The Localization of the Center Dealing With the Tonic Extensor Seizure of Electroshock

Tanaka, Kiyoshi; Mishima, Osamu

doi:10.1254/jjp.3.6

Cited by 21 publications

(5 citation statements)

References 2 publications

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“…MESinduced seizures are immediately tonic, beginning with tonic tlexion followed by extension. According to this line of reasoning, the supramaximal stimulus immediately triggers paroxysmal discharge from all areas of the brain including the system responsible for tonic convulsions, i.e., the brainstem R E That the stimulating current delivered through corneal electrodes can directly activate epileptic discharge in the brainstem is supported by the findings of Tanaka and Mishima (1953) showing that MES can still induce tonic seizures after brain transection at the midbrain and pontine levels. This could occur only if the current activated the area caudal to the transection.…”

Section: Discussionmentioning

confidence: 96%

Effect of Midbrain and Pontine Tegmental Lesions on Audiogenic Seizures in Genetically Epilepsy‐Prone Rats

et al. 1985

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A bilateral mechanical lesion of the midbrain and pontine tegmentum was found to abolish completely the tonic components of sound-induced seizures in genetically epilepsy-prone rats (GEPR) that display tonic-clonic seizures. Correlations between varied lesions placements and effects on maximal audiogenic seizures provided evidence that damage to the nucleus reticularis pontis oralis (RPO) of the midbrain and pontine reticular formation (RF) was responsible for the seizure-attenuating effects. Moreover, electrolytic lesions of the pontine RF involving the RPO nucleus were found to abolish the tonic components of the maximal audiogenic seizure. Additionally, bilateral mechanical lesions involving the RPO nucleus were found to attenuate the clonic components of sound-induced seizures in GEPR that display only running seizures and clonus. These findings are consistent with previous studies showing that pontine tegmental lesions attenuate the tonic components of maximal electroshock- and pentylenetetrazol-induced seizures, and lend further support to the hypothesis that all generalized tonic seizures share a common neural substrate. The role of the brainstem RF in tonic versus clonic convulsions is discussed in light of the present findings.

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Section: Discussionmentioning

confidence: 96%

Effect of Midbrain and Pontine Tegmental Lesions on Audiogenic Seizures in Genetically Epilepsy‐Prone Rats

et al. 1985

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“…Available stimulation and lesion data suggest that tonic motor seizures probably originate in pre-motor circuits of the brainstem (Tanaka and Mishima, 1953;Kreindler et al, 1958;Browning et al, 1981;Burnham, 1987) andcerebellum (Raines and Anderson, 1976). Activity generated within these circuits is relayed via reticulospinal projections (Van der Kooy, 1987) to motor neuron pools in the spinal cord which express tonic limb extension (Jobe, 1987).…”

Section: Mechanisms Suppressing Tonic Hindlimb Extensionmentioning

confidence: 99%

Regional Distribution of the Anticonvulsant and Behavioural Effects of Muscimol Injected into the Substantia Nigra of Rats

Shehab

Simkins

Dean

et al. 1996

Eur J of Neuroscience

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Previous anatomical investigations have reported a direct projection from substantia nigra pars lateralis to the dorsal midbrain anticonvulsant zone. The present study tested the hypothesis that the anticonvulsant properties of nigral inhibition previously attributed to substantia nigra pars reticulata were, in fact, due to the suppression of neural activity in the adjacent pars lateralis. Using the electroshock model of epilepsy, a systematic map of the anticonvulsant effects of bilateral injections of muscimol (60 ng/0.5 mu l per side) into different parts of substantia nigra was constructed. Electroshock (1 s of 40 mA 50 Hz AC) was administered via ear-clip electrodes 5 or 60 min following injections of muscimol, or 60 min after control injections of saline. To provide insight into the functional mechanisms whereby nigral inhibition might suppress tonic seizures the behavioural effects elicited by muscimol were also noted. No evidence supporting the experimental prediction was found. The most sensitive region of substantia nigra for suppressing tonic hindlimb extension was caudal pars reticulata. These data indicate a serious mismatch between the results of microinjection mapping studies and underlying patterns of anatomical connectivity. The behavioural reaction most closely associated with tonic seizure suppression was stereotyped locomotion; both were obtained maximally from caudal pars reticulata. Rostral substantia nigra was associated more with oral stereotypy, while a raised head position was observed at lateral injection sites and a lowered positioning of the head at medial locations. These data suggest that the rat substantia nigra may contain a functional organization based on a form of somatomotor topography. This organization may influence which part of the substantia nigra is most effective in suppressing seizures expressed by different muscle groups of the body.

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“…It should be noted that early studies carried out by Tanaka and Mishima (1953) employed complete brain transections in an attempt to identify the "center" responsible for the tonic extensor component of maximal electroshock seizures in rabbits. Although subsequent studies in mice (Tanaka and Kawasaki, 1957) caused them to abandon their concept of a "tonic center," both studies showed that transections at the pontomedullary border completely abolished tonic extension, while transections rostra1 to the pons had no effect.…”

Section: Discussionmentioning

confidence: 99%

Effect of Midbrain and Pontine Tegmental Lesions on the Maximal Electroshock Seizure Pattern in Rats

et al. 1981

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A bilaterally induced mechanical lesion of the midbrain was highly effective in abolishing the hindlimb extensor (HLE) component of the maximal electroshock seizures (MES) in rats. Although these lesions produced damage to a variety of midbrain structures, correlations between different lesion placements and effects in the MES test provided evidence that damage to superior cerebellar peduncle (PCS) and/or reticular formation (RF) was responsible for inhibition of hindlimb extension. Moreover, discretely placed electrolytic lesions disrupting either the PCS or the RF were found to abolish the hindlimb extensor component of the MES test. These findings are consistent with the work of other investigators showing that total cerebellectomy abolishes the HLE component of MES and suggest that activity in the cerebellum and the midbrain reticular formation plays a major role in regulating the tonic phase of electroshock induced seizures.

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The Localization of the Center Dealing With the Tonic Extensor Seizure of Electroshock

Cited by 21 publications

References 2 publications

Effect of Midbrain and Pontine Tegmental Lesions on Audiogenic Seizures in Genetically Epilepsy‐Prone Rats

Effect of Midbrain and Pontine Tegmental Lesions on Audiogenic Seizures in Genetically Epilepsy‐Prone Rats

Regional Distribution of the Anticonvulsant and Behavioural Effects of Muscimol Injected into the Substantia Nigra of Rats

Effect of Midbrain and Pontine Tegmental Lesions on the Maximal Electroshock Seizure Pattern in Rats

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