Abstract The aim of the present study is to investigate the neural bases of the visual spatial attention during the execution of cognitive and motor tasks. Twenty volunteers took part to the experiment. They were all right-handed, healthy and without previous neurologic disorder, with normal or glasses corrected vision; their age ranged between 20 and 35 years; 10 of them were male, 10 female. In this study 2 tasks of the original ANT paradigm version, were used (Fan et al., 2002): the task with the Central Cue and the one with Local Cue; differently from the previous studies, we have added 2 more tasks, the first consists in the execution of a Cognitive task during the performing of the Local Task, this task is called Local Cognitive Cue; the other one consists in a modified version of the ANT's paradigm Local Cue, named Local Motor Cue. The tasks were 4 in total and the subjects should execute the same task as the one of the ANT's paradigm original version, that is they had to discriminate the direction of a central arrow, that was inserted in a series of arrows, by pressing a key; the target could be sorrounded by flankers pointed in the same or in the opposite direction. In the Central Cue task, the arrows were advanced by a non informative cue, in the Local Cue task, the cue was local or informative; in the Local Cognitive Cue task, the subjects should execute the same task as the one of the Local Cue task while doing a cognitive task (counting); finally in the Local Motor task, targets could differ from their direction, their congruence to the flankers and also from their tipe of arrow, so that the subjects had to use 4 fingers instead of 2, to express their decision. Both behavioural (reaction times, number of errors and omissions) and electrophysiological data showed a difference between the tasks; only the behavioural data showed a significative difference between the Congruent and the Incongruent conditions, while the electrophysiological data showed this difference. As for behavioural data, subjects had more difficulties (total errors number and longer response time) in the Local Motor Cue task; while the larger number of omissions was found in the Local Cognitive Cue task. P300 ERP component was found to have a greater maximum amplitude and longer latency for the Motor Cue tasks (6.736 ?V; 456 ms), while in the Central, Local and Local Cognitive Cue tasks, the latency of the component was similar (respectively 398, 399 and 401 ms), but presented a minor amplitude for the Cognitive task (4.509 ?V) related to the other tasks (CC 6.623 ?V; LC 6.196 ?V). SwLORETA revealed different P300 generators in the 4 tasks, in the interval of 315 and 630 ms, with a major amplitude for the Motor Task and with a parietal distribution. The outcomes of statistical analysis on ERPs data and of their intra-cortical generators, found by means of swLORETA source reconstruction technique, support the results of studies suggesting that the resolution of the conflict tasks implies the functioning of the frontal areas, in particular of the lateral prefrontal cortex and of the anterior cingular cortex for the hardest tasks.
Discriminating between cognitive and motor processes involved in visual attention tasks.
Zani A
2010
Abstract
Abstract The aim of the present study is to investigate the neural bases of the visual spatial attention during the execution of cognitive and motor tasks. Twenty volunteers took part to the experiment. They were all right-handed, healthy and without previous neurologic disorder, with normal or glasses corrected vision; their age ranged between 20 and 35 years; 10 of them were male, 10 female. In this study 2 tasks of the original ANT paradigm version, were used (Fan et al., 2002): the task with the Central Cue and the one with Local Cue; differently from the previous studies, we have added 2 more tasks, the first consists in the execution of a Cognitive task during the performing of the Local Task, this task is called Local Cognitive Cue; the other one consists in a modified version of the ANT's paradigm Local Cue, named Local Motor Cue. The tasks were 4 in total and the subjects should execute the same task as the one of the ANT's paradigm original version, that is they had to discriminate the direction of a central arrow, that was inserted in a series of arrows, by pressing a key; the target could be sorrounded by flankers pointed in the same or in the opposite direction. In the Central Cue task, the arrows were advanced by a non informative cue, in the Local Cue task, the cue was local or informative; in the Local Cognitive Cue task, the subjects should execute the same task as the one of the Local Cue task while doing a cognitive task (counting); finally in the Local Motor task, targets could differ from their direction, their congruence to the flankers and also from their tipe of arrow, so that the subjects had to use 4 fingers instead of 2, to express their decision. Both behavioural (reaction times, number of errors and omissions) and electrophysiological data showed a difference between the tasks; only the behavioural data showed a significative difference between the Congruent and the Incongruent conditions, while the electrophysiological data showed this difference. As for behavioural data, subjects had more difficulties (total errors number and longer response time) in the Local Motor Cue task; while the larger number of omissions was found in the Local Cognitive Cue task. P300 ERP component was found to have a greater maximum amplitude and longer latency for the Motor Cue tasks (6.736 ?V; 456 ms), while in the Central, Local and Local Cognitive Cue tasks, the latency of the component was similar (respectively 398, 399 and 401 ms), but presented a minor amplitude for the Cognitive task (4.509 ?V) related to the other tasks (CC 6.623 ?V; LC 6.196 ?V). SwLORETA revealed different P300 generators in the 4 tasks, in the interval of 315 and 630 ms, with a major amplitude for the Motor Task and with a parietal distribution. The outcomes of statistical analysis on ERPs data and of their intra-cortical generators, found by means of swLORETA source reconstruction technique, support the results of studies suggesting that the resolution of the conflict tasks implies the functioning of the frontal areas, in particular of the lateral prefrontal cortex and of the anterior cingular cortex for the hardest tasks.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
