(n.) The middle segment of the brain; the mesencephalon. See Brain.
Example Sentences:
(1) However, this inhibition was not found in rats treated with castor oil for 3 d. Moreover, 5-HT concentration in the midbrain significantly decreased in rats that acquired the adaptability for the occurrence of diarrhea.
(2) A train of conditioning stimuli to either of the midbrain nuclei produced inhibition of evoked population spikes recorded in the CA1 pyramidal cell layer of the hippocampus.
(3) Electrophysiological methods were used to determine changes in the neural representation of the binocular visual field at the paired midbrain optic tecta and in the tectal projection of pairs of corresponding retinal loci at various developmental points between these ages.
(4) Intracerebral injection of the GABAA agonists muscimol (1 nmol), isoguvacine (1 nmol) or THIP (1, 2 and 4 nmol) in rats with chemitrodes implanted in the dorsal midbrain central grey raised the threshold electrical current for inducing escape behaviour.
(5) Striking similarities were found between the functional pathways affected differentially by RET stimulation and well-defined cholinergic pathways which originate in the midbrain tegmentum.
(6) These responses were prominent in the rostral midbrain.
(7) Single neurons in the midbrain tegmentum of rats showed clear discriminatory responses to three tones announcing either food or water or no reinforcement.
(8) Stimulation using implanted electrodes in conscious rats, within the hypothalamic and midbrain areas described above, elicited typical 'flight' and 'escape' behaviour: thus, the localized regions from which the visceral alerting response is elicited contain neurones or nerve fibres integrating the whole defence-alerting response in the rat, as in other species.
(9) ruber, anterodorsolateral midbrain tegmentum, superior and inferior colliculi, pontine gray, cerebral peduncles, medial pontine reticular formation, raphe and vestibular nuclei did not affect the acoustic structure of the calls tested.
(10) This paper describes the distribution of histamine-like immunoreactivity in the midbrain and suboesophageal ganglion of the sphinx moth Manduca sexta.
(11) 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.
(12) As a result the dipole of the wave V of auditory brainstem responses was found near the contralateral midbrain.
(13) In the latter tumors, a peculiar ataxic hemiparesis syndrome is produced by midbrain compression.
(14) Fewer, but still ample numbers, of SP-reactive axons are present also in the ventral tegmental and retrorubral areas of the midbrain tegmentum and in the ventral pallidum of the basal forebrain, but only sparse ME-reactive axons are present in these areas.
(15) In the investigation, the neocortex was represented by the frontal cortex (field 10), the old cortex by the hippocamp, the midbrain by black substance, and medulla oblongata by the inferior olive.
(16) The anxiolytic activity of serotonin agonists (buspirone, ipsapirone, campirone, caplapirone, 1-pyrimidinyl-piperazine) determined in rats on 3 experimental models of anxiety closely correlates with the degree of inhibition of impulse release of 3H-serotonin by electrically stimulated slices of the midbrain raphe dorsal nucleus (r = +0.85) but not the slices of the cerebral hemispheric cortex (r = +0.60) of the rats.
(17) The level of 5-HT was diminished in dorsal spinal cord and midbrain, whereas NE appeared unchanged.
(18) Movement-correlated firing was studied in 111 midbrain neurons recorded in freely behaving hamsters.
(19) These results suggest that different fibers with overlapping spatial distributions contribute to analgesia and vocalizations produced by midbrain stimulation.
(20) alpha-Fluoromethylhistidine, a histidine decarboxylase inhibitor, induced a significant depletion in the hypothalamic, midbrain, and cortical brain histamine amounts in 12- and 3-month-old rats.
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.