Effects of Medullary Pyramidotomy in the Monkey: Ii. Abnormalities of Spindle Afferent Responses

Gilman, Sid; Marco, Luis A.; Ebel, Harvey C.

doi:10.1093/brain/94.3.515

Cited by 33 publications

(10 citation statements)

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“…The long-term observations on the status of reflexes in these animals support the earlier findings of Gilman et a1 [14], Tower [29], and Goldberger [151 that the pyramidal animal remains paretic, hypotonic, and normoreflexic. This study affirms the importance of the facilitation provided by the pyramidal tract on alpha motor neurons concerned with the strength and discreteness of distal extremity movement [ 5 , 18, 271.…”

Section: Discussionsupporting

confidence: 85%

A Behavioral analysis of complete unilateral section of the pyramidal tract at the medullary level in macaca mulatta

Schwartzman

1978

Annals of Neurology

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Ten Macaca mulatta monkeys were operantly conditioned to perform three motor paradigms designed to evaluate single and combination finger movements. Eight of these monkeys were retested after left medullary pyramidotomy; 2 monkeys underwent left medullary pyramidotomy prior to conditioning. All animals were tested for three years after operation. Monkeys with a completely sectioned medullary pyramid could, with time, perform difficult motor paradigms that required: (1) both individual and combination finger movements; (2) proximal upper extremity motor control; (3) thumb and index finger pincer grasp; and (4) the ability to preprogram and then execute a precision hand movement. The greater the extent of pyramidal tract destruction, the longer the time necessary for recovery of both discrete finger movement and pincer grasp, the greater the effort needed to attain recovery of hand function, and the weaker the affected musculature. The 2 animals in which pyramidotomy of at least 70% of the tract preceded efforts at operant conditioning learned and performed difficult motor paradigms. In all animals, neurological examination revealed that the most enduring and functionally most important deficit that interferes with hand function following pyramidotomy is loss of contactual hand orienting responses and failure of reflex sensorimotor adjustments.

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Section: Discussionsupporting

confidence: 85%

A Behavioral analysis of complete unilateral section of the pyramidal tract at the medullary level in macaca mulatta

Schwartzman

1978

Annals of Neurology

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“…8 Previous studies have reported an opposite effect of the cerebellum on the motor cortex; electrical9 and magnetic'0 cerebellar stimulation produced a phasic inhibition of the motor cortex. Tonic facilitation, suggested by our study, and phasic inhibition produced by cerebellar stimulation are probably due to a different functional state of cerebellar neuronal elements.…”

Section: Discussionmentioning

confidence: 97%

Excitability of the motor cortex to magnetic stimulation in patients with cerebellar lesions.

Lazzaro

Restuccia

Molinari

et al. 1994

Journal of Neurology, Neurosurgery & Psychiatry

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The excitability of the motor cortex to magnetic stimulation was evaluated in seven patients with cerebellar lesions (six patients with a unilateral lesion) and in 20 control subjects. Magnetic motor threshold was defined at rest. In all but one of the patients with a hemicerebellar lesion the threshold was higher in the motor cortex contralateral to the impaired hemicerebellum and the rightl left threshold asymmetry was clearly greater than normal. In the patient with a lesion involving both cerebellar hemispheres the magnetic threshold was above the normal limit on both sides. The latencies of motor responses were normal in all patients. This increase in the magnetic threshold of the motor cortex functionally related to the impaired hemicerebellum suggests the existence of a facilitating tonic action of the cerebellum on central motor circuits that might act at the cortical, or spinal level, or both. (3 Neurol Neurosurg Psychiatry 1994;57: 108-1 10)

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“…4.1.4), the following may be named (see also references above and below): motor cortex and pyramidal tract (Mortimer and Akert 1961;Kato et el. 1964;Gilman et al 1971b), cerebellum (Granit et el. 1955;Gilman and McDonald 1967;Gilman 1968), ventrolateral nucleus of the thalamus (Yanagisawa et al 1963;Gilman et al 1971a), reticular formation (Shimazu et al 1962a,b).…”

Section: Similarities and Differences Between ~-And ~/-Motoneuronesmentioning

confidence: 99%

The mammalian muscle spindle and its central control

Hulliger

1984

Reviews of Physiology, Biochemistry and Pharmacology

242

156

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Effects of Medullary Pyramidotomy in the Monkey: Ii. Abnormalities of Spindle Afferent Responses

Cited by 33 publications

References 0 publications

A Behavioral analysis of complete unilateral section of the pyramidal tract at the medullary level in macaca mulatta

A Behavioral analysis of complete unilateral section of the pyramidal tract at the medullary level in macaca mulatta

Excitability of the motor cortex to magnetic stimulation in patients with cerebellar lesions.

The mammalian muscle spindle and its central control

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