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Biomedical subjects

S Roux

Publications and source records attributed to S Roux.

At least 163 records · Page 9Linked to original sources
PubMed1987

Auditory evoked responses and their modifications during conditioning paradigm in autistic children.

Auditory evoked responses (AERs) were recorded from 16 autistic children (ages 2-10 years) and age-matched normal and retarded controls. In order to test the ability to form auditory-visual cross-modal associations, often impaired in autism, the effects on AERs of coupling sound and light were studied with a paradigm that did not require the cooperation of the subject. Several differences between groups were found concerning the frequency and the amplitudes of present AERs. The pattern characterizing the effects on AERs of coupling sound and light (conditioning phenomenon) was observed for both autistic and normal controls, and not for retarded children. Results suggest that autistic children may have a real but slow learning ability.

Acoustic Stimulation↗
PubMed1987

[EEG spectral analysis in sylvian ischemia with normal value tracings].

The EEG power spectral analysis of 8 patients with a definite sylvian ischemia, the standard EEG of which was normal, was determined in comparison with the date of a control group (N = 14). We calculated the right-left power spectral differences in 4 symmetrical bipolar leads for 5 rhythms (delta: 1.2-3.1 Hz, theta: 3.5-7 Hz, alpha: 7.4-12.3 Hz, beta 1: 12.9-14.1 Hz and beta 2: 15.2-17.2 Hz). For each patient, the spectral difference is measured in comparison with the normal range of the control group with an alpha risk of 5%. There are 54 asymmetries favouring the lesioned side (mostly in 5 patients) and 6 the opposite, without predominance of a particular rhythm with the exception of the beta 2 rhythm which presents no asymmetries.

Aged↗
PubMed1985

Frontal auditory evoked potentials and augmenting-reducing.

Auditory evoked potentials (AEPs) to tones (750 Hz--200 msec) ranging from 50 to 80 dB SPL were studied at Cz and Fz leads in 29 normal adults (15 males) ranging in age from 20 to 22. Peak-to-trough amplitudes were measured for the P1-N1 and the N1-P2 wave forms as well as baseline (500 msec prestimulus)-to-peak amplitudes for each component, i.e., P1, N1 and P2. Amplitudes were examined as a function of intensity and electrode location. Cz-Fz amplitude differences increased with increasing stimulus intensity, the differentiating peak being the N1 component. An overall reducing phenomenon was found at Fz in the 70-80 dB range whereas an augmenting effect was observed at Cz for these intensities. The augmenting/reducing groups defined by analysis of individual amplitude-intensity patterns were different whether we considered Fz or Cz results: Fz reducers were more numerous than Cz reducers. These results on prominent reducing at the frontal level were examined in relation to the data concerning the modulatory function of the frontal cortex on auditory EPs. Implications were drawn for the role of the frontal cortex in cortical augmenting-reducing.

Adult↗
PubMed1985

[Study of early somatosensory evoked potentials by stimulation of the median nerve at the wrist in 6 patients with unilateral thalamic lesions].

Somatosensory evoked potentials were recorded at Erb's point, over the cervical spine (C7) and over the cortex: parietal and frontal electrodes were contralateral and ipsilateral to the stimulus which was applied on the median nerve at the wrist. The stimulation was performed on 2 control groups, the first consisting of 10 subjects (average age: 33.6 years), the second of 16 subjects (average age: 66.2 years) and on 6 patients presenting unilateral thalamic lesions. These lesions were circumscribed, ischaemic or haemorrhagic and were visualized by a scanner. In 5 of our patients, a diffusion of the P14 wave with normal latency and a delay in the N20 cortical wave was obtained at the parietal electrode contralateral to the stimulus and homolateral to the lesion. Normal latencies were observed for the diffusion of the N18 wave recorded at the frontal electrode contralateral to the stimulus. In the 6th patient, the evoked potentials were normal. The results of the somatosensory evoked potentials observed in our patients are discussed in the context of the anatomical lesions.

Adult↗
PubMed1984

Discrimination of the amphetamine cue. Effects of A, B and mixed type inhibitors of monoamine oxidase.

Rats were trained to discriminate between the effects of 0.6 mg/kg of (+)-amphetamine given intraperitoneally saline in a two-lever operant task, according to a fixed ratio ( FR10 ) schedule of food reinforcement. Once trained (greater than 90% responding on the appropriate lever during sessions with drug and saline, respectively over 2 weeks), they were given tests of generalization with various type A, type B or mixed type monoamine oxidase inhibitors (MAOI). Generalization was tested during the first 100 sec of a 15 min trial during which no reinforcements were given (extinction) followed by reinforcement on both levers for the rest of the session. Generalization to amphetamine was estimated using both the percentage of responding on the "drug lever" and a measure of choice of lever. None of the type A MAOI's tested [ cimoxatone (MD 780515), clorgyline, LY 51641, moclobemide (Ro 11-1163), toloxatone] showed generalization towards the lever for amphetamine. Clear or partial amphetamine-like responding was observed with the B type MAOI (+/-)-deprenyl and LY 54761 but not with two other type B MAOI's MD 240928 or pargyline. (+/-)-Tranylcypromine, but not nialamide (mixed type MAOI's), induced dose-dependent responding on the lever for amphetamine. It was concluded that amphetamine-like activity was not an intrinsic property of A or B type MAOI's.

Amphetamine↗
PubMed1984

Effects of imipramine on separation-induced vocalizations in young rhesus monkeys.

Three Rhesus monkeys were removed from their mothers at birth and reared together in a group cage. When they were one year old they were subjected to repeated separations during which they were placed alone for 1 hour in another cage in an acoustically isolated adjacent room. The number of vocalizations and gross body movements were recorded automatically. Single injections of imipramine (3.75, 7.5 and 15 mg/kg IM) instead of decreasing tended to increase the number of vocalizations without affecting motor activity. A similar pattern was observed when imipramine (3.75 and 7.5 mg/kg IM) was administered repeatedly (2 injections/day/4 days). The failure of imipramine to decrease separation-induced vocalizations in our conditions suggests that the procedure would not be useful for testing potential antidepressants.

Animals↗
PubMed1984

Habituation of exploratory activity in mice: effects of combinations of piracetam and choline on memory processes.

The effects of various piracetam + choline combinations on an experimental model of memory were investigated. Mice were given two sessions in a simple photo-cell activity cage and the decrease in activity at the second session (habituation) served as an index of retention. Retention was facilitated by post-session administration of 2000 mg/kg piracetam IP and 50 mg/kg piracetam + 50 mg/kg choline IP. Similar injections of choline alone (10 to 200 mg/kg IP), piracetam alone (10 to 1000 mg/kg IP) or other combinations of piracetam and choline were without effect. These results, consistent with those reported elsewhere, suggest that piracetam can interact with choline to facilitate memory processes in mice.

Animals↗
PubMed1984

Are there sex differences in averaged evoked responses produced by coupling sound and light in children and adults?

Averaged evoked response (AER) amplitudes have been reported to be larger in women than in men. The aim of this study was to determine whether AER changes produced by coupling sound and light differed between males and females (adults and children). Given the 3:1 male-female ratio in early infantile autism, we reasoned that information about sex-related differences in normal subjects might be important in interpreting the results in autism. We observed the characteristic AER changes when coupling sound and light: increased response amplitude over the occiput for both adults and children, decreased response amplitude over the vertex for adults and N1 decreased and P2 increased response amplitude over the vertex for children. Differences appeared as a function of sex in adults: the number and the amplitudes of AERs recorded in women were greater than in men with the exception of the P2 peak recorded over the occiput which was similar for males and females. The sex-related differences observed in the number and amplitudes of AERs are reduced when coupling sound and light.

Acoustic Stimulation↗
PubMed1984

[Brain stem auditory evoked potentials in the normal and autistic child].

From a neurophysiological viewpoint a hypothesis for the etiology of early infantile autism suggests that the symptoms are a result of abnormalities in processing sensory input at the level of the brain-stem. The methods for recording auditory evoked responses (BAERs) seemed particularly well suited to study a failure at this level. BAERs to brief monaural and binaural stimulation were studied in 17 autistic children ranging in age from 3 to 9 years (mean = 6.1). They were age and sex matched to normal controls. Electrodes were placed at the vertex and at the mastoid ipsilateral to the stimulation. Signals were amplified 10(5) using an amplifier with bandpass filters set at 160 Hz and 3 kHz. Stimuli were clicks (120 microsec) delivered to subjects through earphones at 2 intensities: 70 and 90 dB. Stimuli were presented in blocks of 3000 clicks (1500 clicks for each intensity) with a rate of 10/sec. No sedative medication was used. There was no difference between autistic and normal children for the latencies of peak I. Latencies of peaks II, III, IV and V were found to be shorter in autistic than in normal children. The I-II and II-III interpeak transmission times were significantly decreased in the autistic group, but not III-V interpeak transmission time. Autistic children showed V-VN amplitude greater than normal children. Our findings suggest that in the autistic syndrome, there is a defect of the modulation processing input related to intensity at brain-stem level.

Autistic Disorder↗
PubMed1984

[Frontal evoked potentials and sensitivity to methylphenidate. Individual differences].

Auditory evoked potentials (AEPs) were recorded from 2 sites (Cz and Fz) on 17 subjects while awake. Five sound intensities were used (40-50-60-70-80 dB). Regression slopes relating AEP amplitude (N1-P2 component) to stimulus intensity were used to describe augmentation or reduction (A/R) of amplitude with increasing intensity. The individual differences thereby obtained have been related with the individual responsiveness to methylphenidate (MPD) measured by the modifications of polygraphic sleep parameters after absorption of this substance. The sleep parameters were recorded under 3 conditions: N1, night of habituation; N2, reference night (placebo); N3, night after 20 mg of methylphenidate (MPD); nights 2 and 3 consisted of a double blind cross-over. For the placebo condition, the lower the A/R slope while awake (and particularly the Fz slope), the higher the sleep efficiency, with scarcity of nocturnal awakening and precocity of the morning awakening. Individual differences concerning MPD responsiveness measured with sleep parameter modifications are significantly correlated with the frontal A/R slopes: the wakefulness effect of MPD increases as the frontal A/R slope weakens while a paradoxal drowsiness effect is observed at the other extreme (frontal augmenters). Moreover, sleep modifications due to the first night effect show similarities with those due to MPD and are correlated in the same way with frontal A/R slopes.

Adult↗
PubMed1984

Prostaglandin E1 increases myocardial contractility in the conscious dog.

The systemic and inotropic properties of prostaglandin E1 (PGE1) were investigated in 20 unanesthetized dogs. Pairs of ultrasonic dimension gauges and a micromanometer were implanted in the subendocardium and the apex of the left ventricle (LV), respectively. Seven to ten days later, increasing doses of PGE1 were infused into the left atrium. To appreciate the inotropic effects of the agent, the heart rate was maintained constant at 150 beats/min in a subgroup of dogs while preload was modified by bleeding or saline infusion over matched ranges of end-diastolic segmental length (EDL) during placebo and PGE1 infusions (0.25 microgram . kg-1 . min-1). LV function curves (delta L: systolic segmental shortening versus EDL) were plotted. Increasing doses of PGE1 above 0.031 microgram . kg-1 . min-1 brought a progressive decrease of left ventricular end-diastolic pressure, EDL, delta L, and peak left ventricular systolic pressure. The heart rate increased significantly at dosages from 0.063 to 0.125 microgram . kg-1 . min-1, and peak positive dP/dt after an initial increase fell at the dose of 0.5 microgram . kg-1 . min-1. The LV function curves invariably showed a shift to the left when PGE1 was administered; as the basal EDL was restored during PGE1 infusion, delta L reached a 33% increase (p less than 0.001). Thus, in addition to its potent vasodilating properties that are more prominent on preload than afterload, PGE1 increases myocardial contractility in the conscious dog.

Alprostadil↗
PubMed1983

Influence of waking and sleep stages on the inter-ictal paroxysmal activity in partial epilepsy with complex seizures.

Twenty-six patients suffering from partial epilepsy with complex seizures underwent polysomnographic recording. Paroxysmal activity (PA) densities in waking and sleep stages were assessed. Total PA densities of one night were found to be an increasing function of the seizure frequency in the previous period. Nineteen patients had more PA during sleep, 5 others in the waking state and the two remaining patients exhibited no differences in PA densities between sleep and waking. Nocturnal seizures were reported by patients showing the sleep PA increase pattern; they also used more anti-convulsants than patients showing the waking PA increase pattern. Differences in PA densities between these two groups were more pronounced in the more desynchronized (waking) and the more synchronized (stages 3 + 4) cortical states. The modulation by slow wave sleep stages was independent of, and superimposed on, the sleep/waking one.

Adolescent↗
PubMed1983

[Paroxysmal nocturnal activity in partial epilepsy in the adult].

Thirty-four adults with partial epilepsy underwent polysomnographic sessions. Three sub-groups of patients were determined by timing their EEG paroxysmal activities (PA) according to the possible increase in PA related to their sleeping or awake state. Twenty-seven had an increase in PA when sleeping, 5 when awake and no significant difference was found in two other patients. Patients who suffered from nocturnal or partial elementary epileptic seizures were those who showed a PA increase when in a sleep state. These patients had a lower PA density during a waking state than the patients with a PA increase when awake. The more synchronized (stages 3 + 4) and desynchronized (waking) cortical states influence the PA densities in such a way that there is a significant difference between both sub-groups. The PA density modulation found with the slow-wave sleep stages adds to that induced by sleep and waking states.

Adolescent↗