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Biomedical subjects

A Grabowska

Publications and source records attributed to A Grabowska.

At least 55 records · Page 3Linked to original sources
PubMed1992

Instability of hemispheric asymmetry in dyslexic children.

The study tested the hypothesis of abnormal brain asymmetry in dyslexic children. Two dyslexic groups classified as "phonetic disorder" and "language disorder" and a control group participated in two experiments. In both experiments was employed a dichotic listening procedure consisting in recalling pairs of words presented simultaneously to two ears. In Experiment I the children were to recognize four words presented at a level of loudness typical for natural speech. In Experiment II only two words were used in each trial but they were presented at a low intensity level. The recognition scores for stimuli presented to the left and right ears were compared. In Experiment I all groups of children showed a typical right ear/left hemisphere superiority, i.e. their recognition scores were higher for the right than for the left ear. Dyslexics, however, performed significantly less well. In Experiment II the control children and those from "phonetic disorder" group again performed better when words were presented to their right ears. Unlike those two groups, the children from "language disorder group" showed the right hemisphere superiority, i.e. they performed better in the left ear presentation condition. The results do not support the hypothesis that dyslexic children have abnormal lateralization of verbal functions. They suggest that the pattern of hemispheric asymmetry in dyslexics is less stable and depends both on the kind of dyslexia and on task variation.

Brain↗
PubMed1990

Human trophoblast cells in culture express an unusual major histocompatibility complex class I-like antigen.

We present evidence that the trophoblast cells obtained from first trimester placentae by a culture method developed in our laboratory express a class I-like HLA antigen that is only sparsely distributed on the cell surface, lacks classical polymorphic determinants, and consists of heavy chains of lower molecular weight than those of classical HLA in association with beta 2-microglobulin (beta 2M). The latter two features are in general agreement with a previous report describing the nature of the HLA molecule on trophoblast disaggregated from term amniochorion. These cultured trophoblast cells could be useful for molecular studies of the unusual class I antigen, as well as for other in vitro experiments designed to mimic the in vivo local trophoblast-uterine interactions.

Antibodies, Monoclonal↗
PubMed1989

Impaired grating discrimination following right hemisphere damage.

We investigated the effect of unilateral brain lesions on visual discrimination of low-, middle- and high-frequency gratings. The performance of patients with right hemisphere lesions was significantly impaired compared with that of both controls and patients with left hemisphere lesions. This impairment was largely limited to patients with right posterior hemispheric lesions and was present with all spatial frequencies. These findings run counter to the hypothesis that high and low spatial frequencies are preferentially processed by different hemispheres.

Adult↗
PubMed1988

Left hemisphere superiority for visuospatial functions in left-handers.

Male and female left- and right-handers have been tested with a divided visual field technique on a visuospatial (discrimination of angle width) and on a verbal task (vowel-consonant discrimination) using either a choice or a Go-No-go manual reaction time paradigm. Right-handers showed the expected pattern of hemispheric asymmetries with an advantage of the right hemisphere in the visuospatial task and an advantage of the left hemisphere in the verbal task. Such effects were statistically reliable only in male subjects. Left-handers, on the contrary, showed a different pattern of asymmetries. In the visuospatial task there was an overall superiority of the left hemisphere, while no hemispheric asymmetry was found in the verbal task.

Adult↗
PubMed1988

[Incidence of simple goiter among the population of the Gołdap community].

The possibility of the occurrence of goiter endemia++ among the inhabitants of Gołdap community in the Suwałki voivodeship has been investigated. The investigations embraced 2488 persons, i.e. 21% of the population of the studied community. The occurrence of goiter was revealed in 38% of the investigated persons, and this observation lead to the conclusion that goiter is endemic among the population of the Gołdap community. Such features as high incidence of thyroid enlargement of low degree (OB and I), higher incidence of goiter in women than in men, absence of cases with hypothyroidism, and low incidence of nodular goiter, characterize the observed endemia++ as mild.

Adult↗
PubMed1985

Hemispheric asymmetry in face perception tasks of different cognitive requirement.

Three laterality experiments using tasks of different cognitive requirement were performed in order to determine the stage at which hemispheric differences in face perception arise. All experiments employed the same set of faces and a vocal reaction time paradigm. In experiment 1, subjects were required to discriminate male from female faces and no hemispheric asymmetries were found. In experiment 2, subjects were required to decide whether or not faces were of famous or unknown people and a right hemisphere advantage was found. Finally, in experiment 3 subjects were required to verbally identify the famous faces and no hemispheric differences were found. The results suggest that a right hemisphere superiority exists for the comparison of stimulus faces with an internal representation. Contrary to expectation, face naming does not result in a selective left hemisphere involvement.

Adult↗
PubMed1983

Lateral differences in the detection of stereoscopic depth.

The experiment investigated the hemifield differences in stereoscopic depth perception. Random dot stereograms (Julesz figures) producing the experience of a square appearing in front or behind the fixation plane were used as stimuli. The patterns in depth were exposed either in the left or in the right side of the stereograms for 30 msec. Three different magnitudes of depth were used. The results showed a higher amount of correct detections of depth in the left visual field than in the right visual field. The effects of direction and magnitude of depth were also significant. The hypothesis referring the observed results to the right hemisphere superiority in stereoscopic depth perception is discussed.

Adolescent↗
PubMed1980

Evoked response correlates of letter recognition.

The positive late wave of the average evoked responses induced by tachistoscopic presentation of single letters had a higher amplitude when the letters were correctly recognized than when they were not. The results suggest that the late positive component of VER is a correlate of complex cognitive processes engaged in object’s identification.

Cognition↗
PubMed1979

Interactions between two spatially separated letters presented in succession.

The interactions between two letters presented in succession to neighboring regions of retina were investigated. The interstimulus intervals were: 0, 20, 60, 250 ms, 2.5 s. In control trials single letters were presented in two positions corresponding to the positions of letters in pairs. The recognition of a letter presented as the first element of pairs with either simultaneous presentation or with 250 ms delay of the second element was significantly better than the recognition of single letters. On the contrary, the interstimulus interval 20 and 60 ms yielded an increase of errors made in the recognition of the first letter. The results are interpreted in terms of inhibitory interactions between transient and sustained channels, and in terms of hypothesized excitatory connections between the cortical cells responding to visual elements forming more complex patterns.

Female↗
PubMed1979

Search for structures involved in integration of letters in pairs.

Two experiments aimed at finding, at what stage of perceptual processing the positive interactions between letters, observed in some previous studies, are established. Single letters and pairs of letters were exposed. The task of the subjects was to recognize letters. In Experiment I bright letters on a black background were used instead of black letters on bright background used in previous experiments. Such change of brightness within the stimuli did not influence the character of interactions between letters. This suggests that the positive interactions are connected with higher level of visual system. In Experiment II patients with damage of various areas of the brain cortex were tested. The facilitation between two letters did not occur in patients with prestriate lesions, although it can be observed in patients with different localization of lesions. This suggests that prestriate cortex is involved in positive interactions between letters.

Cerebral Cortex↗