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Twenty-one patients affected by extrapyramidal disorders were polygraphically recorded during spontaneous nocturnal sleep for two consecutive nights to assess their sleep and movement patterns. The patients (pts) sample included: Gilles de La Tourette syndrome (TS, nine pts), neuroacanthocytosis (NA, six pts) and Hungtington's chorea (HC, six pts). Sleep(More)
Intra-axonal recordings were obtained from single afferent fibres of the posterior nerve in the isolated labyrinth of the frog (Rana esculenta). EPSPs and spike discharge were recorded both at rest and during rotatory stimulation of the canal. Electrical stimulation of either the distal end of the cut posterior nerve or of the central stumps of the(More)
Glass microelectrode recordings were made from single fibres of the posterior ampullary nerve in the isolated labyrinth of the frog (Rana esculenta). Potentials were recorded both at rest and during rotatory stimulation of the canal. At rest, the tracings revealed an intense background of small, largely summated potentials (0.5-10 mV amplitude, 3-6 msec(More)
The slow potentials and afferent discharge of impulses in frog semicircular canals have been studied at different endolymphatic and perilymphatic K+ concentrations. Results indicate that the presence of K ions in the bathing fluids is essential for maintaining the receptor function in crista ampullaris, although very low concentrations of this ion in the(More)
Ionic mechanisms sustaining sensory transduction in crista ampullaris sensory cells have been investigated chiefly by replacing the endolymph with solutions with K+ and Ca++ chelators added. The effects of the modified solutions were evaluated by extracellular and intracellular recordings of both and the presynaptic and postsynaptic activity of ampullar(More)
L-glutamate (Glu) has at least two sites of action in the frog semicircular canal: the hair cell (presynaptic) and the primary afferent nerve fibres (postsynaptic). Glu's action on the hair cell results in an increased release of the natural transmitter which is responsible for a substantial increase in the frequency of firing in primary afferents. The(More)
The distribution and the properties of efferent fibers in vestibular nerve were studied in the isolated frog labyrinth. Electrical stimulation of the central stump of any vestibular nerve branchlet elicited compound action potentials in all the other eighth nerve branchlets, indicating the existence of neural links between the various vestibular organs. The(More)
The role of various ions in stimuli conversion has been investigated in isolated frog semicircular canals, by replacing the endolymph with solutions deprived in turn of Na+, K+, Cl- and Ca++. Mechanical and electrical stimuli were employed and slow ampullar and nerve potentials were recorded, together with the afferent discharge of impulses in the eighth(More)
The functional organization of the efferent vestibular system (EVS) was studied in the isolated frog labyrinth. To ascertain whether, besides the efferent branching fibres that innervate several end-organs, the EVS is also endowed with efferent non-branching axons which might control a given population of sensory units in each end-organ, the 8th nerve and(More)
Structural alterations of subcutaneous small resistance arteries, as indicated by an increased media:lumen ratio, are frequently present in hypertensive and/or diabetic patients and may represent the earliest alteration observed. In addition, media:lumen ratios of small arteries have a strong prognostic significance. However, no data are available about the(More)