PubMed Health⌕ Search

Biomedical subjects

F Cicirata

Publications and source records attributed to F Cicirata.

At least 55 records · Page 3Linked to original sources
PubMed1983

[Ponto-medullary projections to the spinal cord: a quantitative study in the cat].

The purpose of this research has been to study quantitatively the ponto-medullary projections to the lateral and ventral funiculi in both cervical (C3) and thoracic (Th8) levels. The method consisted in the partial interruption of the spinal cord, sparing one funiculus in which 5-30 microliter of HRP 30% solution was injected at about 1 cm caudally. 19 cats were utilized, 12 for cervical (6 for lateral and 6 for ventral funiculus) and 7 for lumbar injection (3 for lateral and 4 for ventral funiculus). The structures which project to both funiculi of spinal cord (RM, RL, Poo, PR at Th8 level; RM, RL, Poo at C3 level) could exert integrative effects on the proximal and distal segments of the limbs. The structures which project only to FV (VL and Poc at Th8 level; VL, VIN and Poc at C3 level) or to FL (LSC at Th8; PR at C3) could be implied in motor control of only the proximal or distal regions.

Animals↗
PubMed1982

An autoradiographic study of the cerebellopontine projections in the rat. I. Projections from the medial cerebellar nucleus.

The medial cerebellar nucleus of the rat is shown by the autoradiographic technique to project to both the contralateral nucleus reticularis tegmenti pontis and the pontine nuclei proper. The former projection is more concentrated in the medial--parvocellular --region. In the pontine gray, the bulk of the projection concerns the dorsal aspect of the medial nucleus. Rostral parts of the medial cerebellar nucleus project to caudal pontine levels whereas caudal parts seem to project throughout the rostrocaudal extent of the basilar pons.

Animals↗
PubMed1982

[Electroencephalographic changes during nocturnal sleep in subjects with familial cortico-cerebellar atrophy].

The purpose of this research was to analyze the qualitative and quantitative EEG sleep alterations in four subjects affected by familiar cerebellar atrophy and in their blood relations, who were clinically healthy. Polygraphic sleep registrations (including EEG, EOG, EMG, ECG and except in two cases, EPG), computerized cranial tomography and clinical evaluation were carried out in all subjects. The EEG sleep records of subjects afflicted by cerebellar atrophy showed quantitative alterations, namely reductions of IV phase and REM, with an increase of the intermediary phase between synchronized and desynchronized sleep. The qualitative characteristic were: slow and recurrent changing phases, instable periods of sleep with frequent fragmentations, numerous arousals, intermediary phases corresponding to the II studies of Barros-Ferreira and in only two cases, presence of spindle activity during REM sleep. Two blood relations showed EEG sleep alterations similar to the atrophy subjects. According to the common genotype and similar EEG sleep abnormalities, we suggest that the latter, in these two subjects, may be produced by small cerebellar lesions, which are insufficient for a clear clinical symptomatology.

Adult↗
PubMed1982

Cerebellar nuclear topography of simple and synergistic movements in the alert baboon (Papio papio).

Movements elicited by the stimulation of the cerebellar nuclei were studied in alert baboons chronically prepared. The motor responses were filmed and recorded in eight muscles through chronically implanted electrodes. Two types of motor effects were observed: (1) Simple movements that concerned the unidirectional displacement of a limb segment. (2) Complex movements that involved distinct and frequently noncontiguous muscles were stereotyped and could not be dissociated. These movements are defined as motor synergies. Electromyographic study allowed us to investigate the motor response latencies and the modality of cerebellar control on musculature. Simple movements were due to the activation of muscles within the involved segment in addition to the co-contraction of muscles of a nearby segment. Thus they could be due to a cerebellar control over muscular synergies. Complex movements would correspond to the simultaneous activation of distinct muscular groups and could also be the outcome of a cerebellar control on motor synergies. Thus the effects of the interposed nucleus concern preferably flexor muscles whereas the effects of the dentate nucleus appear to be equally distributed among flexor and extensor muscles. Somatotopic motor localization were evidenced both in the interposed and dentate nuclei: there are somatotopic relations between every region of the interposed nucleus and musculature. As regards the dentate nucleus, two subdivisions were distinguished according to the complexity of elicited motor effects: (A) an antero-medial region from which motor synergies can be elicited. (B) a postero-lateral region giving rise to simple movements, mainly hand movements.

Animals↗
PubMed1982

Cerebello-olivary projections in the rat. An autoradiographic study.

Projections of deep cerebellar nuclei onto the inferior olive have been studied using autoradiographic methods in adult Wistar rats: the distribution of the labelling consequent to injections of tritiated amino acids, limited to one of the cerebellar nuclei, was mapped in the inferior olive. Each of the four cerebellar deep nuclei project to a specific region of the contralateral inferior olive. Only caudal parts of the medial cerebellar nucleus send fibres to the olive, where they reach the caudal half of the medial accessory olive. Anterior and posterior interposed nuclei project to the dorsal accessory and the rostral half to the medial accessory olives, respectively. The lateral, or dentate nucleus projects to the principal olive. This projection discloses a clear-cut topological arrangement. Besides, a few dentato-olivary fibres recross the midline in the interolivary region and end in areas of the ipsilateral principal olive symmetric to the contralateral projection. These results are discussed with special consideration to comparative anatomy.

Animals↗
PubMed1981

Contribution of the dentato-thalamo-cortical system to control of motor synergy.

Stimulation of the dentate nucleus in the chronically implanted baboon elicits both movements restricted to a single joint and also complex movements of several body segments. The complex movements correspond to precise but stereotyped coordinating activity. Two types of data reveal that the cerebello-thalamo-cortical system is concerned in the elaboration of complex movements. (1) Examination of cortical, pyramidal and muscle response latencies shows that the message might be transmitted by this pathway. (2) The complex movement which is produced by stimulation of a site in the dentate nucleus is similar to the sum of movements induced by stimulation of each cortical point receiving excitatory projection from this particular dentate focus.

Animals↗
PubMed1980

[Simple and synergistic motor effects, induced by the stimulation of the dentate nucleus, in the awake baboon. Determination of the area of hand control].

In the Baboon, two regions could be distinguished within the dentate nucleus according to the complexity of motor effects induced through localised electrical stimulation. (a) A rostromedial region, from which synergistic effects were elicited. This part mainly controls proximal muscles. (b) A caudolateral region from which simple movements were induced. A separate area for hand control could be identified within this part of the nucleus.

Animals↗
PubMed1980

[Convergence effects evoked in neurons of the thalamic ventrolateral (VL) nucleus by the stimulation of paleo- and neocerebellar nuclear efferents].

The functional characteristics of the cerebellar nuclear outputs (fastigial, F.; interpositus, I.; dentate, D. nuclei) convergence on single neurones of th ventrolateral (VL) thalamic nucleus were studied in chloralosed, curarized and artificially ventilated cats (pCO2 continuously monitored), by means of the usual electrophysiological stimulation and intracellular recording techniques. From the experimental results on 90 VL n. neurones, with the analysis of the evoked cerebellar nuclear outputs unitary responses, it is possible to conclude: a) 69% of the reactive VL n. units are convergence neurones (CN); b) 34% of the CN are reactive to stimulation of all three cerebellar nuclei, showing similar patterns, with predominantly excitatory effects when located in the dorso-medial VL n. region and opposite patterns (excitation and inhibition) when located in the ventro-lateral VL n. region; c) 30% of the CN are reactive to the F.n and I.n. stimulation, often with opposite patterns; d) 36% of the CN are reactive to the D.n.-F.n. and D.n.--I.n. stimulation, usually with similar patterns. From this evidence, the effects evoked by the D.n. stimulation on to VL n. neurones seem to potentiate the F.n. and I.n. actions, whereas teh convergent F.n.-I.n. inputs exert often opposite effects on the same neurone. The dorso-medial and the ventro--lateral VL n. regions also seem to receive different actions from the converging cerebellar nuclear outputs. All the results are functionally discussed in terms of a possible integration between posture and voluntary movements at the level of the thalamic relay nucleus of the cerebello-cortical pathway.

Animals↗
PubMed1980

Growth of Yoshida ascites tumor in the rat after radiofrequency destruction of the tuberoinfundibular region of the hypothalamus.

The mitotic index of Yoshida ascites tumor cells was significantly higher in rats that underwent tuberoinfundibular destruction than those lesioned in other regions of the hypothalamus or in the cerebral hemispheres or in sham-operated animals. Survival was shorter in the rats lesioned in the tubero-infundibular and posterior hypothalamic regions. The rise in the mitotic index of Yoshida ascites tumor cells is consistent with the results of previous work showing significantly increased cell proliferation in the normal tissues of animals lesioned in the tuberoinfundibular region.

Acoustic Stimulation↗