(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.
Pons
Definition:
(n.) A bridge; -- applied to several parts which connect others, but especially to the pons Varolii, a prominent band of nervous tissue situated on the ventral side of the medulla oblongata and connected at each side with the hemispheres of the cerebellum; the mesocephalon. See Brain.
Example Sentences:
(1) The pons, on the other hand, has a bioelectrical activity of its own during PS, i.e., the ponto-geniculo-occipital spikes (PGO).
(2) These included the noradrenergic, TH- and DBH-immunoreactive cell groups of the pons and medulla.
(3) + inf., pons + medulla), rCBF increased toward the control level gradually, and it completely recovered 60 min after recirculation.
(4) Injection of the tracer substance wheat germ agglutinin-horseradish peroxidase (WGA-HRP) directly into the basilar pontine nuclei using a ventral surgical approach resulted in the labeling of somata in many areas both rostral and caudal to the basilar pons.
(5) Urea decreased and valine increased in the TD medulla-pons.
(6) Recently, direct pathways from the dorsolateral pons to the ON, probably involved in supraspinal micturition control, have been reported (Holstege et al., 1986).
(7) In the pons, PRV labeled neurons were found bilaterally in the locus ceruleus, subceruleus region, and parabrachial complex.
(8) P3.1 and P3.8 were identified only as farfield potentials in intracranial recordings from the pons and more rostral regions.
(9) Computed tomography showed a lesion in the pons, and seven months later he was found to have metastatic adenocarcinoma.
(10) Weaker linkage between the CF locus and the locus for the serum enzyme activity marker paraoxonase (PON) was detected, theta = 0.18, zeta = 0.76.
(11) In the medulla and pons the ir appeared as from E12.
(12) Pons-Tortella et al reported the sparing of this nucleus in acute anterior poliomyelitis.
(13) 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.
(14) Synchronization of phasic bursts was consistently observed between simultaneously recorded structures and this, along with the time course of early increments in SW was consistent with the notion that mesencephalic reticular activity is controlled by leading influences from the pons.
(15) Specifically, a decrease in the central conduction times was noted for the I-III interpeak interval, suggesting neurophysiologic dysfunction in the area of the pons and cerebellum.
(16) Among them, two patients had deformities of the pons.
(17) This study examines the effects of styrene oxide, a reactive metabolite of the neurotoxic solvent styrene, on GSH metabolism in six regions of the rat brain (cortex, cerebellum, medulla-pons, hippocampus, striatum and hypothalamus).
(18) The course of the fiber pathways to pons from parasensory association areas in the rhesus monkey was investigated by injection of tritiated amino acids and the technique of autoradiography.
(19) 1 The ability of chlorpromazine to antagonize the effects of iontophoretic application of (+)-amphetamine to single neurones in the medulla and lower pons of anaesthetized rats has been studied.
(20) Noradrenaline concentration was elevated in the brain stem, particularly in the pons, and decreased in the cerebral cortex and the spinal cord while in the cerebellum, the effects were dependent on the mode of administration.