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A Fernández-Guardiola

Publications and source records attributed to A Fernández-Guardiola.

At least 19 recordsLinked to original sources
PubMed1992

EEG frequency and time domain mapping study of the cortical projections of temporal lobe amygdala afterdischarge during kindling in the cat.

EEG frequency and time domain color maps were computed during amygdala kindling in cats. The pattern of the amygdala afterdischarge (AM/AD) propagation to the cortex was assessed as kindling evolved. Our results show that the AM/AD has 4 components that coincide with the activation of certain cortical areas during specific behavioral stages. The pattern of the cortical projection follows an asymmetrical temporo-fronto-occipital direction, the ipsilateral temporal lobe being the first activated zone, followed by the ipsilateral and contralateral prefrontal areas. The contralateral temporal activation is a late phenomenon. We conclude that the electrographic and behavioral manifestations of this model of complex partial epilepsy are asymmetrical during the whole process, including the convulsive stage.

Amygdala↗
PubMed1989

Effects of 1 week administration of two benzodiazepines on the sleep and early daytime performance of normal subjects.

This study analyzed the effects of 1 week administration of alprazolam (AL; 0.25 mg), lorazepam (LO; 1 mg) and placebo (PL) on sleep as well as their residual effects on attention upon awakening. Under a crossed, double-blind design, six healthy male volunteer subjects between 19 and 30 years of age were studied. After two habituation sessions and a control session, each substance was given orally, twice a day for 7 days, with a 1-week washout period between administrations. At the end of each administration period, sleep studies were conducted from 2300 to 0700 hours. Evaluation of attention was carried out by means of a simple visuomotor reaction time (RT) task, and a time estimation (TE) task, that started at 0700 hours, lasting 1 h. Neither drug significantly affected any sleep variable. Both benzodiazepines tended to increase RT, but only LO did so significantly at the beginning of the attention test. No significant changes in predictive and failure responses during the RT task were produced by either drug. Also, no significant changes were observed in the TE. Even though only LO produced a significant increase of RT at the selected doses and with 1 week administration, it is suggested that both benzodiazepines could have residual effects on attention.

Adult↗
PubMed1988

Naloxone facilitates sensory precipitation of focal and generalized seizures: evoked potentials and power spectral analysis in the cat.

To analyze the role of endogenous opioids on epileptogenesis the effect of repeated doses of naloxone alone (NA) (2, 4, and 8 mg/kg every 15 min) or along with intermittent photic stimulation (NPS) (1, 3, and 10 Hz) was tested on acute "Encephale isolé" cats. The electrical activity recordings of sensorimotor cortex (SMC), visual cortex, and right and left amygdalae revealed progressive changes as naloxone was administered: (A) slow spindle activity (4-6 Hz) in SMC, (B) 12 Hz rhythmic activity in both amygdalae, (C) generalized paroxysms, and (D) spontaneous tonic-clonic electrographic seizures. These changes occurred in both experimental groups (NA, NPS), and their onset was dose-related. Photic stimulation precipitated these phenomena. The amplitude of the visual evoked potential components (N1-P1, P1-N2, N2-P2) and power spectral analysis of spontaneous and evoked activity underwent progressive changes. Our results confirm a facilitatory effect of naloxone on epileptogenesis and suggest a possible role of endogenous opioids in this process and on sensory pathways' excitability.

Amygdala↗
PubMed1985

Amygdala kindling in totally cerebellectomized cats.

This work describes the effect of total cerebellectomy on the development of kindled seizures produced by daily electrical stimulation of the temporal lobe amygdala. When the kindling was established, the cerebellectomized cats showed an increase in the afterdischarge and in the duration of generalized seizures. Henceforth, this duration increased persistently in the experimental cats, whereas it did not in the controls. Prior to the establishment of generalized seizures, no kindling behavioral stages or EEG differences were observed between experimental and control cats, despite the motor activity in the cerebellectomized cats being associated with persistent ataxia. In these animals there was also an increase in postictal EEG spikes after the establishment of generalized seizures. We conclude that total cerebellectomy induces anatomical and functional changes in the brain stem structures (mainly in the inferior olive and red nucleus) leading to a facilitation of tonic-clonic neocortical activity.

Amygdala↗
PubMed1985

Effects of clonidine in narcolepsy.

The antihypertensive drug clonidine was given in an open trial to two treatment-resistant (psychostimulants and tricyclic antidepressants) narcoleptic patients. When given acutely, clonidine suppressed REM sleep. However, patients became tolerant after repeated doses but did not lose the drug's beneficial clinical effects. This suggests that REM suppression may not be necessary for improvement in narcolepsy. Assessments of both clinical and polysomnographic variables before and after the trial indicate that clonidine may have a place in the treatment of some patients with narcolepsy.

Adult↗
PubMed1979

Petit mal and grand mal seizures produced by toluene or benzene intoxication in the cat.

Motor incoordination, euphoria and hallucinations are symptoms reported for humans voluntarily intoxicated by industrial solvents. An epileptic-like consciousness impairment has also been noted. The present paper describes a technique used for the experimental study of solvent intoxication in which toluene and benzene can be applied directly into the trachea of freely moving cats with chronically implanted electrodes. This technique permits the control of solvent dose and time of exposure. Results showed a 3 Hz spike-wave activity in the gyrus cinguli recording with both toluene or benzene intoxication. Furthermore, benzene inhalation produced generalized tonic-clonic seizures. These effects were dose-related. However, a sensitization period was essential for the development of such alterations, and effects showed a tendency to shortening through chronic exposures. These alterations were correlated with behavioral disturbances such as nodding, twitching and apparent hallucinations. Results are discussed regarding the sensitization period, the optimal peak of effects, and the period of tolerance development relevant to an earlier found amygdalar activation that could be correlated with other methods inducing experimental seizures, such as repetitive stimulation of the brain (kindling).

Amygdala↗
PubMed1979

Effects of diphenylhydantoin on the spontaneous activity of Purkinje, nucleus interpositus, red nucleus and motor cortex cells.

(1) Extracellular multiunit recordings were made of the spontaneous activity in cerebellar Purkinje cells, nucleus interpositus, red nucleus and sensorimotor cortex in acute cat preparations. (2) Changes in this spontaneous neural activity produced by the administration of diphyenylhydantoin (DPH) were studied. DPH was infused i.v., generally at a concentration of 2.5 mg/ml and at a rate varying from 0.08 to 0.48 mg/kg/min. Two different patterns of infusion were used: fixed time, variable rate and variable time, fixed rate. Pulsed doses were also given at intervals of 5--10 min. (3) DPH at a level of 10--20 mg/kg produces a significative initial deceleration in all structures followed by a significative acceleration in the Purkinje cells, nucleus interpositus and red nucleus as a dose of 20--30 mg/kg is reached. Higher levels caused a profound depression of multiunit activity. (4) The activation produced by DPH is oscillatory (3--5/min) in character and is composed of 'trains' which occur at a rate of 20--30/sec with very rapid discharge frequencies (600--800 Hz). (5) A direct significant correlation was found between DPH serum levels and the intravenously administered dose. The activating DPH dose (20--30 mg/kg) corresponded to serum levels of 24--32 micrograms/ml. (6) The possibility is discussed whether the anticonvulsant action of DPH may be due in part to the production of rhythmic oscillatory activity in the cerebello-rubro-olivo-cerebellar ciruit and the depression of the cerebellothalamic-cortical pathway.

Animals↗
PubMed1977

[Man and time].

Explore the source record for details and available documents.

Concept Formation↗
PubMed1976

Neuroendocrine and electroencephalographic sleep changes due to acute amphetamine ingestion in human beings.

Amphetamine, a clinically used sympathomimetic central-acting drug, was administered in Spansule capsules in a blind schedule to 8 normal obse volunteers in a daily (8 a.m.) single 15 dose for 7 days. The study, conducted in the metabolic ward, included two 7 day placebo periods (pre- and post-drug). During the 1st placebo period, all subjects exhibited within the 1st 2 h of sleep a clear and significant nocturnal increase of growth hormone (GH) closely related with sleep stages 3 and 4. Thyrotropin (TSH) increase was observed between 01.00 to 04.00 h and was accompanied by a reduction of thyroxine (T4) levels. Cortisol levels presented their characteristic rhythm, clearly associated with paradoxical sleep (REM). Amphetamine significantly reduced stages 3 and 4, as well as REM sleep, and increased stage 2. GH and cortisol circadian profiles were preserved, although their magnitude was diminished. The extent of nocturnal TSH and T4 changes was significantly reduced. Drug withdrawal was accompanied by a rebound of REM sleep and a trend to recover the pretreatment TSH and T4 temporal profile. These results suggest that adrenergic neurotrasmitters may be a significant modulating system for TSH and cortisol, whereas GH nocturnal secretion may be influenced by different mechanisms.

Adolescent↗