Biomedical subjects

C Mucignat

Publications and source records attributed to C Mucignat.

5 recordsLinked to original sources

PubMed1992

[Recall of the proper names of persons: effect of age and the modality of access].

Aging is associated with phenomena of slowing down of cognitive processes and impairment of neuropsychological performances. Elderly people also report difficulty in the retrieval of proper names. Verbal fluency (VF) tests are particularly effective for the identification of even slight mental impairments. In this experiment we utilized the usual tests of VF for semantic categories and letters of the alphabet together with three new tests of VF for first names, differing in mode of access. The first mode was free recall, the second mode was semantic (first names beginning with a particular letter), and the third mode was autobiographical (first names of relatives). There were 3 experimental groups: young people with high education level, elderly people with high education level and elderly people with low education level. The aim of our work was to verify whether aging modifies the performance in the VF tests, particularly in the three first name VF tests. No difference was found between the groups of young and elderly people with high education level. The comparison between the two groups of elderly people, with high and low education level, showed that significant differences were present in some but not in all of the VF tests. While the two groups clearly differed in semantically oriented tests, no difference could be detected in the test oriented to episodic memory. This result seems to be inconsistent with the hypothesis that aging affects mainly episodic memory.

Adult↗

PubMed1991

[Orientation of attention in the visual space].

The display was composed of four boxes, horizontally aligned above the fixation point. In Experiment I, each box was cued by a digit shown at fixation. In Experiment II there were only two numeric cues, signalling the inner or the outer boxes, depending on the experimental condition. The subject was instructed to orient attention to the cued box, and to respond to the imperative stimulus as fast as possible, wherever it appeared. By using four time interval (SOAs), we tried to determine the route covered by attention movements. In Experiment I, with the shortest SOA (100 msec), it was shown that attention does not reach the cued box through a direct path. Rather it moves first on the inner boxes, thereafter focusing on the cued location. The same results were obtained in Experiment II, where the cue directed attention to the inner boxes. When the external boxes were cued, however, this trend was not observed.

Adult↗

PubMed1991

[Orientation strategy implicit in spatial attention].

In this experiment, two rows of four boxes, one above and the other below the fixation point, were displayed on a computer monitor. A cognitive numeric cue indicated one of the four external boxes, where the attention was to be directed. Stimuli, however, could occur in any of the eight boxes. The subject was instructed to respond to the imperative stimulus as fast as possible, regardless of its location. Four time intervals between cue and stimulus presentation (SOAs) were employed in order to disclose the route along which attention is moved. With the shortest SOA (100 msec) an indication that attention movements follow the cartesian/orthogonal axes was shown.

Adult↗

PubMed1991

[Effect of age on the orientation of attention: effect of changing the interval between signal and stimulus].

The purpose of the experiment was to examine the effect of aging on spatial attention. One of two possible locations, horizontally arranged, was cued. The subject had to respond to the onset of a visual stimulus, wherever it appeared. The task demand was to orient attention to the stimulated location before producing a response, or to reorient it if the position is not the cued one. Younger and older adults showed the same response pattern, despite the overall slowing down of response presented by the latter.

Adolescent↗

PubMed1985

Influence of sialic contents on the chemiluminescent response of human leucocytes to group B streptococci.

The sialic acid content in reference strains of various Group B streptococci serotypes was studied before and after serial passages in mouse to enhance the virulence. The passages in mouse strongly increased the sialic acid content but the neuraminidase treatment reduced the to comparable values in reference and in virulent strains. The chemiluminescent response of human polymorphonuclear leucocytes to different GBS strains was higher for reference strains and lower for virulent strains. Sialic acid removal by neuraminidase increased the chemiluminescent response in virulent and in reference strains. Negative correlation between sialic acid content and chemiluminescence was demonstrated in strains of the same serotype, before and after passages in mouse and neuraminidase treatment for types Ic, II and III but no correlation was found considering the sialic acid content in strains belonging to different serotypes.

Animals↗