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R Porter

Publications and source records attributed to R Porter.

At least 163 records · Page 9Linked to original sources
PubMed1983

Plasticity of motor behavior in monkeys with crossed forelimb nerves.

Monkeys in which nerves innervating the flexor muscles of the forearm and hand (the ulnar or the median nerve) had been surgically cross-united with the nerve innervating the extensor muscles (the radial nerve), and vice versa, showed excellent (ulnar-radial crosses) to moderate (median-radial crosses) control of movement performance after regeneration. Antagonistic movement responses were seen occasionally, but these were corrected almost immediately. Stimulation of the crossed nerves showed that they had innervated the antagonistic muscle groups. The results reveal the capacity of the primate central nervous system to adapt to gross disturbances imposed on the execution of movements by changes in peripheral innervation.

Animals↗
PubMed1983

Supplementary motor area and premotor area of monkey cerebral cortex: functional organization and activities of single neurons during performance of a learned movement.

In the conscious, behaving monkey trained to perform a motor task either self-paced or involving light cues, a restricted area responsive during performance of the task can be found in cytoarchitectonic area 6 at the level of the concavity of the arcuate sulcus. Within this area, different groups of neurons can be identified in relation to experimental variables. First a group related in its activity to specific aspects of movement performance. Second, a group associated with movements and visual events, and third, a group modulated in its activity throughout the execution of the task. A few neurons are related to visual cues only. In the first group, a subpopulation exists of neurons active with movements of either extremity; this group resembles similar neurons in SMA. Such neurons can be associated with proximal or distal movements suggesting PM is not an area involved mainly in the maintenance of body posture. The PM may function as a visuomotor integration center as evidenced by the large number of neurons influenced by visual aspects of the tasks. This is also suggested by findings in lesion studies in monkeys and man. Studies in conscious monkeys and man point to a role for PM in motor learning, when a new motor program is established or a previously learned one modified.

Afferent Pathways↗
PubMed1982

Shutting people up.

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History, Ancient↗
PubMed1982

[Not Available].

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History, Modern 1601-↗
PubMed1980

Lafora disease: diagnosis by liver biopsy.

We have studied four patients who had a clinical course compatible with Lafora disease. The diagnosis was confirmed in one by the presence of Lafora bodies in central nervous system neurons at autopsy and was supported in another by findings in the cerebral biopsy of a sibling. Our patients had no clinically apparent liver disease, but liver specimens in each instance showed a distinctive histological abnormality, with hepatocytes containing inclusions having a ground-glass appearance. The liver biopsy findings appear to be relatively specific for this disorder and can easily be differentiated from those in other liver diseases.

Adolescent↗
PubMed1980

What is area 3a?

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Afferent Pathways↗
PubMed1980

The monkey globus pallidus: neuronal discharge properties in relation to movement.

1. Recordings were made of the natural discharges of 388 pallidal neurones in awake, free-to-move monkeys in order to describe the discharge properties of such neurones in relation to normal movement performance. 2. Of the 388 neurones, 156 discharged only in association with one direction of movement of the forelimb about a specific joint. If that movement was not taking place the neurone would not discharge. 3. All joints and directions of movement for the upper limb were represented by clusters of cells within the pallidal population. 4. Twenty-nine per cent of neurones co-varied with movement of both contralateral and ipsilateral limb for the same direction of movement about a given joint; distal movements were represented with similar frequency to proximal movements in this group. 5. Afferent information provided by natural stimulation of peripheral receptors did not directly influence either the discharging or non-discharging pallidal neurones. 6. Movement related neurones were regionally organized and were found in the posterior part of the pallidum.

Action Potentials↗