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S Berretta

Publications and source records attributed to S Berretta.

36 records · Page 2Linked to original sources
PubMed1991

The cerebellopontine system: an electrophysiological study in the rat.

We examined the effects of electric stimulation of the cerebellar lateral nucleus (LN) in the rat on the activity of single pontocerebellar neurons in the basilar pontine nuclei (BPN) and the reticulotegmental nucleus (RtTg). We found that about half of the cells of these nuclei that were influenced by LN stimulation were inhibited. A significant fraction of both excitatory and inhibitory responses had latencies of less than 4 ms and were able to follow high frequency stimulation, compatible with a monosynaptic linkage. Extracellular field potential recordings within the BPN and RtTg were interpreted as arising from impulses propagating along inhibitory axons projecting in a bundle from the cerebellum to these pontine structures. Microiontophoretic administration of GABA antagonists bicuculline or picrotoxin abolished or attenuated most inhibitory effects. Therefore, we conclude that LN-induced inhibition is most likely mediated by cerebellopontine GABAergic fibers. The functional significance of this cerebellopontine inhibitory circuit is discussed.

Animals↗
PubMed1991

Origin of cuneate projections to the anterior and posterior lobes of the rat cerebellum.

The present study was carried out to analyze the topography of projections from external cuneate nucleus to the anterior and posterior lobes of the cerebellum and to investigate whether projections to the two lobes come from different cuneocerebellar neurons or from branching axons of the same cells. We used retrograde double-labeling techniques to estimate the incidence of cuneocerebellar neurons projecting to both anterior and posterior lobes via axon collaterals. Cells sending their axons to the lobus anterior were about twice the number of those projecting to the posterior lobe. The double-labeled cells were about 1/7 of all labeled neurons and were located mainly in the more lateral half of the nucleus. Therefore, the two lobes of the cerebellum are likely to receive common information from these cells, but different information from the separate populations of cuneocerebellar neurons that project only to one lobe or the other.

Animals↗
PubMed1991

Origin of spinal projections to the anterior and posterior lobes of the rat cerebellum.

The present study was carried out to analyze the topography of spinal projections to the anterior and posterior lobes of the cerebellum and to investigate whether projections to the two lobes come from different spinocerebellar neurons or from branching axons of the same cells. We used orthograde transport of horseradish peroxidase conjugated with wheat germ agglutinin (WGA-HRP) to identify the cerebellar areas where spinocerebellar axons terminate and retrograde double-labeling techniques to estimate the incidence of spinocerebellar neurons projecting to both anterior and posterior lobes via axon collaterals. Orthograde labeling confirmed that the rat, like other mammalian species, has spinocerebellar projections to two different regions of cerebellar cortex, i.e., lobules I-V of the anterior lobe and lobule VIII of the posterior lobe, with the highest incidence in lobules II, III, and VIII. We did not observe a clear difference in the distribution of afferents coming from different spinal segments to either of the two lobes. The double-labeled cells were located primarily in the lower thoracic and upper lumbar segments, almost exclusively in Clarke's column and in the dorso-lateral part of lamina 7 (in the region of the spinal border cells). It is likely that most or all of the spinocerebellar neurons in these structures project to both anterior and posterior lobes. Therefore, the two lobes of the cerebellum are likely to receive common information from these cells, but different information from the separate populations of spinocerebellar neurons that project only to one lobe or the other.

Afferent Pathways↗
PubMed1990

Influence of play on creative thinking.

The immediate influence of flexible and highly structured play on the creative thinking of 184 fourth-grade boys and girls was investigated. Following either flexible or highly structured art, drama, and playground activities, children's performances on the Torrance Tests of Creative Thinking were evaluated. Children who participated in flexible play experiences showed significantly greater creative thinking than children participating in the highly structured play experiences. No significant differences were found between boys and girls related to effects of flexible and structured play on creative thinking. Implications for curriculum are explored.

Child↗
PubMed1989

Projections from the intracerebellar nuclei to the ventral midbrain tegmentum in the rat.

The present study was undertaken to provide anatomical evidence, in the rat, for a direct projection from the cerebellum towards structures, other than the red nucleus, which belong to the ventral midbrain tegmentum, by using the retrograde as well as the anterograde horseradish peroxidase transport method. Following unilateral injection in the ventral midbrain tegmentum of horseradish peroxidase, free or conjugated to wheat germ agglutinin, sparing the red nucleus, retrogradely labeled neurons were found in the contralateral cerebellar lateral nucleus and, at lower density, in the interpositus nucleus. No labeled neurons were found in the fastigial nucleus of either side. Anterogradely labeled axons from lectin coupled horseradish peroxidase injection sites in the lateral and interpositus nuclei reached the contralateral ventral midbrain tegmentum. Terminal labeling was observed in the entire red nucleus as well as in the lateral division of the ventral tegmental area of Tsai, in the dorsal region of the substantia nigra pars compacta, and in the medial part of the retrorubral field. No terminal labeling was found in the caudal linear nucleus, interfascicular nucleus, peripeduncular nucleus, rostral linear nucleus of the raphe, substantia nigra pars lateralis and the substantia nigra pars reticulata. Terminal labeling was also not observed in the ventral midbrain tegmentum following horseradish peroxidase injection in lateral and interpositus nuclei of rats pretreated with kainic acid. In conclusion, it is noteworthy that, besides the red nucleus, the sole structures of ventral midbrain tegmentum receiving cerebellar efferents are those with a higher density of dopaminergic cells.

Animals↗
PubMed1988

Interleukin 2 modifies the bioelectric activity of some neurosecretory nuclei in the rat hypothalamus.

Introduction of 15-30 U of interleukin-2 (IL-2) into the 3rd ventricle of Wistar rats was followed by a marked and significant decrease in neuron discharge frequency in the ventromedial nucleus of hypothalamus and a marked increase in the supraoptic and paraventricular nuclei. The monoclonal antibody ART62 partly blocked these effects. The conventional anti-IL-2 receptor monoclonal antibody ART18 had only a non-significant influence on the effects of IL-2. Since the supraoptic and paraventricular nuclei secrete the antidiuretic hormone, their excitation may offer a partial explanation of the considerable water retention observed during IL-2 therapy against neoplasia.

Action Potentials↗
PubMed1987

Basal ganglia influences on the cerebellum of the cat.

The changes in firing rate of intracerebellar nuclear neurons following electrical stimulation of the contralateral basal ganglia were investigated in adult cats, in which antidromic activation of cortico-pontine and/or cortico-olivar fibers arising in the area 6 had been excluded by chronic ablation of the motor cortex. Activation of putamen and caudate nucleus induced discharge changes in a low percentage (below 12.5%) of both medial and lateral cerebellar nuclei neurons, while stimulation of globus pallidus and especially of entopeduncular nucleus modified the spontaneous discharge of a greater percent of cells (up to 29%), mainly in the most lateral cerebellar portions. The basal ganglia-induced effects were abolished upon section of the brachium pontis but not of the restiform body. Latency values of the responses, which were predominantly excitatory in nature, suggest the involvement of structures interposed between basal ganglia and precerebellar systems. We postulated that impulses issued by the basal ganglia could reach the cerebellum through a pathway that involves the pedunculopontine nucleus and the nucleus reticularis tegmenti pontis.

Animals↗
PubMed1984

Altered time course of changes in the hippocampal concentration of excitatory and inhibitory amino acids during kainate-induced epilepsy.

The temporal sequence of electrophysiological and biochemical correlates of epilepsy induced by systemic injection of kainic acid (15 mg/kg i.p.) was investigated in male rats. A significant decrease in the hippocampal concentration of glutamate and aspartate was observed 20 min after the injection. These decreases preceded both electrographic and behavioral manifestations of epilepsy, thus suggesting a causal relationship between acidic amino acid changes and the genesis of kainate-induced hyperactivity. About 30-45 min after kainate injection, a decrease in glutamate, aspartate, glycine and taurine and no change in GABA concentration were observed. Bioelectrical activity, recorded in the regio inferior (CA3) of the hippocampus or in the fascia dentata revealed the presence of high frequency bursts separated by a long-lasting depression of discharge. About 55-75 min after the injection, the number of spikes in each burst increased and the duration and frequency of interictal pauses decreased. This stage was characterized by a decrease in glutamate and aspartate, restoration to normal of glutamine, glycine and taurine and a decrease in GABA.

Amino Acids↗
PubMedDate not supplied

[Sialolithiasis of the submandibular gland: therapeutic options and technical notes].

The Authors report their experience in the surgical treatment of submandibular sialolithiasis, particularly as far as simple sialolithotomy of Wharton's duct and submandibular gland resection are concerned. Care must be taken to minimize the risk of nerve damage (marginal mandibular branch of the facial nerve; lingual nerve; hypoglossal nerve).

Aged↗
PubMedDate not supplied

[Post-thymectomy extrathymic tumors].

The Authors report the case of a 78 year old woman affected with two synchronous primary cancers (epidermoid bronchial and rectal adenocarcinoma); 16 years previously, after the discovery of a thymoma, she underwent thymectomy. Thus, the discussion issue is if post-thymectomy extra-thymic malignancies are to be considered just a simple coincidence or a true syndrome.

Adenocarcinoma↗