seen. Microinjections of lidocaine into the medullary site blocked coronary constriction produced by lateral hypothalamic stimulation (39 +/- 5% increase in coronary resistance to electrical stimulation before and 2.4 +/- 2% increase after lidocaine in medullary reticular formation). These data provide evidence that specific regions of lateral hypothalamus and medullary reticular formation are part of a common central vasomotor projection that mediates coronary vasoconstriction in addition to other hemodynamic effects.
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Yuan, C. S., et W. D. Barber. « Hypothalamic unitary responses to gastric vagal input from the proximal stomach ». American Journal of Physiology-Gastrointestinal and Liver Physiology 262, no 1 (1 janvier 1992) : G74—G80. http://dx.doi.org/10.1152/ajpgi.1992.262.1.g74.
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Gastric vagally evoked extracellular unitary responses were recorded in the hypothalamus of anesthetized cats. The evoked unitary responses were localized in the paraventricular dorsomedial region, ventromedial nucleus, and lateral hypothalamus. The mean latency of the gastric vagally evoked hypothalamic neuronal responses in these three areas ranged from 368 +/- 39.8 to 371 +/- 45.2 (SD) ms. The majority (82%) of the gastric vagally evoked hypothalamic responses consisted of one to five spikes, while the remaining 18% were tonically active units. The vagal effect was inhibitory in 78% of the tonically active hypothalamic units responding to gastric vagal input. Convergence of gastric vagal input on single hypothalamic units from afferents in the dorsal and ventral vagal trunks was observed. Units were identified in the hypothalamus that responded to activation of mechanoreceptors in the proximal stomach by an intragastric balloon. This study provided new direct evidence of the density, localization, and characteristics of neuronal processing of gastric vagal input from the proximal stomach in the hypothalamus. The reciprocal connections between these areas of the hypothalamus and nucleus tractus solitarius in the caudal brain stem suggest that the hypothalamus may serve an important role in modulating the input of primary vagal afferent input from the proximal stomach.
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Shimizu, Toru, Kevin Cox, Harvey J. Karten et Luiz R. G. Britto. « Cholera toxin mapping of retinal projections in pigeons (Columba livia), with emphasis on retinohypothalamic connections ». Visual Neuroscience 11, no 3 (mai 1994) : 441–46. http://dx.doi.org/10.1017/s0952523800002376.
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AbstractAnterograde transport of cholera toxin subunit B (CTb) was used to study the retinal projections in birds, with an emphasis on retinohypothalamic connections. Pigeons (Columba livia) were deeply anesthetized and received unilateral intraocular injections of CTb. In addition to known contralateral retinorecipient regions, CTb-immunoreactive fibers and presumptive terminals were found in several ipsilateral regions, such as the nucleus of the basal optic root, ventral lateral geniculate nucleus, intergeniculate leaflet, nucleus lateralis anterior, area pretectalis, and nucleus pretectalis diffusus. In the hypothalamus, CTb-immunoreactive fibers were observed in at least two contralateral cell groups, a medial hypothalamic retinorecipient nucleus, and a lateral hypothalamic retinorecipient nucleus. To compare retinorecipient hypothalamic nuclei in pigeons with the mammalian suprachiasmatic nucleus, double-label experiments were conducted to study the existence of neurophysin-like immunoreactivity in the retinorecipient avian hypothalamus. The results showed that only cell bodies in the medial hypothalamic nucleus contained neurophysin-like immunoreactivity. The results demonstrate CTb to be a sensitive anterograde tracer and provide further anatomical information on the avian equivalent of the mammalian suprachiasmatic nucleus.
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Bonham, A. C., D. D. Gutterman, J. M. Arthur, M. L. Marcus, G. F. Gebhart et M. J. Brody. « Electrical stimulation in perifornical lateral hypothalamus decreases coronary blood flow in cats ». American Journal of Physiology-Heart and Circulatory Physiology 252, no 3 (1 mars 1987) : H474—H484. http://dx.doi.org/10.1152/ajpheart.1987.252.3.h474.
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Based on evidence implicating the central nervous system in the regulation of coronary vascular resistance and the knowledge that the hypothalamus is a central site for integration of cardiovascular control, studies were undertaken to determine if electrical stimulation in the hypothalamus produced coronary vasoconstriction. In anesthetized cats, following beta-adrenergic receptor blockade, stimulation in perifornical lateral hypothalamus produced a transient decrease in coronary blood flow velocity (30 +/- 5%), a small pressor effect (7 +/- 2 mmHg), and an initial decrease in hindquarter blood flow velocity (51 +/- 5%). The decrease in coronary flow velocity, which had an onset latency of 1-3 s and a duration of 5-15 s, was abolished by ipsilateral stellate ganglionectomy and by intravenous and intracoronary prazosin. The coronary vasoconstriction produced by hypothalamic stimulation was not different from that produced by cardioaccelerator nerve stimulation. These results suggest that electrical stimulation of a hypothalamic site produces an alpha-adrenergic receptor-mediated decrease in coronary blood flow that is unmasked by beta-adrenergic receptor blockade, requires the integrity of ipsilateral cardiac sympathetic innervation, and mimics the coronary response to cardioaccelerator nerve stimulation.
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Meylakh, Noemi, Kasia K. Marciszewski, Flavia Di Pietro, Vaughan G. Macefield, Paul M. Macey et Luke A. Henderson. « Altered regional cerebral blood flow and hypothalamic connectivity immediately prior to a migraine headache ». Cephalalgia 40, no 5 (12 mars 2020) : 448–60. http://dx.doi.org/10.1177/0333102420911623.
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Background There is evidence of altered resting hypothalamic activity patterns and connectivity prior to a migraine, however it remains unknown if these changes are driven by changes in overall hypothalamic activity levels. If they are, it would corroborate the idea that changes in hypothalamic function result in alteration in brainstem pain processing sensitivity, which either triggers a migraine headache itself or allows an external trigger to initiate a migraine headache. We hypothesise that hypothalamic activity increases immediately prior to a migraine headache and this is accompanied by altered functional connectivity to pain processing sites in the brainstem. Methods In 34 migraineurs and 26 healthy controls, we collected a series comprising 108 pseudo-continuous arterial spin labelling images and 180 gradient-echo echo planar resting-state functional magnetic resonance volumes to measure resting regional cerebral blood flow and functional connectivity respectively. Images were pre-processed and analysed using custom SPM12 and Matlab software. Results Our results reflect that immediately prior to a migraine headache, resting regional cerebral blood flow decreases in the lateral hypothalamus. In addition, resting functional connectivity strength decreased between the lateral hypothalamus and important regions of the pain processing pathway, such as the midbrain periaqueductal gray, dorsal pons, rostral ventromedial medulla and cingulate cortex, only during this critical period before a migraine headache. Conclusion These data suggest altered hypothalamic function and connectivity in the period immediately prior to a migraine headache and supports the hypothesis that the hypothalamus is involved in migraine initiation.
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Mondal, Muhtashan S., Masamitsu Nakazato et Shigeru Matsukura. « Orexins (hypocretins) : novel hypothalamic peptides with divergent functions ». Biochemistry and Cell Biology 78, no 3 (2 avril 2000) : 299–305. http://dx.doi.org/10.1139/o00-022.
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The hypothalamus is the most important region in the control of food intake and body weight. The ventromedial "satiety center" and lateral hypothalamic "feeding center" have been implicated in the regulation of feeding and energy homeostasis by various studies of brain lesions. The discovery of orexin peptides, whose neurons are localized in the lateral hypothalamus and adjacent areas, has given us new insight into the regulation of feeding. Dense fiber projections are found throughout the brain, especially in the raphe nucleus, locus coeruleus, paraventricular thalamic nucleus, arcuate nucleus, and central gray. Orexins mainly stimulate food intake, but by the virtue of wide immunoreactive projections throughout the brain and spinal cord, orexins interact with various neuronal pathways to potentate divergent functions. In this review, we summarize recent progress in the physiological, neuroanatomical, and molecular studies of the novel neuropeptide orexins (hypocretins).Key words: orexins (hypocretins), hypothalamus, lateral hypothalamus, feeding behavior, energy homeostasis, neurons.
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Ishii, Yuko, et Sebastien G. Bouret. « Embryonic Birthdate of Hypothalamic Leptin-Activated Neurons in Mice ». Endocrinology 153, no 8 (23 mai 2012) : 3657–67. http://dx.doi.org/10.1210/en.2012-1328.
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The hypothalamus plays a critical role in the regulation of energy balance. Neuroanatomical and mouse genetic data have defined a core circuitry in the hypothalamus that mediates many of the effects of leptin on feeding and energy balance regulation. The present study used 5-bromo-2′-deoxyuridine (a marker of dividing cells) and a neuronal marker to systematically examine neurogenesis in the mouse embryonic hypothalamus, particularly the birth of neurons that relay leptin signaling. The vast majority of neurons in hypothalamic nuclei known to control energy balance is generated between embryonic days (E) 12 and E16, with a sharp peak of neurogenesis occurring on E12. Neurons in the dorsomedial and paraventricular nuclei and the lateral hypothalamic area are born between E12 and E14. The arcuate and ventromedial nuclei exhibit a relatively longer neurogenic period. Many neurons in these nuclei are born on E12, but some neurons are generated as late as E16. We also examined the birth of leptin-activated cells by coupling the 5-bromo-2′-deoxyuridine staining with cFos immunohistochemistry. Remarkably, the majority of leptin-activated cells in the adult hypothalamus were also born during a discrete developmental window on E12. These results provide new insight into the development of hypothalamic neurons that control feeding and identify important developmental periods when alterations in the intrauterine environment may affect hypothalamic neurogenesis and produce long-term consequences on hypothalamic cell numbers.
Thèses sur le sujet "Lateral hypothalamu"
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Kosse, C. L. « Functional properties of GAD65 neurons in the lateral hypothalamus ». Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10044863/.
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The brain’s ability to sense energy levels and adjust behaviour accordingly is vital for survival in mammals. The lateral hypothalamus (LH), which contains energy-spending (orexin) and energy-conserving melanin-concentrating hormone (MCH) neurons, is thought to be the brain’s master energy sensor and generator of motivated behaviour. Recently, other classes of non-MCH, non-orexin neurons, such as vesicular GABA transporter (VGAT) and glutamic acid decarboxylase 65 (GAD65) expressing neurons, have been discovered in the LH. VGATLH neurons have been shown to be essential for appetitive and consummatory behaviour. However, the properties and behavioural roles of GAD65LH neurons remain unclear, and are the focus of this thesis. The thesis’ three parts examine cellular, circuit, and behavioural roles of GAD65LH neurons. Firstly, whole cell patch clamping was used to determine firing responses of GAD65LH neurons to injections of oscillatory input currents. GAD65LH neurons were found to have similar frequency-preferences of firing resonance to those of VGAT and MCH neurons, whilst orexin neurons showed a different, “high frequency inhibited” frequency-preference profile. Moreover, histochemistry was employed to characterise GAD65LH neurons further by quantifying their overlap with other GABAergic LH cell types. It was found that GAD65LH neurons overlapped only partially with VGATLH neurons, and that neuropeptide Y (NPY) and leptin receptor (LepRb) expressing neurons were largely distinct from GAD65LH cells. Secondly, cell-type specific channelrhodopsin-assisted circuit mapping was used to probe up- and downstream functional targets of GAD65LH neurons. It was found that GAD65LH neurons were excited by orexin neurons and inhibited by VGATLH neurons, and that they preferentially inhibited MCHLH and NPYLH neurons. Finally, chemogenetic excitation or inhibition of GAD65LH cell activity was used to investigate the role of these cells in behaviour. It was found that GAD65LH neurons were weight-loss-promoting, and essential and sufficient for normal locomotor activity. Overall, these results define and characterise a new cellular network component in LH function.
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Carus-Cadavieco, Marta. « Coordination of innate behaviors by GABAergic cells in lateral hypothalamus ». Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19135.
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Der laterale Hypothalamus (LH) reguliert angeborene Verhaltensweisen. Ob und wie die Koordination von hypothalamischen Neuronengruppen Verhaltensübergänge reguliert, blieb jedoch unbekannt. In dieser Arbeit wurde Optogenetik mit neuronalen Ableitungen in verhaltenden Mäusen kombiniert. LHVgat Neurone erhöhten ihre Aktivitätsrate während Übergängen vom NREM-Schlaf zum Wachzustand. LHVgat Zellen projizieren zum Nucleus reticularis des Thalamus (RTN). Optogenetische Aktivierung von Vgat Ausgängen im RTN führte eine starke, frequenzabhängige Inhibierung von RTN Zellen herbei und replizierte Verhaltenszustands-abhängige Aktivitätsraten in RTN Neuronen. Ableitungen von LH Neuronen während Umgebungserkundung ergaben, dass 65% der LH Neurone ihre Aktivitätsrate erhöhten, wenn das Tier began sich fortzubewegen. 'Top-down’ Vorderhirn Innervation des LH erfolgt größtenteils durch Signale ausgehend vom lateralen Septums (LS). Während spontaner Umgebungserkundung und freiem Zugang zu Futter wiesen der LH und das LS Gamma-Oszillationen (30-90 Hz) auf, welche neuronale Aktivität innerhalb und zwischen diesen beiden Gehirnregionen synchronisierten. Optogenetische Stimulation von Somatostatin-positiven GABAergen Projektionen zum LH mit Gamma-Frequenz förderte die Nahrungssuche und erhöhte die Wahrscheinlichkeit des Betretens der Nahrungszone. Inhibitorische Signale des LS bewirkten eine Unterteilung der LH Neurone: entsprechend ihrer Aktivität im Bezug zur Nahrungsstelle wurden sie während bestimmter Phasen der Gamma-Oszillation aktiviert. Dabei führte optogenetische Stimulation von LS-LH Neuronen mit Gamma-Frequenz keine Veränderung bei der Nahrungsaufnahme selbst herbei. Insgesamt liefert diese Arbeit neue Einsichten über die Funktion der neuronalen Netzwerke des LH, welche durch Signalgebung mit unterschiedlichen Zeitskalen über die Koordination mit vor- und nachgeschalteten neuronalen Netzwerken Übergange zwischen verschiedenen angeborenen Verhaltensweisen regeln.Lateral hypothalamus (LH) is crucial for regulation of innate behaviors. However, it remained unknown whether and how temporal coordination of hypothalamic neuronal populations regulates behavioral transitions. This work combined optogenetics with neuronal recordings in behaving mice. LHVgat cells were optogenetically identified. LHVgat neurons increased firing rates upon transitions from non-REM (NREM) sleep to wakefulness, and their optogenetic stimulation during NREM sleep induced a fast transition to wakefulness. LHVgat cells project to the reticular thalamic nucleus (RTN). Optogenetic activation of LHVgat terminals in the RTN exerted a strong frequency-dependent inhibition of RTN cells and replicated state-dependent changes in RTN neurons activity. Recordings of LH neurons during exploration revealed that 65% of LH neurons increased their activity upon the onset of locomotion. Top-down forebrain innervation of LH is provided, to a great extent, by inhibitory inputs from the lateral septum (LS). During spontaneous exploration in a free-feeding model, LS and LH displayed prominent gamma oscillations (30-90 Hz) which entrained neuronal activity within and across the two regions. Optogenetic gamma-frequency stimulation of somatostatin-positive GABAergic projections to LH facilitated food-seeking, and increased the probability of entering the food zone. LS inhibitory input enabled separate signaling by LH neurons according to their feeding-related activity, making them fire at distinct phases of the gamma oscillation. In contrast to increased food intake during optogenetic stimulation of LHVgat cells, food intake during gamma-rhythmic LS-LH stimulation was not changed. Overall this works provides new insight into the function of LH circuitry, that employs signalling at different time scales, which, in coordination with upstream and downstream circuits, regulates transitions between innate behaviors.
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Boucher-Thrasher, Annette. « Evidence for anatomical connectivity between lateral hypothalamic and lateral preoptic area brain stimulation sites ». Thesis, University of Ottawa (Canada), 1987. http://hdl.handle.net/10393/5246.
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Scollon, Jennifer Margaret. « The function of the lateral hypothalamus with regard to gustatory and reward related processes ». Thesis, University of St Andrews, 1999. http://hdl.handle.net/10023/14701.
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The lateral hypothalamus (LH) has been shown to be involved in consummatory behaviour by a number of different experimental techniques including behavioural and electrophysiological methods. Lesion studies indicate that loss of the LH does not significantly alter normal feeding and drinking in the home cage, responding to food and water deprivation or responding to glucose or salt adulteration of the diet. However, when injected with dehydrating, dipsogenic or glucoprivic agents, the so called needle challenges, LH lesioned rats failed to respond as sham lesioned rats. This is despite the fact that the injections described induced the same deficits in homeostasis as food and water deprivation. Both sets of challenges are cued by internal visceral signals but only deprivation has additional environmental cues; animals are aware that their food or water are missing and may even anticipate its return. These different types of cues may be conveyed by different neural pathways and it has been proposed that lesioning the LH removes a pathway whereby visceral signals reach higher neural structures thus accounting for why LH lesioned rats responded appropriately to deprivation but not needle challenges. The present study examined the hypothesis that the LH acts as a gateway for signals concerning internal state to reach structures involved in behavioural planning and action. This was tested by the use of tests known to be susceptible to damage or change in the paraventricular system, responsible for monitoring the internal milieu, and frontostriatal systems responsible for behavioural planning and execution. The functions known to be dependent on the paraventricular system which were tested were conditioned taste aversion, benzodiazepine induced hyperphagia and taste perception but no deficits were found in responding in any of these procedures as a result of lesioning the LH. The functions known to be dependent on frontostriatal systems that were examined with LH lesioned rats were conditioned reinforcement and conditioned place preference but again few deficits were found. Hence, the present study failed to provide evidence to substantiate the hypothesis that the LH stands as an interface between the paraventricular system and frontostriatal systems. However, it did provide evidence that lesioning the LH induces deficits in consummatory responses dependent on the circumstances of the tests.
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Oh, Jeremy Jaehwan. « Posterior lateral hypothalamus stimulation confirms brain reward site stimulation-induced hyperalgesia ». Thesis, Boston University, 2012. https://hdl.handle.net/2144/12548.
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Thesis (M.A.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.Pain is known as one of the most important physical sensations that contribute to animal survival. Kornetsky and colleagues (201 0) established mesencephalic reticular formation (MRF) and midbrain forebrain bundle (MFB) thresholds separately and found that simultaneous stimulation of the sites significantly lowered MRF escape thresholds. They also found that the simultaneous stimulation of the sites eliminated the analgesic effect--that is, raising the MRF threshold--of morphine. In an effort to better understand the interaction between rewarding brain stimulation and nociceptive pain, this study expands upon the previous experiment by implanting an electrode in the ventral tegmental area (VTA). However, during the post-mortem histological review, it was found that the rewarding electrodes were implanted in the posterior lateral hypothalamus (PLH), not in the VTA. Our overall results of this experiment demonstrate similar findings as the previous study (Kornetsky et al., 2010). The simultaneous stimulation of the MRF and PLH significantly lowered MRF escape thresholds and eliminated the analgesic effects of morphine. A very low, subthreshold intensity of stimulation to the PLH yielded significantly increased sensitivity to MRF stimulation. Furthermore, the results show that morphine did not lower BSE threshold, when the MRF was simultaneously stimulated with the PLH. An examination of the rewarding electrode placements found in the simultaneous MRF and MFB stimulation experiment by Kornetsky and colleagues (2010) also show rewarding electrode in the PLH, which corroborates with the results in this experiment.
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Morutto, Sara Lidia. « Role of the perifornical region of the lateral hypothalamus in appetitive conditioning ». Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288040.
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Venner, Anne. « The electrical activity of lateral hypothalamic neurons and its regulation by nutrients and ethanol ». Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610286.
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Nieh, Edward H. (Edward Horng-An). « Lateral hypothalamic control of motivated behaviors through the midbrain dopamine system ». Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/106440.
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Thesis: Ph. D. in Neuroscience, Massachusetts Institute of Technology, Department of Brain and Cognitive Sciences, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 209-231).
The lateral hypothalamus and ventral tegmental area are two brain regions that have long been known to be involved in processing reward and the control of feeding behaviors. We continue work in this area by identifying the functional connectivity between these two regions, providing evidence that LH neurons projecting to the VTA encode conditioned responses, while LH neurons innervated by the VTA encode conditioned and unconditioned stimuli. Activation of the LH-VTA projection can increase compulsive sugar seeking, while inhibition of the projection can suppress this behavior without altering normal feeding due to hunger. We can separate this projection into the GABAergic and glutamatergic components, and we show that the GABAergic component plays a role in promoting feeding and social interaction by increasing motivation for consummatory behaviors, while the glutamatergic component largely plays a role in the suppression of these behaviors. Finally, we show that activation of the GABAergic component causes dopamine release downstream in the nucleus accumbens via disinhibition of VTA dopamine neurons through VTA GABA neurons. Together, these experiments have profoundly elucidated the functional roles of the individual circuit components of the greater mesolimbic dopamine system and provided potential targets for therapeutic intervention of overeating disorders and obesity..
by Edward H. Nieh.
Ph. D. in Neuroscience
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Martianova, Ekaterina. « The role of the lateral hypothalamic neural outputs in motivated behaviour ». Doctoral thesis, Université Laval, 2020. http://hdl.handle.net/20.500.11794/67902.
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Comprendre comment le cerveau traite l’information est l’une des questions les plus intrigantes auxquelles les neurosciences modernes sont confrontées. L’étude actuelle vise à caractériser comment l’hypothalamus latéral (HL) traite l’information vers des cibles cérébrales en aval afin de guider des réponses comportementales appropriées. L’HL est une zone du cerveau qui régule des comportements vitaux tels que les fonctions autonomes et endocriniennes, l’équilibre homéostatique, la régulation du métabolisme et les cycles veille-sommeil. De plus, des études récentes soulignent son importance dans le traitement de l’aversion et de la récompense. L’HL envoie des projections neurales à de nombreux noyaux cérébraux connus pour traiter des signaux qui jouent un rôle important pour guider et orchestrer des réponses comportementales appropriées. Des expériences visant a déterminer les connections afferentes et efférentesde l’HL ont démontré que trois noyaux cérébraux importants reçoivent des projections importantes de l’HL. Il s’agit de l’habenula latéral (HbL), de l’aire tegmentale ventrale (ATV) et du noyau raphe dorsal (NRD). L’HbL est le principal centre de déception du cerveau : son activité augmente spécifiquement lorsqu’un animal est soumis à des stimuli aversifs ou en l’absence de récompenses attendues, jouant un rôle important dans la signalisation d’une erreur de prédiction de punition. L’ATV dopaminergique est le principal centre de récompense du cerveau. Il joue un rôle important dans l’encodage de la valeur des récompenses, l’apprentissage du renforcement et la motivation. Le NRD est le principal centre de sérotonine jouant un rôle important dans le traitement des émotions et les réponses adaptatives. Pour examiner spécifiquement la contribution des sorties neuronales de l’HL chez les souris en mouvement libre, nous avons utilisé une technique d’imagerie avancée du calcium – système de photométrie à fibres. La photométrie à fibres est une approche puissante qui combine des indicateurs de calcium codés génétiquement et des fibres optiques multimodes pour monitorer l’activité neuronale chez les animaux en mouvement libre, ce qui est essentiel pour comprendre comment des groupes spécifiques de neurones sont impliqués dans le contrôle ou la réponse à une action ou à un stimulus. Dans le premier chapitre, je présente un protocole qui a été développé pour une détection fiable des signaux de calcium à l’aide d’un système de photométrie multifibre. Le protocole détaille les composantes d’un système de photométrie multifibres, la méthode pour accéder aux structures profondes du cerveau pour délivrer et collecter la lumière, et une méthode pour prendre en compte les artefacts de mouvement avant et pendant les enregistrements. En outre,je présente un algorithme de traitement des signaux enregistrés qui tient compte des sources communes d’artefacts qui sont inévitables pendant les enregistrements. Dans le deuxième chapitre, je présente les résultats de l’étude du rôle fonctionnel de trois sorties neurales de l’HL vers le NRD, l’ATV et l’HbL. En utilisant le protocole décrit dans le premier chapitre, l’activité dans les voies HL→NRD, HL→ ATV et HL→HbL a été simultanément enregistrée lors de réponses comportamentales dans des contextes d’aversion et de récompense. Nous avons constaté que l’activité à ces trois sorties neurales de l’HL augmentait avec des stimuli et des signaux prédictifs de stimuli aversifs. L’activité neuronale augmente également lors des réponses comportementales motivées spontanées et diminue lors de l’immobilité comportementale. L’activation optogénétique indépendante des terminaisons axonales de l’HL au niveau de l’HbL, l’ATV ou le NRD était suffisante pour augmenter la mobilité, mais a eu des effets différents dans d’autres tests comportementaux. Dans l’ensemble, nous proposons que l’HL envoie des signaux complémentaires aux cibles en aval pour traiter les informations engagées pour promouvoir des comportements motivés. En annexe, je présente un ensemble d’analyse de données python qui a été développé pour traiter tous les enregistrements de photométrie à fibre optique présentés dans l’étude actuelle. Cet ensemble permet de combiner, de stocker et d’analyser les enregistrements de plusieurs souris, essais et différentes expériences avec diverses mesures, événements comportementaux et stimuli de manière standardisée.Understanding how brain processes information is the one of the most intriguing questions that modern neuroscience faces. The current study aims to characterize how the lateral hypothalamus (LH) processes information to downstream brain targets to guide proper behavioral responses. The LH is a brain area that regulates vital behaviors such as autonomic and endocrine functions, homeostatic balance, regulation of metabolism, and sleep-wake cycles. Moreover, recent studies point out its importance in aversive and appetitive processing. The LH sends neural projections to many brain nuclei known to process signals that play important roles to guide and orchestrate proper behavior responses. Tracing experiments demonstrated that three important brain nuclei receive significant inputs from the LH, the lateral habenula (LHb), the ventral tegmental area (VTA), and the dorsal raphe nucleus (DRN). The LHb is the main disappointment center of the brain: its activity specifically increases when an animalis presented an aversive stimuli or in the absence of expected rewards, playing an important role in signaling punishment prediction error. The dopaminergic VTA is the main brain reward center. It plays important roles in reward-value encoding, reinforcement learning and motivation. The DRN is the main serotonin center playing and important role in emotion processing and adaptive responses. To specifically examine the contribution of LH neural outputs in freely moving mice, we used an advanced calcium imaging technique – fiber photometry system. Fiber photometry is a powerful approach that combines genetically encoded calcium indicators and multimode optical fibers to monitor neuronal activity in freely moving animals, which is critical to understand how specific groups of neurons play in directing or responding to an action or a stimulus. In the first chapter, I present a protocol that was developed for reliable detection of calcium signal using a camera-based multi-fiber photometry system. The protocol details the components of a multi-fiber photometry system, a method to access deep brain structures to deliverand collect light, and a method to account for motion artifacts before and during recordings. Additionally, I present an algorithm for processing of recorded signals that accounts common sources of artefacts that are inevitable during recordings. In the second chapter, I present results of the investigation of the functional role of three LH outputs to the DRN, VTA, and LHb. Using the protocol described in the first chapter, activity in the LH→DRN, LH→ VTA and LH→LHb pathways were simultaneously recorded during motivated responses in aversive and appetitive contexts. We found that these three LH neural outputs increased activity with aversive stimuli and cues predicting them. The neural activity also increased at onsets of spontaneous motivated behavior responses and decreased duringbehavioral immobility. Independent optogenetic activation of axon terminals in LHb, VTA,or DRN was sufficient to increase mobility, but had different effects in other behavioural tests. Altogether, we propose that LH sends complementary signals to the downstream targets to process information engaged in motivated behaviors. In the annex, I present a data analysis python package that was developed to process all fiber photometry recordings presented in the current study. The package allow to combine, store, and analyze recordings from multiple mice, trials, and different experiments with various measurements, behavioural events, and stimuli in a standardized way.
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Clark, Judith. « Examinations of the nature of the deficits induced by n-methyl-D-aspartic acid lesions of the rat lateral hypothalamus ». Thesis, University of St Andrews, 1990. http://hdl.handle.net/10023/14703.
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The lateral hypothalamic syndrome of aphagia, adipsia akinesia and sensorimotor impairments induced by electrolytic lesions of the lateral hypothalamus (LH) has been suggested to be due to the destruction of two components of a single system controlling feeding and drinking behaviour. While the "motor" component has been attributed to disruption of dopaminergic fibres, it has been suggested that destruction of intrinsic LH neurones induces a "motivational" deficit. The nature of this motivational deficit was investigated using the excitotoxin N-methyl-d~aspartic acid (NMDA) to lesion cell bodies and leave fibres of passage intact. Such lesions induced temporary reductions in body weight, food and water intake and residual deficits in response to some physiological challenges. Most animals recovered food and water intake and body weight gain after a short period of time. It was shown that LH lesioned rats were able to perceive and respond to the palatability of food/fluid; they responded physiologically to intracellular dehydration caused by hypertonic saline injections, although they did not respond behaviourally; they responded as controls to a battery of long-term, "positive" physiological challenges, but not to short-term, "negative" ones; and they displayed increased rate of development of schedule-induced polydipsia and tail pinch-induced eating, demonstrating that they had no motor impairments and that they did not have an "activational" deficit. These results indicate that the LH cannot be regarded as a feeding or drinking "centre" and that the motivational deficit following lesions of the LH is of a very complex nature. The implications of these data for the function of the LH are discussed in relation to electrophysiological and anatomical studies.
Livres sur le sujet "Lateral hypothalamu"
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Kurt, Gizem, Hillary L. Woodworth, Gina M. Leinninger, D. Neil Granger et Joey P. Granger. Lateral Hypothalamic Control of Energy Balance. Morgan & Claypool Life Science Publishers, 2017.
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Kurt, Gizem, Hillary L. Woodworth, Gina M. Leinninger, D. Neil Granger et Joey P. Granger. Lateral Hypothalamic Control of Energy Balance. Morgan & Claypool Life Science Publishers, 2017.
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Kurt, Gizem, Hillary L. Woodworth, Gina M. Leinninger, D. Neil Granger et Joey P. Granger. Lateral Hypothalamic Control of Energy Balance. Morgan & Claypool Life Science Publishers, 2017.
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Tononi, Giulio, et Chiara Cirelli. The Neurobiology of Sleep. Sous la direction de Dennis S. Charney, Eric J. Nestler, Pamela Sklar et Joseph D. Buxbaum. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780190681425.003.0011.
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Sleep is required for health and well-being, and consumes roughly one-third of a human’s lifetime, yet its functions remain incompletely understood. This chapter provides an overview of so-called sleep architecture—the stages and cycles that characterize sleep, including rapid eye movement (REM) and non-REM periods. Also discussed are the numerous regions of brain and neurotransmitters that control the induction of sleep, the transitions between REM and non-REM sleep cycles, and wakefulness. Key brain systems include GABAergic neurons in the pre-optic area, the neuropeptide orexin in lateral hypothalamic neurons, histaminergic neurons in the hypothalamus, monoaminergic (norepinephrine and serotonin) and acetylcholinergic nuclei in the brainstem, and the brain’s adenosine system, all of which work in integrated circuits to control sleep and wakefulness. Overlaid on sleep-wake cycles are circadian rhythms, and the crucial role played by the suprachiasmatic nucleus in entraining such rhythms to environmental light.
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Venner, Anne, et Patrick M. Fuller. An overview of sleep–wake circuitry. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198778240.003.0005.
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How and when we wake and sleep are under the control of incredibly complex neural circuitry, consisting of neuronal populations (or nodes), neurotransmitters, and pathways that form orchestrated wake- or sleep-promoting networks. When any aspect of this neural circuitry is impaired (e.g. disease) or altered by external factors (e.g. stress), sleep and wake can be disrupted, sometimes quite profoundly. As one example, selective loss of orexin neurons in the lateral hypothalamus results in the sleep disorder narcolepsy. While our understanding of how discrete circuit elements in the brain work together to regulate wake and sleep remains incomplete, the relatively recent development of genetically driven tools and techniques has enabled a far more detailed understanding of the functional and structural basis of this circuitry. In this chapter, we review the current state of our understanding of the brain circuitry regulating sleep and wake, including how disruption of discrete circuit elements underlies a myriad of sleep- and wake-disorders.
Chapitres de livres sur le sujet "Lateral hypothalamu"
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Kondoh, Takashi, Tentcho Voynikov, Eiichi Tabuchi, Takashi Yokawa, Taketoshi Ono et Kunio Torii. « Responses of Lateral Hypothalamic Neurons in Lysine-Deficient Rats ». Dans Olfaction and Taste XI, 534–35. Tokyo : Springer Japan, 1994. http://dx.doi.org/10.1007/978-4-431-68355-1_222.
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Broberger, Christian, et Tomas Hökfelt. « Transmitter-Identified Neurons and Afferent Innervation of the Lateral Hypothalamic Area ». Dans Hypocretins, 95–120. Boston, MA : Springer US, 2005. http://dx.doi.org/10.1007/0-387-25446-3_7.
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Saper, Clifford B. « The Prehistory of Orexin/Hypocretin and Melanin-Concentrating Hormone Neurons of the Lateral Hypothalamus ». Dans Narcolepsy, 205–9. New York, NY : Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-8390-9_18.
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Ono, Taketoshi, Masaji Fukuda, Hisao Nishijo et Kiyomi Nakamura. « Plasticity in Inferotemporal Cortex-Amygdala-Lateral Hypothalamus Axis during Operant Behavior of the Monkey ». Dans Cellular Mechanisms of Conditioning and Behavioral Plasticity, 149–59. Boston, MA : Springer US, 1988. http://dx.doi.org/10.1007/978-1-4757-9610-0_15.
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Tabuchi, E., T. Kondoh, T. Voynikov, T. Yokawa, T. Ono et K. Torii. « Lateral Hypothalamic Neuron Response to Application of Amino Acids in Different Nutritive Conditions ». Dans Olfaction and Taste XI, 536. Tokyo : Springer Japan, 1994. http://dx.doi.org/10.1007/978-4-431-68355-1_223.
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Arita, H., I. Kita et M. Sakamoto. « Two Distinct Descending Inputs to the Cricothyroid Motoneuron in the Medulla Originating from the Amygdala and the Lateral Hypothalamic Area ». Dans Advances in Experimental Medicine and Biology, 53–58. Boston, MA : Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-1933-1_10.
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Bernabeu, Ignacio, Monica Marazuela et Felipe F. Casanueva. « General concepts of hypothalamus-pituitary anatomy ». Dans Oxford Textbook of Endocrinology and Diabetes, 71–81. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199235292.003.2004.
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The hypothalamus is the part of the diencephalon associated with visceral, autonomic, endocrine, affective, and emotional behaviour. It lies in the walls of the third ventricle, separated from the thalamus by the hypothalamic sulcus. The rostral boundary of the hypothalamus is roughly defined as a line through the optic chiasm, lamina terminalis, and anterior commissure, and an imaginary line extending from the posterior commissure to the caudal limit of the mamillary body represents the caudal boundary. Externally, the hypothalamus is bounded rostrally by the optic chiasm, laterally by the optic tract, and posteriorly by the mamillary bodies. Dorsolaterally, the hypothalamus extends to the medial edge of the internal capsule (Fig. 2.1.1) (1). The complicated anatomy of this area of the central nervous system (CNS) is the reason why, for a long time, little was known about its anatomical organization and functional significance. Even though the anatomy of the hypothalamus is well established it does not form a well-circumscribed region. On the contrary, it is continuous with the surrounding parts of the CNS: rostrally, with the septal area of the telencephalon and anterior perforating substance; anterolaterally with the substantia innominata; and caudally with the central grey matter and the tegmentum of the mesencephalon. The ventral portion of the hypothalamus and the third ventricular recess form the infundibulum, which represents the most proximal part of the neurohypophysis. A bulging region posterior to the infundibulum is the tuber cinereum, and the zone that forms the floor of the third ventricle is called the median eminence. The median eminence represents the final point of convergence of pathways from the CNS on the peripheral endocrine system and it is supplied by primary capillaries of the hypophyseal portal vessels. The median eminence is the anatomical interface between the brain and the anterior pituitary. Ependymal cells lining the floor of the third ventricle have processes that traverse the width of the median eminence and terminate near the portal perivascular space; these cells, called tanycytes, provide a structural and functional link between the cerebrospinal fluid (CSF) and the perivascular space of the pituitary portal vessels. The conspicuous landmarks of the ventral surface of the brain can be used to divide the hypothalamus into three parts: anterior (preoptic and supraoptic regions), middle (tuberal region), and caudal (mamillary region). Each half of the hypothalamus is also divided into a medial and lateral zone. The medial zone contains the so-called cell-rich areas with well-defined nuclei. The scattered cells of the lateral hypothalamic area have long overlapping dendrites, similar to the cells of the reticular formation. Some of these neurons send axons directly to the cerebral cortex and others project down into the brainstem and spinal cord.
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« Lateral tuberal nucleus ». Dans The Human Hypothalamus - Middle and Posterior Region, 339. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-12-820107-7.09999-7.
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Ahmed, Rebekah M., Frederik Steyn et Luc Dupuis. « Hypothalamus and weight loss in amyotrophic lateral sclerosis ». Dans The Human Hypothalamus - Middle and Posterior Region, 327–38. Elsevier, 2021. http://dx.doi.org/10.1016/b978-0-12-820107-7.00020-3.
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Ojeda, Sergio R. « The Anterior Pituitary and Hypothalamus ». Dans Textbook of Endocrine Physiology. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199744121.003.0008.
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The hypothalamic-pituitary complex represents the core of the neuroendocrine system. The hypothalamus is composed of a diversity of neurosecretory cells arranged in groups, which secrete their products either into the portal blood system that connects the hypothalamus to the adenohypophysis (see later) or directly into the general circulation after storage in the neurohypophysis (see Chapter 6). Because of the nature of their actions, the hypothalamic hormones are classified as releasing or inhibiting hormones. The hypothalamic hormones delivered to the portal blood system are transported to the adenohypophysis, where they stimulate or inhibit the synthesis and secretion of different trophic hormones. In turn, these hormones regulate gonadal, thyroid, and adrenal function, in addition to lactation, bodily growth, and somatic development. No attempt will be made in this chapter to cover the actions of the different pituitary trophic hormones on their target glands, because they are discussed in detail in other chapters. An exception to this is growth hormone (GH). Although Chapter 11 considers several aspects of the control and actions of GH, a broader discussion of its physiological actions will be presented here because GH is the only anterior pituitary hormone that does not have a clear-cut target gland. The pituitary gland has two parts: the neurohypophysis, of neural origin (see Chapter 6), and the adenohypophysis, of ectodermal origin. In embryonic development, an evagination from the roof of the pharynx pushes dorsally to reach a ventrally directed evagination from the base of the diencephalon. The dorsally projecting evagination, known as Rathke’s pouch , forms the adenohypophysis, whereas the ventrally directed evagination of neural tissue forms the neurohypophysis. The neurohypophysis has three parts: the median eminence, the infundibular stem, and the neural lobe itself. The median eminence represents the intrahypothalamic portion and lies just ventral to the floor of the third ventricle protruding slightly in the midline. The main part of the neurohypophysis, the neural lobe, is connected to the median eminence by the infundibular stem.
Actes de conférences sur le sujet "Lateral hypothalamu"
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Henningsen, Jo B., Barbara Baldo, Maria Björkqvist et Åsa Petersén. « A54 The role of excitotoxicity for neuropathology in the lateral hypothalamus in mouse models of huntington disease ». Dans EHDN 2018 Plenary Meeting, Vienna, Austria, Programme and Abstracts. BMJ Publishing Group Ltd, 2018. http://dx.doi.org/10.1136/jnnp-2018-ehdn.52.
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Oliveira, Jefferson Borges de, Caroline Berthier Zanin, Gustavo Carreira Henriques, Maiévi Liston, Rafael Glória Zatta, Rodrigo de Faria Martins et Tatiana Pizzolotto Bruch. « Pallister-Hall Syndrome - case report ». Dans XIII Congresso Paulista de Neurologia. Zeppelini Editorial e Comunicação, 2021. http://dx.doi.org/10.5327/1516-3180.575.
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In 1980, Hall et all described a syndrome characterized by “hamartoblastoma”, hypopituitarism, unperfurated anus, polydactyly postaxial and numerous visceral anomalies, today known as Pallister-Hall Syndrome. On the study, Hall et all reported six cases of children with that malformation syndrome - lethal on neonatal period. None of the newborns had anterior hypophysis and the hypothalamic tumor was apparent in the inferior part of the brain, going from the optic chiasm to the interpeduncular fossa. Besides, other anomalies were found, such as: laryngeal split, abnormal pulmonary lobation, renal agenesis or dysplasia, shorts fourth metacarpals, nail dysplasia, multiple mouth frenulum, hypoadrenalism, congenital cardiomyopathy and intrauterine growth retardation. Every case was sporadic, the chromosome were apparently normal, without consaguinity relations. Several similar, milder and even asymptomatic cases were described later on. Kletter and Biesecker (1992), Topf et all (1993) and Penman Splitt et all (1994), define the disease as dominant autosomal inheritance. Kettler and Biesecker (1992) stated that most cases as sporadic as a result of a gene mutation with variable expressiveness. According to Biesecker et al (1996), an international workshop determined diagnostic criteria to the Syndrome: Hypothalamic Hamartroma and Central Polydactyly; First degree relative with hypothalamic hamartroma and polydactyly; Dominant autosomal parrent inheritance or in a consistent form with germaine mosaicism. The radiological changes are important for differential diagnosis between Pallister-Hall Syndrome and other hamartroma-present diseases. The hypothalamic hamartroma isolated has phenotypical features and causes hormonal disorders such as early puberty. On the MRI (Magnetic resonance imaging) it shows hyperintese sign on attenuated fluid. On the other hand, the Pallister-Hall Syndrome the hamartroma shows itself as a isointense signs along with other deformities as polydactyly, for example. According to Kuo et al (1999), on MRI, the classic hypothalamic hamartroma isn’t calcified, is homogenous and isointense to the grey matter on weight images in T1, and isointense and often hyperintense on weight images in T2. Those findings are pretty distinctive and help distinguish the hypothalamic hamartroma from ordinary lesions, as craniopharyngioma and hypothalamic/opticalchiasmic glioma, observed in children. Case report: The patient ALDV, male, born in 30/12/1995, was referred to evaluation on the Medical Genetic Service from HCPA. At the time, aged one year and 8 months, he was the only son of a young, healthy couple with no consanguinity. The family history of similar cases or other genetic pathologies are unknown. The prenatal happened with no intercurrences, unless the smoking mother. It was a natural birth; Birth Weight: 2kg; High: 42cm; PC: 32cm. APGAR 9. At 8 months, starts an investigation for precocious puberty, and a karyotype was performed in her hometown: 46, XY (normal). He presents convulsive crises since one year old. DNPM: cephalic support when he had 8 months, sat without support at the age of one. Physical examination: Head circumference in the 97th percentile, length above the 97th percentile. Good general condition, dysmorphic, facies with fusion of eyebrows (sinofre), epicanthus, small nose, dysplastic ears with a broad shield, three café-au-lait spots on the body. Presence of pubic hair. Increase in length and diameter of the penis, as well as of the testicles, in relation to chronological age. In the hands, significant brachydactyly with bitateral hexadactyly. In the feet, bilateral hexadactyly. Proximal cutaneous syndactyly between the 2nd and 3rd bilateral arthroids, mainly on the right. Additional exams: Rx of hands and wrists for bone age: 7 years; Chronological Age: 1 year and 10 months. Normal abdominal ultrasound; Computed Tomography of Skull/Magnetic Resonance of Skull: hypothalamic expansive lesion (3 cm), compatible with hamartoma; triventricular hydrocephalus; Cavum septum pellucidum. Endocrinological Evaluation: compatible with precocious puberty of central cause. High resolution karyotype: 46, XY (normal). Computed tomography of the brain: Examination for neurological control, performed on 10/12/2014, 18-year-old patient. It was observed solid nodular formation in the hypothalamic region, hypodense, with well-defined limits, in close contact with the mesencephalon, without impregnation by contrast medium administered intravenously, measuring about 2.9 X 2.4 X 3.0 cm, in the respective laterolateral, anteroposterior and craniocaudal planes, which in correlation with the patient’s clinical history may be related to hypothalamic Hamartoma.
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Shabanov, P. D., S. V. Azarenko, V. V. Lukashkova et A. A. Lebedev. « Effects of peptides orexin and ghrelin on self-stimulation of the lateral hypothalamus in rats after corticoliberin receptors blockade ». Dans II Международная конференция, посвящеенная 100- летию И.А. Држевецкой. СКФУ, 2022. http://dx.doi.org/10.38006/9612-62-6.2022.336.340.
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Li, Guoshi, Stacy Cheng, Frank Ko, Scott L. Raunch, Gregory Quirk et Satish S. Nair. « Computational Modeling of Lateral Amygdala Neurons During Acquisition and Extinction of Conditioned Fear, Using Hebbian Learning ». Dans ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15078.
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The amygdaloid complex located within the medial temporal lobe plays an important role in the acquisition and expression of learned fear associations (Quirk et al. 2003) and contains three main components: the lateral nucleus (LA), the basal nucleus (BLA), and the central nucleus (CE) (Faber and Sah, 2002). The lateral nucleus of the amygdala (LA) is widely accepted to be a key site of plastic synaptic events that contributes to fear learning (Pare, Quirk, LeDoux, 2004). There are two main types of neurons within the LA and the BLA: principal pyramidal-like cells which form projection neurons and are glutamatergic and local circuit GABAergic interneurons (Faber and Sah, 2002). In auditory fear conditioning, convergence of tone [conditioned stimulus (CS)] and foot-shock [unconditioned stimulus (US)] inputs potentiates the synaptic transmission containing CS information from the thalamus and cortex to LA, which leads to larger responses in LA in the presentation of subsequent tones only. The increasing LA responses disinhibit the CE neurons via the intercalated (ITC) cells, eliciting fear responses via excessive projections to brain stem and hypothalamic sites (Pare, Quirk, LeDoux, 2004). As a result, rats learn to freeze to a tone that predicts a foot-shock. Once acquired, conditioned fear associations are not always expressed and repeated presentation of the tone CS in the absence of US causes conditioned fear responses to rapidly diminish, a phenomenon termed fear extinction (Quirk et al. 2003). Extinction does not erase the CS-US association, instead it forms a new memory that inhibits conditioned response (Quirk et al. 2003)
Rapports d'organisations sur le sujet "Lateral hypothalamu"
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Meiri, Noam, Michael D. Denbow et Cynthia J. Denbow. Epigenetic Adaptation : The Regulatory Mechanisms of Hypothalamic Plasticity that Determine Stress-Response Set Point. United States Department of Agriculture, novembre 2013. http://dx.doi.org/10.32747/2013.7593396.bard.
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Our hypothesis was that postnatal stress exposure or sensory input alters brain activity, which induces acetylation and/or methylation on lysine residues of histone 3 and alters methylation levels in the promoter regions of stress-related genes, ultimately resulting in long-lasting changes in the stress-response set point. Therefore, the objectives of the proposal were: 1. To identify the levels of total histone 3 acetylation and different levels of methylation on lysine 9 and/or 14 during both heat and feed stress and challenge. 2. To evaluate the methylation and acetylation levels of histone 3 lysine 9 and/or 14 at the Bdnfpromoter during both heat and feed stress and challenge. 3. To evaluate the levels of the relevant methyltransferases and transmethylases during infliction of stress. 4. To identify the specific localization of the cells which respond to both specific histone modification and the enzyme involved by applying each of the stressors in the hypothalamus. 5. To evaluate the physiological effects of antisense knockdown of Ezh2 on the stress responses. 6. To measure the level of CpG methylation in the promoter region of BDNF in thermal treatments and free-fed, 12-hour fasted, and re-fed chicks during post-natal day 3, which is the critical period for feed-control establishment, and 10 days later to evaluate longterm effects. 7. The phenotypic effect of antisense “knock down” of the transmethylaseDNMT 3a. Background: The growing demand for improvements in poultry production requires an understanding of the mechanisms governing stress responses. Two of the major stressors affecting animal welfare and hence, the poultry industry in both the U.S. and Israel, are feed intake and thermal responses. Recently, it has been shown that the regulation of energy intake and expenditure, including feed intake and thermal regulation, resides in the hypothalamus and develops during a critical post-hatch period. However, little is known about the regulatory steps involved. The hypothesis to be tested in this proposal is that epigenetic changes in the hypothalamus during post-hatch early development determine the stress-response set point for both feed and thermal stressors. The ambitious goals that were set for this proposal were met. It was established that both stressors i.e. feed and thermal stress, can be manipulated during the critical period of development at day 3 to induce resilience to stress later in life. Specifically it was established that unfavorable nutritional conditions during early developmental periods or heat exposure influences subsequent adaptability to those same stressful conditions. Furthermore it was demonstrated that epigenetic marks on the promoter of genes involved in stress memory are altered both during stress, and as a result, later in life. Specifically it was demonstrated that fasting and heat had an effect on methylation and acetylation of histone 3 at various lysine residues in the hypothalamus during exposure to stress on day 3 and during stress challenge on day 10. Furthermore, the enzymes that perform these modifications are altered both during stress conditioning and challenge. Finally, these modifications are both necessary and sufficient, since antisense "knockdown" of these enzymes affects histone modifications, and as a consequence stress resilience. DNA methylation was also demonstrated at the promoters of genes involved in heat stress regulation and long-term resilience. It should be noted that the only goal that we did not meet because of technical reasons was No. 7. In conclusion: The outcome of this research may provide information for the improvement of stress responses in high yield poultry breeds using epigenetic adaptation approaches during critical periods in the course of early development in order to improve animal welfare even under suboptimum environmental conditions.