Influence of respiratory afferents upon the proprioceptive reflex of skeletal muscles in healthy humans.

Relationships between respiratory afferents and the motor drive to skeletal muscles are well documented in animals, but human data are scarce. Tonic vibratory response (TVR) elicited by mechanical tendon vibrations were explored in an arm (extensor digitorum, ED) and a leg (vastus lateralis, VL) muscle, in healthy subjects. Tendon vibrations were delivered during unloaded breathing and after 10 breathing cycles while the subject breathed through an inspiratory or expiratory resistive load in order to activate respiratory afferents.

Resistive loaded breathing changes the motor drive to arm and leg muscles in man.

Breathing through inspiratory or expiratory resistive loads activates respiratory afferents. In healthy individuals, we explored the recruitment of motor units in arm (adductor pollicis, AP and biceps branchialis, BB) and leg (vastus lateralis, VL) muscle groups during voluntary contractions sustained at 80% of maximal force. Quantitative EMG analysis consisted of measurement of energies in high (EH) and low (EL) frequency bands.

Bilateral and side-related reaction time impairments in patients with unilateral cerebral lesions of a medial frontal region involving the supplementary motor area.

Human subjects (nine patients with unilateral brain lesions of a medial frontal region involving the supplementary motor area, SMA, and 10 controls) performed two reaction time (RT) tasks in response to the presentation of a luminous signal: an aimed movement towards a spatially defined target involving hand lifting and pointing with the index finger, and a no-aimed movement consisting of the hand lifting phase completed by the stabilization of the limb posture without any pointing. When compared with controls, the patients exhibited a bilateral RT increase which was more pronounced in the hand contralateral to the lesion. Moreover, comparison between the two tasks showed that this contralateral RT impairment was more marked in the no-aiming than in the aiming task.

Long-term serotonin reinnervation of the suprachiasmatic nucleus after 5,7-dihydroxytryptamine axotomy in the adult rat.

We present here immunohistochemical evidence that serotonin (5-HT) reinnervation in the suprachiasmatic nucleus (SCN) of adult rats, after intraventricular administration of 5,7-dihydroxytryptamine, is more extensive than formerly believed. The first fibers appeared at 4 months and developed until more than 7 months. However, comparison with age-matched controls showed that, even 24 months post-lesion, the density of 5-HT innervation remained abnormally low.

[Neurophysiological study of propofol (2-6 diisopropylphenol): experimental data].

Propofol was assessed in laboratory animals using an experimental technique which leads to an over all appreciation of central nervous system function. After Bimar and Naquet, (1966) a battery of neurophysiological tests in the cat investigate specific primary pathways (visual evoked potentials), non specific pathways (arousal reaction) and hemodynamic response to painful aggression (stimulation of dentine). Propofol appears to be a powerful narco-hypnotic drug.

Putative neurotransmitters in the red nucleus and their involvement in postlesion adaptive mechanisms.

A variety of putative neurotransmitters has been described in the red nucleus (RN). Measurement of neurotransmitter biochemical markers and study of their specific localizations using morphological techniques in lesion and deafferentation of the RN indicate the participation of glutamate (Glu) in corticorubral transmission and the presence of GABA in RN intrinsic neurones. The cerebellorubral projection may contain at least two populations of fibres, the one using acetylcholine and the other Glu as neurotransmitter.

GABA nerve endings in the rat red nucleus combined detection with serotonin terminals using dual immunocytochemistry.

Immunocytochemical methods were used to examine the ultrastructural features and cellular interrelationships of GABA and serotonin afferent fibers to the rat red nucleus. GABAergic nerve endings were identified in two ways, either using a pre-embedding immunoperoxidase procedure with an antibody against glutamate decarboxylase, the GABA-synthesizing enzyme, or after post-embedding immunogold labelling with an anti-GABA antibody. With the latter approach, it was possible to simultaneously visualize the GABAergic and serotoninergic innervation of the red nucleus (magnocellular part) in electron microscope preparations.

Immunohistochemical evidence of plasticity of gamma-aminobutyric acid neurons in the red nucleus and adjacent reticular formation after contralateral cerebellectomy in the adult cat.

A comparative mapping of gamma-aminobutyric acid neurons identified by means of glutamic acid decarboxylase (GAD) immunohistochemistry was performed in the red nucleus (RN) in both intact and hemicerebellectomized adult cats (21 days postoperative). In the deafferented RN (contralateral to the lesion) as well as in the adjacent dorsolateral reticular formation, a marked increase in the number of GAD-positive perikarya was observed. In this mesencephalic area, some neurons may therefore increase their endogenous levels of immunodetectable GAD, as a response to cerebellar deafferentation.

GABA neurons in the cat red nucleus: a biochemical and immunohistochemical demonstration.

Following unilateral kainic acid lesioning of neuronal cell bodies in the cat red nucleus (RN), a large decrease in glutamic acid decarboxylase (GAD) activity was detected in the injected RN, compared to the RN from control, non-injected animals. Using GAD immunohistochemistry, reactive perikarya were visualized dorsolaterally to the rostral part of the nucleus as well as within the RN proper. Taken together, these results point to the existence of an intrinsic GABAergic innervation in the RN area of the cat.

Experimental kuru in Macaca nemestrina: new anatomical data.

In Macaca nemestrina inoculated intracerebrally by a pin-point injection with a strain of kuru Kupenota (2nd passage), the lesions consisted of spongiosis of neuropile with severe astrocytic hyperplasia, located in the grey matter of cerebral hemispheres (cortex, neostriatum). In all cases, the distribution of lesions was asymmetrical, predominating on the side of injection. These results suggest that kuru agent could be replicate around the injection site, but the influence of the host and/or the strain could not be excluded.

[Facilitation of a state of wakefulness by semi-chronic treatment with sulbutiamin (Arcalion) in Macaca mulatta].

Cortical electroencephalographic (EEG) activities and nycthemeral states of vigilance organization were studied in 6 adult rhesus monkeys during subchronic administration (10 days) of Sulbutiamin, a synthesized derivative of thiamine (300 mg/kg/day). Sulbutiamin induced the following modifications: (1) In the EEG activities: increase in occurrence of fast rhythms (over 28 c/sec) during waking and also during slow sleep (SS) in which their amplitude doubled. SS spindles increased in number and amplitude.

[Changes in sleep pattern in presenile and senile dementia (author's transl)].

Analysis of polygraphic recordings of nocturnal sleep in 21 patients with "degenerative" dementia led to the identification of two types of tracing. The first type was characterised by morphologically normal sleep with more marked quantitative changes than those caused by simple aging. In the second type, the criteria of identification of the physiological stages of sleep disappeared, requiring special definition of the E.

[Peculiar and random activity in Macaca: delta rhythm at the vertex].

Despite the fact that waking and sleeping EEG activities are well known in cercopithecinae, a striking random activity was noted in 3 macaque species: M. mulatta, M. fascicularis, M.

Anatomical study of experimental kuru in the Rhesus monkey.

The authors report the morphology and topography of CNS lesions in experimental kuru (third passage) in the rhesus monkey. The main lesions encountered are spongiosis of the neuropile with neuronal vacuolization, moderate astrocytic gliosis, and slight neuronal depopulation. In all cases, lesions predominated in the grey matter of the cerebral hemispheres (cortex, neostriatum).

Experimental kuru in the rhesus monkey. A clinical study.

Serial neurologic examinations of six rhesus monkeys inoculated with a strain of kuru revealed complex clinical signs falling into two distinct syndromes. Experimental kuru in the rhesus monkey is different from the disease in man and to a lesser extent in the chimpanzee. Two factors are proposed to account for these observations: modification of the strain, and specific host characteristics.

Experimental kuru in the rhesus monkey: a study of EEG modifications in the waking state and during sleep.

EEG patterns recorded in the waking state and during sleep were studied in 6 rhesus monkeys inoculated with a strain of Kuru previously passaged in rhesus monkey (ENAGE strain, rhesus L6 56). The onset of the disease was confirmed by the appearance of various clinical signs in 4 monkeys 15 months after inoculation. At the 16th month, the first EEG modifications appeared during sleep, which became lighter.

Appearance of EEG changes reminiscent of a secondary generalized epilepsy in a rhesus monkey inoculated with a strain of kuru.

In a group of rhesus monkeys (Macaca mulatta) inoculated intracerebrally and intravenously with a strain (Enage strain rhesus L6 56) of kuru already passaged in rhesus monkeys, 1 monkey presented the typical EEG pattern of epileptogenic encephalopathy reminiscent of the Lennox-Gastaut syndrome. This observation provides no direct evidence for the viral origin of epilepsies of this type. It does, however, show that it is possible to induce an epileptogenic encephalopathy by an unconventional infectious agent.

[Effects of optic nerve section in baboons on the EEG activity and sleep-waking cycles].

EEG rhythms recorded during the various states of alertness and sleep--waking cycles were studied in 4 baboons before and after optic nerve section. Visual deafferentation induced a general increase in amplitude of all the cortical rhythms, with general accentuation of pre-existing activities such as occipital eye movement potentials (EMPs), the fronto-rolandic rhythm and the alpha rhythm, spindles, REM ponto-geniculo-cortical (PGC) spikes; an increase in amplitude of the geniculate rhythmic activity, its frequency and occurrence was also noticed. When the blind baboons were placed in a monotonous environment, sleep--waking cycles occurred at any time of the 24 h.

[Effects of optic nerve section in baboons on the geniculate and cortical spike activity during various states of vigilance].

Eye movement potentials during wakefulness (EMPs) and so-called spike (PGO) activities were studied in 4 adult baboons before and after optic nerve (ON) section. The latter was performed either in two stages at a 23-day interval or simultaneously. During wakefulness in the intact animal, triphasic EMPs were observed in darkness with smaller amplitude and longer duration than in the light.

[Sleep changes induced by chronic administration of S. 1694 (Survector) (author's transl)].

Five adult Macaca mulatta were studied during chronic administration (24 days) of S. 1694 (10 mg/kg, i.m.

Nonhuman primates: laboratory animals of choice for neurophysiologic studies of sleep.

A systematic study was made of several nonhuman primates to learn more about their relative usefulness for studies of sleep. Species studied included the Guinea baboon (Papio papio), Kenya or yellow baboon (P cynocephalus), olive baboon (P anubis), sacred baboon (P hamadryas), vervet monkey (Cercopithecus aethiops), rhesus monkey (Macaca mulatta), bonnet monkey (M radiata), crab-eating monkey (M fascicularis), patas monkey (Erythrocebus patas), chimpanzee (Pan troglodytes), mongoose lemur (Lemur mongoz), black lemur (Lemur macaco fulvus), and bushbaby (Galago senegalensis). Comparisons were made of electroencephalographic activity, states of vigilance, and responses to sleep-waking drugs.