The relationship between unitary and mass cortical responses to peripheral stimulation in the anaesthetised rat

Angel, A.; Unwin, J

doi:10.1016/0024-3205(68)90235-x

Cited by 4 publications

(14 citation statements)

References 5 publications

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“…an increased probability of response, an alteration in the scatter of the latency or its mean value. Some of the changes we observed were similar to those described by Angel & Unwin (1968) SOCIETY, MARCH 1969 changes in firing pattern were not observed in all units whose shortlatency response was altered during strong stimulation. All the units were found within the primary somatosensory receiving area.…”

Section: C-2 51psupporting

confidence: 88%

Proceedings of the Physiological Society, 21–22 March 1969, University College London Meeting: Demonstrations

1969

The Journal of Physiology

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The apparatus demonstrated was designed to improve the precision of the methods used for the collection, manipulation and analysis of very small uncontaminated specimens of the inner ear fluids of the rat and for the measurement of the endolymphatic potentials in the same animals.To eliminate risk of deterioration in the animal's condition all the microdissection, electrical measurements and fluid collections were completed in both ears within 1 hr, making operative speed vital. These manipulations were greatly facilitated by the firm fixation of the head provided by a specially designed claw clamp, giving a firm four-point grip upon the edges of the bony plate connecting the superior margins of the orbits. The clamp was securely mounted in an arrangement of gimbals with their axes traversing the cochlea. With this positioned at the point of focus of the microscope it was easy to impart to it the critical orientations required.The recording and aspirating micropipettes were mounted upon a small micromanipulator carried upon an engineer's flexible snake-arm, by means of which the first coarse positioning of the pipette could be carried out with speed and accuracy. In order to make the clamp for the fixation of this snake-arm virtually dead-beat it was necessary to apply considerable tension to the central Bowden cable, leading to frequent avulsion of the terminal nipples. A novel method of construction was therefore devised which greatly increased the strength of these junctions.Satisfactory fluid specimens were subdivided into samples, generally 2 nl. in volume, for analysis and each sample diluted with 1 #1 of distilled water, enabling it to be stored in a silica pipette for periods of up to 7 days. To prevent contamination all these manipulations were carried out under C

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Section: C-2 51psupporting

confidence: 88%

Proceedings of the Physiological Society, 21–22 March 1969, University College London Meeting: Demonstrations

1969

The Journal of Physiology

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“…Bilateral representation was only found for receptive fields on the teeth and face. There would thus appear to be considerable disparity between the results obtained from evoked potential and single unit studies, despite the close correlation that might be expected from these two methods of investigation (Angel & Holmes, 1967;Angel & Unwin, 1968).…”

Section: Discussionmentioning

confidence: 99%

“…3). The amplitude of the N1 wave is increased by up to 10 times after catechol administration and Angel & Unwin (1968) have shown that if the N1 wave increases in amplitude, the discharge probability of cortical cells responding with a short latency to peripheral stimulation also increases. These 'N1 cells' are located in the superficial layers of the cortex (0.35-1.2 mm below the surface), have small receptive fields and cannot be discharged antidromically by pyramidal tract (PT) stimulation.…”

Section: Discussionmentioning

confidence: 99%

Sensorimotor cortical representation in the rat and the role of the cortex in the production of sensory myoclonic jerks.

Angel¹,

Lemon²

1975

The Journal of Physiology

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SUMMARY1. After administration of 1,2-dihydroxybenzene (catechol) to anaesthetized rats, rabbits and cats, a reflex jerk consisting of three distinct components was evoked in the limb muscles by peripheral stimulation. The second component of the jerk in the forelimb muscles of all three animals was specifically abolished by lesions confined to the contralateral forelimb sensorimotor cortex.2. These lesions had no effect on the second response in either the hind limbs or in the forelimb ipsilateral to the lesion. The first and third responses were also unaffected.3. Lesions in the cat hind-limb cortex abolished the contralateral hind-limb second response, but not the ipsilateral hind-limb or forelimb response.4. In the rat and rabbit, unilateral hind-limb sensorimotor lesions were ineffective in completely abolishing the second response in the contralateral hind-leg muscles, and in addition, reduced the probability of occurrence of the response in the ipsilateral hind leg. Bilateral lesions abolished the response.5. Re-investigation of the sensory and motor representation of the hind limb in the rat cortex revealed that this is bilateral in nature. Shortlatency cortical responses (ca. 7*0 msec) could be evoked in one cortex by stimulation of either hind paw. The geometric centre of the cortical area from which these responses could be recorded was identical for each hind paw.6. After catechol injection, stimulation of the cortical surface with single anodal shocks of threshold strength produced responses at similar latency (ca. 8f0 msec) in both hind limbs.7. The behaviour of the second response after cortical lesions corresponds A. ANGEL AND R. N. LEMON closely with the pattern of the somatosensorimotor cortical representation. The latency of the response is such as to allow its production by a long-loop cortical reflex, and this possibility is discussed.

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“…1973 ), was not significantly altered by Etomidate. Ni, however, which has been suggested to reflect the cortical response to the arrival of the afferent volley ( Angel & Unwin 1968), was depressed in a dose‐dependent manner. Thus, both single cell and mass response records indicate that Etomidate perturbs evoked cortical behaviour in the absence of a corresponding change at the thalamic level.…”

Section: Discussionmentioning

confidence: 99%

“…After an initial latent period of 4±6 ms, peripheral stimulation is followed by an initial positive in¯ection in the mass response (Pi) and, thereafter, by an initial negative in¯ection (Ni). The amplitude of Pi is related to the magnitude of the thalamocortical volley (Angel et al, 1973), while the size of Ni re¯ects the extent of the cortical response to the arrival of the volley (Angel & Unwin, 1968). A reduction in ventroposterolateral thalamic cell responsiveness is accompanied therefore by an increase in the latency and reduction in the amplitude of Pi, while a decrease in the amplitude of Ni corresponds to a diminution in primary somatosensory cortical cell responsiveness.…”

Section: Introductionmentioning

confidence: 99%

The effect of Etomidate on sensory transmission in the dorsal column pathway in the urethane‐anaesthetized rat

Angel

Arnott

1999

Eur J of Neuroscience

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The effect of Etomidate, a general anaesthetic, on sensory afferent transmission was measured in the dorsal column pathway in urethane-anaesthetized rats. Extracellular recordings were made of peripherally evoked responses by single cells in the cuneate nucleus, ventroposterolateral nucleus of the thalamus and laminae IV-VI of the primary somatosensory cortex. Cortical mass responses were also recorded. In further experiments, cortical mass responses were evoked antidromically by stimulation in the pyramidal tract. The effect of incremental administration of Etomidate on evoked responses was recorded. These results are compared with the previously reported effects of urethane, a 'conventional' anaesthetic. Etomidate did not alter cuneate or ventroposterolateral thalamic cell responses but it caused a dose-dependent reduction in cortical cell responsiveness. It failed to alter antidromically evoked cortical mass responses. Etomidate differs from the majority of anaesthetics, which act in the thalamus, and appears to cause perturbation at the cortical level.

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The relationship between unitary and mass cortical responses to peripheral stimulation in the anaesthetised rat

Cited by 4 publications

References 5 publications

Proceedings of the Physiological Society, 21–22 March 1969, University College London Meeting: Demonstrations

Proceedings of the Physiological Society, 21–22 March 1969, University College London Meeting: Demonstrations

Sensorimotor cortical representation in the rat and the role of the cortex in the production of sensory myoclonic jerks.

The effect of Etomidate on sensory transmission in the dorsal column pathway in the urethane‐anaesthetized rat

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