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S Finger

Publications and source records attributed to S Finger.

At least 73 records · Page 4Linked to original sources
PubMed1978

Postweaning environmental stimulation and somesthetic performance in rats sustaining cortical lesions at maturity.

Rats were enucleated at 28 days of age and were assigned to complex or relatively barren tactile environments for the duration of the experiment. Approximately half of the animals in each group received large, bilateral lesions of the somatosensory cortex when they were 60 days of age, and the remainder underwent sham operations. Twenty days later all groups were tested for the ability to master a series of tactile discriminations. Statistical tests revealed a highly significant lesion effect, but no environment or lesion x environment interaction effects. These sensory discriminative findings stand in contrast to some earlier reports which have shown that environmental complexity provided prior to or following other forebrain lesions can minimize error scores on simple learning tasks.

Animals↗
PubMed1976

Effects of serial lesions of somatosensory cortex and further neodecortication on retention of a rough-smooth discrimination in rats.

Five groups of rats with bilateral lesions of the somatosensory cortex and one of animals sustained only sham operations were tested for retention of a rough-smooth discrimination. Two of the lesion groups had sequential unilateral ablations, in one case with interoperative testing, and three groups had one-stage bilateral lesions. The two groups of animals with serial lesions did not differ from each other or from sham operates in relearning the task. RAts with one-stage lesions and preoperative overtraining also performed well, but the other one-stage groups showed deficits relative to control and serial lesion groups. In the second experiment the sham operated rats from Experiment 1 experiences lesions anterior and posterior to the somatosensory zones. These lesions did not affect retention. Somatosensory cortex then was ablated in one operation and severe performance decrements were seen. Removal of additional neocortex in a sample of animals that had relearned the discrimination after one-stage somatosensory cortex lesions (Exp. 1) also affected retention. In contrast, retention was not impaired on some of the measures in those animals that originally had two-stage ablations. The findings from these two experiments show that some ablation effects can be circumvented with overtraining or serial lesion techniques. The data also indicate that non-somatosensory cortex may play a role in recovery after somatic cortex lesions, but that the substrates underlying recovery might not be the same after one-stage and two-stage ablations.

Animals↗
PubMed1975

Effects of serial lesions of somatosensory cortex and further neodecortication on tactile retention in rats.

Four groups of rats with bilateral lesions of somatosensory cortex and one of animals sustaining only sham operations were tested for retention of a difficult tactile discrimination. Two of the lesion groups had serial ablations, in one case with interoperative testing, and two had one-stage lesions. Bilateral ablations of somatosensory cortex severely retarded retention in all lesion groups relative to the control group and serial and one-stage groups did not differ from each other. The sham operated rats then experienced lesions of cortex anterior and posterior to the somatosensory areas. These lesions only marginally affected retention. Somatosensory cortex then was ablated and severe performance decrements were seen. Removal of additional neocortex in animals that previously had relearned the discrimination after somatosensory cortex lesions also resulted in very poor retention. These data demonstrate the importance of the somatosensory cortex in mediating tactile discriminations and suggest that non-somatosensory cortex may play a role in recovery after somatosensory cortical lesions.

Animals↗
PubMed1975

Long-term deficits after somatosensory cortical lesions in rats.

Rats having either sham operations or one-stage bilateral lesions of the two somatosensory areas of the cortex were tested for acquisition of five tactile discriminations after postoperative recovery intervals of 14, 35, 180, 365 or 730 days. The group with lesions performed worse than its time-matched control group in every instance, and there was no evidence for recovery of function with the longer postoperative recovery periods. These results suggest that time per se is not a significant determinant of restitution after somatosensory cortical ablations.

Animals↗
PubMed1975

Cerebral units activated by tactile stimuli via a ventral spinal pathway in monkeys.

Extracellular microelectrode recordings were made in the forelimb and/or hindlimb areas of the cerebral post-central gyri of 7 monkeys before and/or after acute dorsal hemisections of the cervical or low thoracic spinal cord. The animals were anaesthetized with either pentobarbitone sodium or chloralose. Among the units which were encountered after the lesions were 114 which could be influenced from the periphery. 38 units discharged to light tactile stimulation of small receptive fields and had a topographical organization like that observed in the intact animal. The remaining 76 units could be activated by peripheral electrical stimulation and/or by tapping, squeezing or light pinching. No units were found which specifically were activated by noxious stimuli. The two groups of cortical units responded with latencies only slightly longer than those obtained in the intact preparation. In the light of previous findings these electrophysiological data suggest that, unlike carnivora, primates may possess the ventral spinal somatosensory pathway traditionally postulated on the basis of neurological material.

Animals↗
PubMed1974

Temperature sensitivity of the paw of the cat: a behavioural study.

1. Cats were trained to respond to differences between the temperatures of the floors of two corridors of a modified T-maze for a food reward.2. The cats were able to respond to differences between warm temperatures or differences between cool temperatures in the range of 1 degrees C.3. Both warm and cool discriminations were mediated by receptors located in or near the footpads.4. The paw of the cat thus appears to be more sensitive to temperature changes than was believed previously, and its temperature sensitivity may be comparable to that of the hand of the primate.

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