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Biomedical subjects

G Rizzolatti

Publications and source records attributed to G Rizzolatti.

At least 145 records · Page 8Linked to original sources

Spontaneous activity of neurones of nucleus reticularis thalami in freely moving cats.

1. Fifty-four neurones of the caudal part of the nucleus reticularis thalami (nuc. ret.) were recorded during different phases of sleep and wakefulness in unanaesthetized freely moving cats.2. During wakefulness the activity of the neurones was characterized by a continuous, well-spaced discharge. The mean firing rate was 35.58 +/- 15.06 spikes/sec (average +/- S.D.).3. During sleep with synchronized e.e.g. (S-sleep) the neurones fired in high frequency bursts with long pauses in between. Each burst was formed of 10-15 spikes. Often the bursts were followed by prolonged discharges formed of spikes well spaced one from the other. Bursts followed by prolonged activity were more commonly observed at the beginning of S-sleep and during the S-sleep periods preceding sleep with desynchronized e.e.g., whereas bursts immediately followed by silence were more frequent in the S-sleep periods with e.e.g. delta waves. The long periods of silence between the bursts usually lasted over 200 msec and values greater than 1 sec were frequently found. The mean firing rate of neurones during S-sleep was 19.22 +/- 10.50 spikes/sec.4. During sleep with desynchronized e.e.g. (D-sleep) the activity of the neurones was, as during wakefulness, characterized by a continuous, well spaced, unclustered discharge. The mean firing rate was 40.00 +/- 18.74 spikes/sec. During the rapid eye movements of this phase most units increased the frequency of their discharge, which, nevertheless, maintained the unclustered feature proper to the desynchronized phase of sleep.5. Interspike interval distribution was similar during wakefulness and sleep with desynchronized e.e.g., whereas that for sleep with synchronized e.e.g. was markedly different from those for both the other stages.6. The implications of the striking similarity between the activity of reticularis neurones during wakefulness and sleep with desynchronized e.e.g. are discussed.

Action Potentials↗

Binocularly driven neurons in visual cortex of split-chiasm cats.

In cats with midsagittal section of the optic chiasm, some visual cortex neurons can be driven not only by the ipsilateral eye, through the direct geniculocortical pathways, but also by the contralateral eye, through the opposite visual cortex and corpus callosum. The receptive fields and the response characteristics observed upon stimulation of the contralateral eye are very similar to those observed upon stimulation of the ipsilateral eye; the two monocular receptive fields of a given cell lie in corresponding points of heteronymous halves of the visual field in close contact with the vertical meridian, thus adding in visual space and forming a binocular receptive area which crosses the vertical meridian and extends equally on either side of it.

Animals↗