Biomedical subjects

Tomaso Vecchi

Publications and source records attributed to Tomaso Vecchi.

7 recordsLinked to original sources

PubMed2006

Handedness effects on interhemispheric transfer time: a TMS study.

The crossed-uncrossed difference (CUD) estimates the interhemispheric transfer time (ITT) through the corpus callosum. Previous research has shown that transcranial magnetic stimulation (TMS) to the occipital cortex determines an increased CUD during cognitive tasks. The aim of the present study was to investigate whether TMS stimulation applied at a motor stage can interfere with the ITT, comparing the performance of left- and right-handed people. Results showed a significant TMS effect, i.e. increasing reaction times were reported when stimulation was delivered on the left primary motor area. Effects were more evident when information was primarily perceived through the dominant hemisphere. Both left and right stimulations increased CUD times in right-handed subjects; however, left-handed subjects showed significant effects associated with left stimulation only. Furthermore, in both groups, TMS produced larger effects in the crossed than in the uncrossed condition. TMS stimulation increased reaction times, thus supporting the idea that the interhemispheric transfer of visuo-motor information occurs at a motor processing stage. The dominant hemisphere seems to play a major role within this process: our data indicates that left- and right-handed people have different ITT latencies associated with the transfer of information to the contralateral hemisphere.

Adult↗

PubMed2006

Why Cyclops could not compete with Ulysses: monocular vision and mental images.

The present research demonstrates that the limitations of congenitally blind people in tasks requiring the processing of mental images are specifically related to the absence of binocular vision and not to the absence of vision per se. We contrasted three different groups of participants: sighted; visually impaired, with reduced binocular vision; monocular, with a normal visual acuity although in one eye only. Visually impaired participants (i.e. blurred vision) show a pattern of performance comparable to that of the sighted. In contrast, monocular participants show a similar pattern of performance to congenitally blind individuals despite being able to see perfectly well. These results shed new light on the relationship between perception and imagery and on the characteristics of sequential and simultaneous processes in the human brain.

Adult↗

PubMed2006

Gender differences in memory for object and word locations.

It has been hypothesized that gender differences in visuo-spatial working memory (VSWM) are larger in tasks requiring active elaboration of the material. In the present study we explored this issue by using an object relocation task, with both verbal and visual stimuli. The involvement of active processes was manipulated through the type of transformation required on the stimulus and through the introduction of different kinds of interference. In the three experiments reported, participants were shown either words or cartoon object icons in different locations and had to relocate them in either the same format or in the opposite one (object icons could be transformed into words and vice versa). Males outperformed females in the most demanding conditions, in which object icons and words were presented together in the encoding phase, and both had to be transformed in the recall phase; or when more demanding interferences were used. Our data suggest that the retention strategy was similar for the two groups and that the gender effect is related to a selective female difficulty associated with the increase in active VSWM processing. These findings further support the hypothesized distinction between the passive and active components of VSWM and illustrate the role that this distinction might play in accounting for individual differences.

Adult↗

PubMed2004

Spatial memory and integration processes in congenital blindness.

The paper tests the hypothesis that difficulties met by the blind in spatial processing are due to the simultaneous treatment of independent spatial representations. Results showed that lack of vision does not impede the ability to process and transform mental images; however, blind people are significantly poorer in the recall of more than a single spatial pattern at a time than in the recall of the corresponding material integrated into a single pattern. It is concluded that the simultaneous maintenance of different spatial information is affected by congenital blindness, while cognitive processes that may involve sequential manipulation are not.

Adolescent↗

PubMed2003

Modality-specific effects in inhibitory mechanisms: the interaction of peripheral and central components in working memory.

Working memory is a complex system assumed to encompass both storage and processing components. At the same time, several authors have suggested the existence of separate peripheral modality-specific subsystems, in particular a verbal and a visuo-spatial mechanism. In the present research, we explored the hypothesis that modality-specific mechanisms may also operate in the central processing component. Inhibitory control has traditionally been considered as a typical function of the central executive, devoted to selecting, processing, and eliminating irrelevant information. We designed verbal and visuo-spatial tasks involving similar procedures and comparable levels of inhibitory control. Results indicate that accuracy profiles are similar in the two conditions; however, the patterns of data measuring inhibitory control, i.e., percentage of intrusion errors, are opposite in the case of verbal (intrusions decreased in more complex trials) and visuo-spatial (intrusions increased in more complex trials) material. These data are consistent with theoretical models of working memory suggesting that modality-specific effects emerge even in central processes and that both material-dependent and process-dependent features must be considered in working memory tasks.

Adult↗

PubMed2002

A jigsaw-puzzle imagery task for assessing active visuospatial processes in old and young people.

Recent studies have suggested a theoretical distinction between active elaboration and passive storage in visuospatial working memory, but research with older adults has failed to demonstrate a differential preservation of these two abilities. The results are controversial, and the investigation of the active component has been inhibited by the absence of any appropriate experimental procedures. A new task was developed involving the mental reconstruction of pictures of objects from fragmented pieces, and this provides a useful procedure for exploring active visuospatial processing. Significant differences in terms of both correctness and response latency were obtained between young and older adults and between younger old and older old adults. Performance also varied with visual complexity, mental rotation, and processing load. It is concluded that this ecologically relevant procedure constitutes a very powerful, sensitive, and reliable tool for identifying individual differences in visuospatial working memory.

Adult↗

PubMedDate not supplied

Aging and everyday memory: the beneficial effect of memory training.

The authors investigated elderly people's ability to benefit from specific memory training. Empirical evidence of cognitive aging shows a deterioration in working memory ability but also suggests that elderly people maintain the ability to acquire new information and strategies. The aim of the present study was to investigate the effects of two different mnemonic strategies (Loci mnemonic vs. Strategic training) in young and older adults and to evaluate the ability of the older groups to improve performance. Participants received extensive practice in the use of a specific strategy. Three groups of participants (20 adult, 20 younger elderly, and 20 older elderly) were tested in the laboratory, as well as in ecological conditions using a battery of cognitive tests. Questionnaires were also administrated to explore cognitive, metacognitive and emotive motivational aspects of working memory performance. The results show the efficacy of both trainings in improving performances in different tasks, particularly the ecological. The elderly benefit from strategies as much as younger people; nevertheless, the memory performances of the latter are higher. Differences between the two trainings are found only in the task evaluating ability to re-use learnt strategies in other unfamiliar situations. Improvement in performance was more pronounced for the strategic training.

Adult↗