Properties of Cortical Somatosensory Evoked Potentials in the Awake Rabbit

Colin, Fabienne; Manil, Jacqueline; Bourgain, R.H.

doi:10.1080/01616412.1980.11739557

Cited by 5 publications

(3 citation statements)

References 13 publications

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“…They occurred with time courses that corresponded to the periods of some minutes of stimulation. The site of these changes was always in the appropriate zone of the cortex-parasaggital contralateral parietal cortex for SEPs, and occipital cortex for VERs (Colin et al 1980, Arezzo et al 1988). The magnitude of the changes-a predominant decrease of a few per cent-was similar to those observed during single-channel impedance studies in the limbic system of cats (Adey et al 1962).…”

Section: Discussionmentioning

confidence: 99%

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Imaging of physiologically evoked responses by electrical impedance tomography with cortical electrodes in the anaesthetized rabbit

1996

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The purpose of this study was to determine if electrical impedance tomography (EIT) could be used to image impedance changes of several per cent over tens of seconds, known to occur during evoked activity of the cerebral cortex. A ring of 16 electrodes was placed on the exposed superior surface of the brain of anaesthetized rabbits. EIT images were acquired every 15 s using a Sheffield Mark 1 EIT system. During periods of 2.5-3 min of intense photic stimulation of both eyes or electrical stimulation of a forepaw, reproducible impedance decreases of 4.5 +/- 2.7% and 2.7 +/- 2.4% (mean +/- SD) respectively occurred in appropriate cortical areas, with a time course similar to the period of stimulation. They were accompanied by adjacent smaller impedance increases. The decreases are probably due to increased blood flow and temperature; the cause of the adjacent increases may be a shadowing artefact of the reconstruction algorithm or due to physiological shrinkage of the extracellular space. This demonstrated, for the first time, that such small changes may be imaged under optimal conditions. These results are encouraging to the prospect that EIT may eventually be suitable for imaging evoked responses or epilepsy in human subjects.

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Section: Discussionmentioning

confidence: 99%

“…The mean BP increased on stimulation by 15 ± 5 mm Hg. The SEPs were typically 30 µV in amplitude, with latencies of P1 13.8 ± 1.5 and N1 32.8 ± 3.0 ms (n = 5 in three animals, nomenclature as Colin et al (1980)) (see figure 6).…”

Section: Eit Images During Somatosensory Evoked Responsesmentioning

confidence: 99%

Imaging of physiologically evoked responses by electrical impedance tomography with cortical electrodes in the anaesthetized rabbit

1996

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“…Indeed, the human cortex gyri disort the currentflow, making it difficult to choose between the possible orientations of the putative dipoles. The rabbit proved to be a suitable model, its parietal contralateral cortical evoked response after forelimb stimulation ( COLIN et al, 1980) being similar to the postrolandic response in man. Their simpler vertical processing-units (KILLACKEY, 1983) can be compared to the primate cortex's columnar organization.…”

Section: Interchangeability Of Stimulus Intensity and Duration For VImentioning

confidence: 87%

Société Belge De Physiologie Et De Pharmacologie Fondamentales Et Cliniques Belgische Genootschap Voor Fundamentele En Klinische Fysiologie En Farmakologie

1987

Archives Internationales de Physiologie et de Biochimie

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Voltage dependent t,+ and pH-induced hyperpolarization of the basolateral membrane of amphibian proximal tubule in the presence of lidocaine or Ba2+.After complete isolation and artificially perfusion of Necturus kidney with HC0;free Hepes solution, early proximal tubular cells were impaled with conventional microelectrodes to observe the peritubular membrane potential ( V,) during successive short-term peritubular changes of experimental solutions. A pH change from 7.5 to 8.5 induces a significant hyperpolarization of -8.8 & 0.6 mV (SEM) (n = 79).Peritubular K+ concentration steps from 2.5 to 10 mM at pH 7.5 and 8.5 reveal that the apparent transference numbers of potassium (tK+) are linearly related to V, for both pH values. However, since the pH-induced hyperpolarization (pHIH) was not voltage-dependent, other mechanisms besides changes in potassium permeability could contribute to the pHIH. In order to check this possibility the effect of two known potassium blockers, lidocaine and barium, was investigated.Addition of 1 mM lidocaine at pH 7.5 elicited a depolarization of V, of +9.3 f 1.0 mV (n = 30) and a reduction of t,+. Nevertheless pHIH in the presence of lidocaine remained : AV, = -10.0 k 1.2 mV (n = 14). Addition of 2 and 6 mM Ba2+ at pH 7.5, depolarized V, by +24.8 f 2.0 mV (n = 29) and + 28.0 t 1.6 mV (n = 25) whilst pHIH amounted to -8.2 2 0.7 mV (n = 43) and -9.6 f 1.9 mV (n = 8), respectively. t,+ became zero in the presence of BaZ+.Thus, besides the increase in PK+ of the basolateral membrane elicited by an alkaline pH, other mechanisms as well contribute to the generation of pHIH of the basolateral membrane. ( I ) Publication subsidite par le Ministere de I'Education Nationale et de la Culture. Publicatie gesubsidieerd door het Ministerie van Nationale Opvoeding en Cultuur. Archives Internationales de Physiologie et de Biochimie, 1987, 95 (2) Archives of Physiology and Biochemistry Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/26/14 For personal use only. Campus Gasthuisberg, B-3000 Leuven). Reference BIEKMANS, G., VEREECKE, J. & CARMELIET, E. (1985) Arch. int. Physiol. Biochim. 93 (2). P17-Pl8. Archives Internationales de Physiologie et de Biochirnie, 1987, 95 (2) Archives of Physiology and Biochemistry Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/26/14 For personal use only. Experientia 41, 900-905.445-45 1. Archives Internationales de Physioiogie et de Biochimie, 1987, 95 (2) Archives of Physiology and Biochemistry Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/26/14 For personal use only. Archives Internutionales de Physiologie et de Biochimie, 1987, 95 (2) Archives of Physiology and Biochemistry Downloaded from informahealthcare.com by Chinese University of Hong Kong on 12/26/14 For personal use only. SOC. BELGE DE PHYSIOLOGIE ET DE PHARMACOLOGIE, LEUVEN, NOVEMBRE 1986 P5 P. LEKEUX (Laboratoire d'lnvestigation fonctionnelle, Faculti de Mddecine Vdtirinaire, ULg, Rue des Vetdrinaires 45, B-I070 ...

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Discriminant Parameters Representing Cerebral Cortical Function During Anoxic Anoxia Investigations

Waeyenberge

Vermariën

Backer

et al. 1985

Advances in Experimental Medicine and Biology

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Properties of Cortical Somatosensory Evoked Potentials in the Awake Rabbit

Cited by 5 publications

References 13 publications

Imaging of physiologically evoked responses by electrical impedance tomography with cortical electrodes in the anaesthetized rabbit

Imaging of physiologically evoked responses by electrical impedance tomography with cortical electrodes in the anaesthetized rabbit

Société Belge De Physiologie Et De Pharmacologie Fondamentales Et Cliniques Belgische Genootschap Voor Fundamentele En Klinische Fysiologie En Farmakologie

Discriminant Parameters Representing Cerebral Cortical Function During Anoxic Anoxia Investigations

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