Search results for "medulla oblongata"

Separate and Combined Effects of a Benzodiazepine (Alprazolam) and Noise on Auditory Brainstem Responses in Man

1999

Auditory brainstem responses (ABRs) were recorded in 60 male or female, anxious or anxiety-free university students, before and after separated or simultaneous intake of alprazolam and exposure to noise. A significant increase of the latencies of the ABRs was found when subjects took alprazolam. This effect is consistent with the presence of gamma-aminobutyric acid (GABA), one of the neurotransmitters at terminals of cochlear efferent fibres A significant increase of the latencies was observed after noise alone. In subjects taking alprazolam when they are exposed to noise, the effect of noise on the ABR latencies is reduced, but not abolished. The effects of alprazolam on the ABR are consis…

Medullary respiratory-related neurons with axonal connections to rostral pons and their function in termination of inspiration.

1985

In urethane-anaesthetized, paralyzed and artificially ventilated rabbits, medullary respiration-related neurons (RRU) were classified according to the phase relation of their burst discharge to phrenic nerve activity. Phase-bound inspiratory (I) or expiratory (E) neurons were discriminated from phase-spanning expiratory-inspiratory (EI) or inspiratory-expiratory (IE) units. Mechanisms of termination of inspiration by electrical stimulation of rostral pontine nuclei (Nc. parabrachialis medialis; Lc. coeruleus) were examined firstly to demonstrate whether RRU receive descending excitatory and inhibitory afferents as well as ascending efferents and secondly to analyse the time course of the ne…

Landmarks for vertebral artery repositioning in bulbar compression syndrome: anatomic and microsurgical nuances

2004

Abstract OBJECTIVE: The purpose of this study was to better elucidate the anatomic relationship between the vertebral artery (VA) along with its perforating vessels and the brainstem to develop anatomic guidelines that would be helpful when decompressing medulla oblongata compressed by the VA. METHODS: Microanatomy dissection was performed in six formalin-fixed cadaveric heads. The VA, posteroinferior cerebellar artery (PICA), anteroinferior cerebellar artery (AICA), and lower brainstem perforators were examined under magnification using a surgical microscope. The outer diameters of the VA, PICA, and AICA were measured. The distance between the VA, lying within the lateral cerebellomedullar…

Temporal retrogasserian resection of trigeminal root versus controlled elective percutaneous electrocoagulation of the ganglion of gasser in the trea…

1972

In his experience with 531 surgical procedures for the relief of trigeminal neuralgia between 1955 to 1970, the author developed a strong preference for the percutaneous electro-coagulation of the gasserian ganglion. Although the method was repeatedly modified in the early years, a standardized technique of controlled, selective and fractional coagulation in the semiawake state of neurolept-anaesthesia was used since 1963 in 183 of his 311 patients, treated in this manner. The advantages of the method, particularly in comparison to open intracranial root sections, are: Minimal operative risk, control of operative effect during the operation, small sensibility deficit, low rate of complicati…

Influence of rubrospinal tract and the adjacent mesencephalic reticular formation on the activity of medullary respiratory neurons and the phrenic ne…

1988

Suprapontine brain sites acting on the central respiratory system have been demonstrated to give rise to inspiratory as well as expiratory facilitatory effects. In the present study the inspiratory inhibitory effect which has been reported in the cat to be elicited consistently by electrical stimulation of the rubrospinal tract and the adjacent mesencephalic reticular formation was examined in the urethane-anaesthetized rabbit. Stimulation of these sites with single electrical shocks of moderate intensity induced a short latency (onset after 3.0 ms) transient (duration: 29 ms) inhibition of the phrenic nerve activity (PHR). Short volleys of stimuli applied in mid- to late-inspiration led to…

Topodiagnostic implications of hemiataxia: An MRI-based brainstem mapping analysis

2007

The topodiagnostic implications of hemiataxia following lesions of the human brainstem are only incompletely understood. We performed a voxel-based statistical analysis of lesions documented on standardised MRI in 49 prospectively recruited patients with acute hemiataxia due to isolated unilateral brainstem infarction. For statistical analysis individual MRI lesions were normalised and imported in a three-dimensional voxel-based anatomical model of the human brainstem. Statistical analysis revealed hemiataxia to be associated with lesions of three distinct brainstem areas. The strongest correlation referred to ipsilateral rostral and dorsolateral medullary infarcts affecting the inferior ce…

Complications in Craniovertebral Junction Instrumentation: Hardware Removal Can Be Associated with Long-Lasting Stability. Personal Experience

2017

Background The causes of craniovertebral junction (CVJ) instabilities include trauma, rheumatological diseases, tumors, infections, congenital malformations, and degenerative disease processes; these complex pathologies often require CVJ instrumentation. Hardware complications were analyzed in a personal series of 48 treated patients. In light of the analysis of very unusual radiological and clinical findings, the authors tried to better investigate the related mechanisms and to reach possible useful conclusions. Methods In a series of 48 patients who underwent CVJ instrumentation and fusion procedures in our Institution, we describe three cases of hardware failure, due to: (1) infection; (…

Metabolic control of respiratory neuronal activity and the accompanying changes in breathing movements of the rabbit

1976

Expiratory-related neurons have been classified according to their phase relation within the respiratory cycle, their response to lung distension and collapse (α- and β-type), and to hyperventilation (tonic firing denoted by “+”, cessation of activity by “−”). The dorsal surface of the medulla oblongata was superfused with a metabolite-containing CSF solution and the activity of expiratory (E) and inspiratory-expiratory (IE) neurons was extracellularly recorded. The neuronal sub-types established by their functional behaviour could equally be distinguished by their differential response to one or several metabolites. In contrast to inspiratory (I) neurons, E − α , E + β , E − β and IE − β n…

NEUROPHYSIOLOGICAL AND NEUROCHEMICAL STUDIES WITH THE ISONICOTINOYLHYDRAZONE OF PYRIDOXAL 5-PHOSPHATE.

1964

AN ULTRASTRUCTURAL STUDY OF THE RETINA IN HUMAN LATE INFANTILE NEUROAXONAL DYSTROPHY

1993

A case involving a girl who died at 11 years of age and who had developed normally until the age of 18 months, at which time further psychomotor maturation stopped and then regressed, is reported. The patient appeared hypotonic and showed loss of deep tendon reflexes, as well as bulbar signs and increasing immobility. Visual impairment resulted in blindness at the age of 7 years. Her disease was diagnosed as late infantile neuroaxonal dystrophy (LINAD) after examination of sural nerve biopsy samples and after autopsy. Under electron microscopy, retinal axons were filled with tubulocisternal profiles and occasional large lamellar clefts close to or distant from synaptic complexes. These lesi…