RESUMEN

We obtained the venograms using the two-dimensional digital subtraction angiography (2D DSA) images and three dimensional rotation venography (3D RV) images and investigated the potential usefulness of the 3D RV compared with venograms of 2D DSA using the newly developed three-dimensional rotation angiography unit with a flat-panel detector (FPD). This study included 26 sides (11 left, 15 right) in 20 cases (4 males and 16 females) who underwent radiographic examination for management of intracranial tumors and vascular diseases between May 2003 and December 2003. Each patient underwent diagnostic angiography performed on a DSA unit with a FPD. In all patients, the 2D DSA images, including anteroposterior view and lateral view of the carotid artery, were obtained in two stereoscopic views. The 3D RV was used to produce volume-rendered images. Two neuroradiologists investigated the venous configuration of 3D RV compared with that of 2D DSA about the relationship of the venous drainage system on the temporal lobe according to Guppy et al.'s classification. Twenty-four sides of the 26 sides enabled the precious visualization on 3D RV images. In investigation of 2D DSA, 9 sides (37.5%) were classified into type A, 13 (54.2%) into type B, two (8.3%) into type C, and no sides into types D, E, and F. In investigation of 3D RV images, 10 sides (41.7%) were classified into type A, 9 (37.5%) into type B, 1 (4.2%) into type C, 2 (8.3%) into type E, and 2 (8.3%) into type F. Seven of 24 sides demonstrated discrepancy in results between 2D DSA and 3D RV. The 3D RV could be performed by setting the adequate delay in between the injection of the contrast material and starting time of third rotation to acquire the opacified images. In Guppy et al.'s classification, the 3D RV images could demonstrate the precious venous drainage including the venous lakes with use of multiple views and variable reconstruction compared with 2D DSA. Our DSA system with FPD could provide good 3D RV images. These images are very useful for the skull-base surgery because we can understand the three-dimensional vascular anatomy preoperatively.

Asunto(s)

RESUMEN

The present study was undertaken to investigate firing patterns, locations, and projections to the phrenic motor nucleus of respiratory neurons in medullary raphe nuclei of rat. Experiments were performed on spontaneously breathing rats anesthetized with sodium pentobarbital. Extracellular spikes of single respiratory neurons were explored in midline medullary tegmentum. A total of 107 respiratory neurons was recorded in the raphe magnus, obscurus and pallidus. They were classified into the following eight types based on the relation of their firing patterns to the phase of respiration: (1) Inspiratory (I) throughout (n = 42); (2) I-late (n = 9); (3) I-decrementing (n = 1); (4) Pre-I (n = 2); (5) I-frequency modulated (n = 13); (6) Post-I (n = 12); (7) Expiratory (E) (n = 23) and (8) E-frequency modulated neurons (n = 5). Twenty of the 45 respiratory neurons examined were antidromically activated from the phrenic motor nucleus at the C4 spinal level with thresholds of 2-58 microA and latencies of 0.4-2.4 ms. Among the 20 neurons, 11 neurons were I-throughout, five were I-frequency modulated and four were E neurons. These results suggest that there is a population of neurons in the medullary raphe nuclei that projects to the phrenic motor nucleus at the C4 spinal level. It is possible that this projection may, in part, mediate the control of the diaphragmatic muscle motor neurons located in the C4 segments.

Asunto(s)

RESUMEN

This study was undertaken to investigate vestibulothalamocortical pathways in anesthetized cats. Synaptic connections of posterior canal-activated excitatory vestibuloocular relay (PC) neurons to thalamic neurons were examined by a spike-triggered averaging technique. The averaged potentials evoked in the ventrobasal complex of the thalamus revealed a negative wave with latencies from 0.8 to 1.5 ms. Thirty-six thalamic neurons, which were activated by nose-up head rotation and by contralateral labyrinth stimulation, were mainly located in the ventrobasal complex. Thirteen of these neurons were antidromically activated from the anterior suprasylvian sulcus or postcruciate dimple of the cortex. These results suggest that the PC neurons participate, at least in part, in the vestibulocortical pathways contributing to spatial orientation.

Asunto(s)

RESUMEN

We have previously reported that axon collaterals of posterior canal-activated excitatory vestibular (PC) neurons project to the contralateral oculomotor nucleus, and rostrally to the thalamus. To elucidate the vestibulothalamocortical pathways we investigated the synaptic connections of the PC neurons with the thalamic neurons by post-spike averaging of compound potentials triggered by spikes of the PC neuron in anesthetized cats. The averaged field potential evoked in the ventrobasal complex (VBC) revealed a spike followed by a negative wave. Latencies of the wave ranged from 0.8 to 1.5 ms. Next, we examined the location and axonal projection of 36 thalamic neurons which were activated by nose-up head rotation and by contralateral labyrinth stimulation. Most of them were located in the VBC and some in the medial geniculate body. Thirteen of the 36 neurons were antidromically activated from the anterior suprasylvian sulcus or postcruciate dimple of the cortex. These results suggest that the PC neurons participate, at least in part, in the vestibulocortical pathways contributing to spatial orientation.

Asunto(s)

RESUMEN

The axonal projections of 62 posterior canal (PC)-activated excitatory and inhibitory secondary vestibular neurons were studied electrophysiologically in cats. PC-related neurons were identified by monosynaptic activation elicited by electrical stimulation of the vestibular nerve and activation following nose-up rotation of the animal's head. Single excitatory and inhibitory neurons were identified by antidromic activation following electrical stimulation of the contralateral and ipsilateral medial longitudinal fasciculus, respectively. The oculomotor projections of identified neurons were confirmed with a spike-triggered averaging technique. The axonal projections of the identified neurons were then studied by systematic, antidromic stimulation of the mesodiencephalon. Excitatory neurons showed two main types of axonal projections. In one type, axonal branches were issued to the interstitial nucleus of Cajal, central gray, and thalamus including the ventral posterolateral, ventral posteromedial, ventral lateral, ventral medial, centromedian, central lateral, lateral posterior, and ventral lateral geniculate nuclei. The other type was more frequently observed, giving off axon collaterals to the above-mentioned regions and to Forel's field H as well. Inhibitory neurons issued axonal branches to limited areas which included the central gray, interstitial nucleus of Cajal, its adjacent reticular formation and caudalmost part of Forel's field H, but not the rostral part of the Forel's field H and the thalamus. These results suggest that PC-related excitatory neurons participate in the genesis of vertical eye movements and in the perception of the vestibular sensation, and that PC-related inhibitory neurons seem to take part only in the genesis of vertical eye movements.

Asunto(s)

RESUMEN

Extracellular spikes of single respiratory neurons were explored in the medullary raphe nuclei in spontaneously breathing decerebrated or Nembutal-anesthetized cats. A total of 26 respiratory neurons, whose spikes were confirmed to originate from the cell bodies, was recorded in the raphe obscurus and pallidus. They could be classified into six types based on the relation of their firing to the phases of respiration: (1) inspiratory (I) decrementing (I-DEC, n = 14), (2) I-frequency modulated (n = 3), (3) I-augmenting (I-AUG, n = 2), (4) late I (n = 2), (5) expiratory (E) augmenting (E-AUG, n = 3) and (6) I-E phase-spanning (I-E PS, n = 2). These results suggest the existence of neurons relating to the control of respiration in the medullary raphe nuclei.

Asunto(s)

RESUMEN

We developed a new digital subtraction angiography (DSA) technique for venography of the legs. Satisfactory venograms were obtained by recording the venous images on videotape with on-line fluoroscopic monitoring followed by enhancement of the images by an image processor.

Asunto(s)

Asunto(s)

RESUMEN

Polysomnographic recordings were done over continuous 3 days together with those of electrical and mechanical activities of the stomach using chronically implanted electrodes and force-transducer in unanesthetized and unrestrained state of 4 adult cats. Circadian rhythm of the basic electric rhythm (BER) and mechanical activity in the stomach accustomed to feeding schedule of once a day was divided into the two; the fed state from the end of feeding to 8 to 11 hr later and the succeeding fasting state. However, differentiation of the fasting state into the contractile and noncontractile periods, which is known in dogs, was not evident in cats. The mean BER interval was longer and the standard deviation was smaller in the fed state than in the fasting state. Among stages of wakefulness (W), drowsiness (D), light slow wave sleep (LS), deep slow wave sleep (DS) and REM sleep, the mean BER intervals in every total time during the fed state were compared with one another. A definite unidirectional finding obtained in all 4 cats was only that the mean BER intervals in the stage D were longer significantly than those in the stage W.

Asunto(s)