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Biomedical subjects

G Ettlinger

Publications and source records attributed to G Ettlinger.

At least 19 recordsLinked to original sources
PubMed1992

Impaired visual perceptual categorization in right brain-damaged patients: failure to replicate.

The association of both Perceptual Categorization (PC) and Semantic Categorization (SC) with sensory performance was investigated. 28 RBD, 27 LBD and 21 non-brain-damaged subjects were tested with the PC and SC tasks described by Warrington and Taylor (1978) and with 6 sensory tasks. PC was related to sensory performance in RBD but not in LBD patients. SC was only marginally associated with sensory ability in both lesion groups. RBD and LBD patients differed significantly at neither PC nor at SC. Thus the dissociation between PC and SC, described by Warrington and Taylor (1978) was not replicated. Moreover, PC and SC were significantly correlated in both RBD and LBD patients. This suggests that the serial organization of PC and SC is questionable. It is concluded that the associations we obtained between SC, PC and sensory performance are likely to be functional. The contribution of a cognitive factor ("abstraction") to PC and SC is discussed.

Brain Injuries↗
PubMed1979

Object sorting by chimpanzees and monkeys.

Chimpanzees and two species of monkey were compared on sorting tasks. When the sets of objects differed in multiple ways, most chimpanzees learnt to sort whereas only a few monkeys performed better than chance (and then inconsistently). When the objects within a set differed in one or two respects, so that sorting by one principle entailed "unsorting" by one or more alternative principles, chimpanzees had greater difficulty. Two young animals did rapidly learn to sort by color and size ("unsorting" by size and shape or by color and shape). They did not sort pictorial material and had difficulty in sorting by shape if "unsorting" by both color and size. The sorting task differentiated between the cognitive capacities of chimpanzees and monkeys whereas other tasks did not.

Animals↗
PubMed1978

Further evidence of impaired tactile learning after removals of the second somatic sensory projection cortex (SII) in the monkey.

Four rhesus monkeys with bilateral removals of SII and five unoperated monkeys were trained on tests of tactile equivalence, weight discrimination and generalization, tactile discrimination learning (including concurrent learning and serial reversal) and inter-manual transfer of tactile learning. Lesioned animals were impaired on almost all tactile learning tasks and on inter-manual transfer but not on the test of tactile equivalence nor on the propioceptive tasks. The results are considered in the context of previous studies of somatosensory and parietal cortex.

Animals↗
PubMed1978

The effects of ablations on primary and secondary epileptic discharges in commissure-sectioned rhesus monkeys.

Nine monkeys underwent division of the corpus callosum, anterior commissure, massa intermedia, and posterior commissure. At the same operation, in seven of these animals aluminium hydroxide was applied to the left posterior parietal-prestriate cortex. Monthly EEG recordings were taken from all animals. All seven animals with epileptogenic implants gave evidence of primary abnormal discharges (i.e. from the ipsilateral hemisphere) and secondary (i.e. from the contralateral hemisphere) discharges. The secondary events were of two types: transmitted, i.e. synchronous with primary events; independent, i.e. asynchronous with primary events. After intervals varying from 4 to 22 months all seven monkeys underwent wide ablation of the posterior parietal cortex: on the left in four animals, on the right in three animals. EEG recordings were taken for a further 6 months. All recordings were quantitatively analysed, the number of primary, transmitted secondary and independent secondary events being counted separately. This analysis indicated the following: (1) Primary and transmitted secondary discharges ceased after primary ablations but were unaffected by removal of the secondary cortex. (2) Independent secondary discharges persisted after removal of the primary focus but were abolished by secondary ablations. Possible mechanisms for the development of transmitted and independent secondary discharges are considered.

Aluminum Hydroxide↗
PubMed1978

The effects of unilateral or bilateral removals of the second somatosensory cortex (area SII): a profound tactile disorder in monkeys.

Three groups of monkeys were studied; one with bilateral removals of the second somatosensory projection cortex (SII); another with similar unilateral removals; and an unoperated control group. Both lesion groups were significantly impaired on tasks of tactile learning and tactile retention. However, there were no differences between groups on the great majority of tasks of motor learning, nor on spatial alternation in the dark. The animals with unilateral removals were generally impaired whether using the hand contralateral to or ispilateral to the removal.

Animals↗
PubMed1978

Disturbance of cage-finding in the monkey.

Qualitative and quantitative observations were made on two monkeys with unilateral or bilateral removals of areas 5 and 7 of Brodmann. The task was to return to the home cage in the light or in the dark. Both animals were slower in the dark, and also qualitatively abnormal in the light.

Animals↗
PubMed1978

Ability of chimpanzees to respond to symbols of quantity in comparison with that of children and of monkeys.

Four chimpanzees, 4 rhesus monkeys, and 11 children aged 4-9 yr were assessed under comparable conditions for their ability to make use of colors as symbols of quantity. One particular color represented the quantifier "all"; another represented "some"; another represented "one"; a fourth represented "none." These arbitrarily chosen colors retained their individual meanings when the test conditions were varied on three occasions. The ability of the subjects to continue responding appropriately to the colors immediately after a change of test condition was used as the measure of performance. The apes performed like the monkeys, having especial difficulties relative to the children with the most sensitive quantifier "some."

Age Factors↗
PubMed1977

Stimulus- and response-dependent units from the occipital and temporal lobes of the unanaesthetized monkey performing learnt visual tasks.

43% of units recorded from the foveal prestriate cortex, inferotemporal cortex or amygdala of 15 rhesus monkeys performing visual discrimination or serial reversal tasks were responsive to all or some visual stimuli or other aspects of the task. Six units showed activity during movements required for performance of the task. It was not possible to determine whether unit activity could be related to the learnt association of the visual stimuli with reward.

Animals↗
PubMed1977

Spatial disorientation in the monkey.

The incidence of misdirected movements of the hand during tactile discrimination performance in the dark has been tabulated for monkeys with bilateral removals of parieto-prestriate cortex. The observations support the existence of a spatial disorientation (in addition to their inaccuracies of reaching) in these animals.

Animals↗