(n.) The middle segment of the brain; the midbrain. Sometimes abbreviated to mesen. See Brain.
Example Sentences:
(1) 5-HT containing terminals and fibers also were observed in the mesencephalon and appeared to run rostrally in the medial part of the medial forebrain bundle.
(2) Effects of noxious electrical tooth stimulations and intraarterial administration of bradykinin or inhalation of volatile anesthetics on substance P content in the diencephalon-mesencephalon, pons-medulla and the spinal cord were examined in the rat.
(3) In order to study the interactions between serotonergic mechanism and electrical stimulation of the mesencephalic central gray substance, rats were trained to lever-press for terminating aversive electric stimuli applied at the Periaqueductal gray and adjoining tectum of the mesencephalon.
(4) The activity of glycerophosphorylcholine phosphodiesterases was determined in the mesencephalon, diencephalon, cerebral hemispheres, cerebellum and olfactory bulb during postnatal development from P5 to P70 of rat brain.
(5) In addition, these amines caused a concurrent change in the release of ACh at perfusion loci in both thalamus and mesencephalon.
(6) Levels of acetylcholine were significantly elevated in the telencephalon and diencephalon + mesencephalon of rats killed by near-freezing during conditioned suppression of food-reinforced lever pressing, whereas levels of serotonin, dopamine, and norepinephrine were not altered.
(7) The onset of convulsions induced by these convulsants coincides with the fall in GABA content and GAD activity in the mesencephalon area, and in contrast, the cessation of the convulsions by PN supplement coincides with the recovery in both the parameters.
(8) However, a later component of the Cnf-AEP whose generation locus within the mesencephalon is unknown was modulated by bf stimulation.
(9) Six hours after treatment with AOAA the GABA levels in the cerebellum, the cortex, the ventral mesencephalon and the striatum.
(10) Responses of substantia nigra zona compacta neurons to nomifensine and amantadine were studied with intracellular recording techniques (current and voltage clamp) in in vitro slice preparation of rat mesencephalon.
(11) These results describe a novel neurochemical system within the rat basal ganglia that is regulated by dopaminergic innervation from the mesencephalon.
(12) The left vertebral angiography revealed an anteriovenous malformation in the mesencephalon mainly feeded by the thalamoperforate artery and the medial branch of the posterior choroidal artery.
(13) (1) In 27 animals microinjection of 25--100 ng of angiotensin II through chronic cannulae implanted in the preoptic region initiated drinking and in subsequent acute experiments influenced the spontaneous discharge rate of single neurons in the ipsi-lateral mesencephalon.
(14) Into the second week of embryo growth (E7-E15), GABA appears in the mesencephalon (E7) and the eye (E9-E10).
(15) Behavioral augmentation also has been shown with opioids such as morphine, and it is known that a stimulant action on dopaminergic perikarya in the ventromedial mesencephalon is critical to the development of behavioral sensitization to morphine.
(16) Since EKC- and NANM-induced cardiovascular and respiratory depression were not observed in conscious intact or chronic spinal dog, it is suggested that: 1) kappaergic system rostral to mesencephalon may play a role in counteracting these depressant effects of EKC; 2) sigma receptor-mediated tachypnea and tachycardia are dissociable; the tachypneic effect may be mediated through higher center while the medulla oblongata is involved in producing tachycardia.
(17) Critical points of changing axial orientation were identified at the mesencephalon, the Rathke pouch and third branchial arch, and with the hepato-cardio-respiratory complex split between the 2 axes.
(18) The local cerebral blood flow and oxygen tension in the brain cortex, the reticular formation of the mesencephalon and the posterior hypothalamus were studied in chronic experiments in non-anesthetized rabbits with experimentally induced myocardial infarction.
(19) The variation was in the order leptomeninges greater than hypothalamus greater than cerebral cortex = mesencephalon greater than cerebellum = brain stem.
(20) In the present work, using the indirect peroxidase-labelled antibody technique, we made a comparative study about the distribution of Met-enkephalin-like-immunoreactive (ELI)-cell bodies in rat mesencephalon; comparing animals that received colchicine into the lateral ventricle and animals that got the colchicine injected into different cerebral nuclei.
Thalamus
Definition:
(n.) A mass of nervous matter on either side of the third ventricle of the brain; -- called also optic thalamus.
(n.) Same as Thallus.
(n.) The receptacle of a flower; a torus.
Example Sentences:
(1) While the heaviest anterogradely labeled ascending projections were observed to the contralateral ventral posterolateral nucleus of the thalamus, pars oralis (VPLo), efferent projections were also observed to the contralateral ventrolateral thalamic nucleus (VLc) and central lateral (CL) nucleus of the thalamic intralaminar complex, magnocellular (and to a lesser extent parvicellular) red nucleus, nucleus of Darkschewitsch, zona incerta, nucleus of the posterior commissure, lateral intermediate layer and deep layer of the superior colliculus, dorsolateral periaqueductal gray, contralateral nucleus reticularis tegmenti pontis and basilar pontine nuclei (especially dorsal and peduncular), and dorsal (DAO) and medial (MAO) accessory olivary nuclei, ipsilateral lateral (external) cuneate nucleus (LCN) and lateral reticular nucleus (LRN), and to a lesser extent the caudal medial vestibular nucleus (MVN) and caudal nucleus prepositus hypoglossi (NPH), and dorsal medullary raphe.
(2) The hippocampus plays an essential role in the laying down of cognitive memories, the pathway to the frontal lobe being via the MD thalamus.
(3) Neurons containing moderate to high concentrations of ChE reaction product were found in 3 distinct regions of the dorsal thalamus.
(4) Morphological results demonstrated that 30 Gy irradiated animals showed extensive necrosis primarily in the fimbria, which extended into the internal capsule, optic nerve, hippocampus, and thalamus.
(5) The occurrence of paresis or paralysis in ischemic processes strictly situated in the thalamus, however, is discussed: the deficit may be limited to parts of limbs; most often, it is not associated with pyramidal symptomatology; recovery is observed in the hand before the inferior limb.
(6) The presence of gelatinosa neurons projecting to the thalamus emphasizes a point made in earlier reports, that these neurons do not form an homogeneous population.
(7) The existence is therefore proposed of some neural mechanism that controls the higher cerebral function of writing via the thalamus.
(8) To identify the origin of scalp-recorded far-field negativity of short-latency somatosensory evoked potentials to median nerve stimulation (designated N18), direct records were made from the thalamus and ventricular system during 4 stereotaxic and 3 posterior fossa operations.
(9) The neighbouring neocortical areas receive afferents neither from the mediodorsal nucleus of the thalamus nor from the ventral mesencephalic tegmentum; their catecholamine innervation is mainly confined to the superficial layers and appears to be of noradrenergic nature.
(10) The tonic influences were expressed in an increase in the amplitude parameters of the responses of the visual cortex in conditions of the formation in the posterolateral nucleus of the thalamus of a focus of heightened excitability (anode polarization), and their perceptible diminution with potassium depression in this nucleus.
(11) Glutamate-immunoreactive neurons were present throughout the acoustic thalamus, including the regions containing the retrogradely labeled neurons.
(12) Neutral aminopeptidase activity showed a significant decrease in the thalamus and cerebellum with marked (not significant) changes in the hypothalamus, hippocampus, medulla, and occipital cortex.
(13) CT findings of 6 cases with germinoma originating in the basal ganglia and thalamus are reported.
(14) Parkinsonism in the present case may be due to the involvement of multiple neuronal circuits of the extrapyramidal system at the level of the midbrain to the thalamus.
(15) Thus, the possibility of defects at other sites, such as the globus pallidus or thalamus must be considered.
(16) Histochemically the lowered activity of enzymes was localized mainly in the neuropil of: striatum, the Broc's nuclei and rhinencephalon: in the nervous cells of: Ammon's horn, nuclei of thalamus and in neocortex.
(17) Peripheral nerve grafts were inserted into the thalamus in 27 Sprague-Dawley rats.
(18) For the stereotactic treatment of Parkinson's disease, the target is usually located in the thalamus; this point is related to nearby structures (third ventricle).
(19) CT findings of them revealed that the hematomas were large or invaded toward the internal capsule and thalamus.
(20) Background activity recorded extracellularly from three anterior (limbic) nuclei of the thalamus was analyzed in chronic unanesthetized rabbits.