Facilitation Et Inhibition Des Potentiels Évoqués Corticaux Dans L'éveil Cérébral

Bremer, F; Stoupel, N

doi:10.3109/13813455909074432

Cited by 122 publications

(28 citation statements)

References 18 publications

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“…The fact that potentiation appears only after transection of the brain stem leads to the assumption that the transection eliminates ascending tonic inhibiting influences from below the level of the lesion and possibly also leads to an increased action of facilitatory connexions from above the lesion level. This assumption is supported by the observations of Bremer & Stoupel (1959) which show that stimulation of the mesencephalic reticular formation facilitates the secondary response, although this effect was obtained only by concurrent electrical stimulation of the optic pathway.…”

Section: Discussionmentioning

confidence: 57%

Inhibitory influences on primary and secondary cortical photic potentials originating in the lower brain stem

Armengol¹,

Lifschitz²,

Palestini³

1961

The Journal of Physiology

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In a recent communication (Palestini, Lifschitz & Armengol, 1959), a study of the habituation of primary and secondary cortical photic potentials in cats which had been subjected to a mid-pontine pre-trigeminal transection was reported. E.e.g. recordings of these evoked potentials after the transection showed a definite lengthening of the period of time in which the primary cortical photic potentials would attain habituation. This lengthening was even more striking in the secondary cortical photic potentials, since normally they reach habituation in a very short time.To explain these results it was suggested (Palestini & Lifschitz, 1959) that an inhibitory influence, arising in structures situated below the level of the lesion, was being exerted. The present paper presents results, obtained in preparations with a mid-pontine pre-trigeminal section, on the changes of the photically evoked cortical potentials, which give additional support to this hypothesis. METHODSFifty cats were used in these experiments. After anaesthesia with sodium pentobarbitone, extradural monopolar stainless-steel electrodes were implanted on the suprasylvian gyrus, on the gyrus lateralis and gyrus lateralis anterior.Control recordings were taken from these animals, non-anaesthetized, at least 5 days after implantation. The light stimulus in all experiments consisted of flashes at a rate of one per second from a Grass PS 1 photic stimulator. To ensure relatively constant stimulation of the retina the light source was always held at the same distance from the eyes, the animal was slung in a hammock and head excursions were restrained by an aluminium cone. All cats were dark-adapted at the beginning of each experiment and their pupils dilated with homatropine. Satisfactory isolation from outside sounds was achieved in all experiments. As a further means of ensuring a constant stimulus to the retina, the nictitating membranes were removed and the facial nerves were divided in some animals.Both monopolar (with an indifferent electrode on the frontal sinus) and bipolar electrodes were used and the electrical changes were recorded by a Grass e.e.g. machine on paper or photographed from an oseilloscope trace. In the latter method successive cortical responses were superimposed on the same picture.

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Section: Discussionmentioning

confidence: 57%

Inhibitory influences on primary and secondary cortical photic potentials originating in the lower brain stem

Armengol¹,

Lifschitz²,

Palestini³

1961

The Journal of Physiology

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“…Iwama & Yamamoto (1961) have shown that if the sensory cortex is removed the thalamic potentials recorded after a peripheral stimulus are increased in size. Dumont & Dell (1958) and Bremer & Stoupel (1959) have reported that the response of the visual cortex to stimulation of the optic nerve was increased while stimulating the reticular formation, and this effect they believed to be due more to a change in the responsiveness of the cortex than to a change in afferent transmission.…”

Section: Discussionmentioning

confidence: 99%

The facilitation of thalamic and cortical responses in the dorsal column sensory pathway by strong peripheral stimulation

Angel¹,

Dawson²

1963

The Journal of Physiology

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During the course of investigations into the variations of the cortical responses to somatic stimuli of constant size, it was found (Dawson, Podachin & Schatz, 1959, 1963 that certain parts of the cortical response to a test stimulus could consistently be increased if the animal was pinched, rubbed or stimulated electrically on any part of the body surface before the test stimulus was applied. These authors showed that the increase in the cortical responses produced by the conditioning stimuli was not accompanied by any corresponding increase in the voltage of the mass potentials recorded from the cuneate nucleus. Evidence will be presented which shows that in similar conditions in the anaesthetized rat stimuli which increase the size of the cortical responses also increase the size of the mass potentials recorded from the sensory pathway in the thalamus. When the cerebral responses and the thalamic mass potentials are increased in size, certain units in the thalamus show an increased probability of firing and show a reduced latency. A preliminary account of part of this work has already appeared elsewhere (Angel & Dawson, 1961). METHODS 120 Albino rats were used for these experiments. No premedication was used. After anaesthetization either with 25 % ethyl carbamate (Urethane) solution in 0-9 % saline injected intraperitoneally, or with a mixture of air and trichloroethylene vapour by inhalation, a tracheal cannula was inserted. The depth of anaesthesia was adjusted by trial and error so that the animal would just not withdraw its hind paw when it was pinched hard. With urethane the amount of anaesthetic required was between 1-3-1-5 g/kg body weight. Access to the cerebral cortex and the thalamus was effected by an extensive craniotomy on one side, usually the left. The dura mater was opened. The head of the animal was held by a plug in each external auditory meatus and by a bar underneath the hard palate behind the * M.R.C. scholar.t On leave from the M.

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“…The volleys of the initial impulses evoked by the photic stimulus will 2) Electrically evoked cortical response. Bremer and Stoupel (1959) and Bremer (1961) found that the effects of reticular arousal upon the evoked cortical response varied depending upon the stimulus modality. When a 'peripheral' photic test stimulation was applied to the retina, the evoked cortical response was depressed strikingly by the RF-stimulation.…”

Section: ) Electrically Evoked Response Light-potentiation and Re-smentioning

confidence: 99%

Reticular Stimulation and the Light-adapted Discharges of the Visually Evoked Cortical Response in Cat

Suzuki

Jacobson

1971

Tohoku J. Exp. Med.

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Facilitation Et Inhibition Des Potentiels Évoqués Corticaux Dans L'éveil Cérébral

Cited by 122 publications

References 18 publications

Inhibitory influences on primary and secondary cortical photic potentials originating in the lower brain stem

Inhibitory influences on primary and secondary cortical photic potentials originating in the lower brain stem

The facilitation of thalamic and cortical responses in the dorsal column sensory pathway by strong peripheral stimulation

Reticular Stimulation and the Light-adapted Discharges of the Visually Evoked Cortical Response in Cat

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