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612 Faster visual processing in the attended space: Electrophysiological evidence
232
Abstracts
/International
Journal
task is a tracking task, which is a typical skill base one. The second task is to recognize the visual information that is indicated by four different media on a computer screen and to respond as soon as possible. The third task is to listen to a conversation and answer a question about the conversation. This task is supposed to be the same as using a cellular phone while driving a car. In this paper we have examined the effect of third task on the first and the second tasks. There was not any effect of the third task on the performance of the tracking task. The time needed to respond after getting the information was affected a little by the third task. The number of overlooking the visual information in the second task significantly increased by the effect of the third task. This point might be one of the causes that result in a car accident.
610 THE EVOKED CARDIAC RESPONSE AS A FUNCTION OF COGNITIVE LOAD IN SUBJECTS DIFFERING ON THE PERFORMANCE OF THE DIVIDED AI-TENTION TASK (DIVA) E. Wronka*, J. Raiser Institute of Psychology, Jagiellonian 13, Krakow, 31-007 Poland
University, ul. Golebia
In the reported experiment we investigated the influence of the stable individual difference variable, dean Reaction Time (RT) prolongation associated with differences in cognitive activity upon the Evoked Cardiac Response (ECRl elicited by innocuous auditory stimuli. The Divided Attention task (DIVA) required subjects to detect the valid stimuli and differentiate them from invalid ones. ECR were measured in two conditions: in IRRELEVANT condition (there was no task involving the stimuli) most often the ECR has a simple decelerative character and in RELEVANT condition (with instruction to silently count the stimuli) the initial HR deceleration is followed by HR acceleration. We found that subjects with smaller prolongation of Reaction Time showed deeper and longer lasting deceleration in IRRELEVANT condition in comparison to the subjects with greater Reation Time prolongation. No significant effect of RT was found in RELEVANT condition. The data are discussed in terms of the intensity of stimulus processing in relation to stable individual differences in divided attention.
611 HIGH DENSITY EVENT RELATED DURING THE MANUAL GAP EFFECT
POTENTIALS
C.M. Gomez I*, S. Millan’, E. Vaqueroi, M.J. Cardoso’ and A. Delinte’ ‘Lab. Psicobiologia, Dto. de Psicologia kxperimental, fat. de Psicologia, Univ. de Sevilla, Sevilla 415005 Spain ‘Lab. de Neurophysiologie, UCL, Belgium
of Psychophysiology300
(1998)
95-271
The gap effect refers to the fact that when a temporal gap between the switching off of a central fixation point and the switching on of a peripheral light, a facilitation in Reaction Time (RT) to peripheral visual targets occurs. Two different kind of hypotheses has been proposed to account for the gap effect when ocular responses are required: Warning, which would include motor preparation, and the disengagement of attention. In order to solve if electrophysiological signs of warning, sensory and motor, occurs, the ERPs during the gap paradigm were obtained. Electroencephalographic (EEG) data were collected from 58 locations on the scalp using tin electrodes mounted in an electrode cap. RTs and event related potentials (ERPs) to Gap and non-Gap conditions were statistically compared. Also, the lateralized readiness potentials (LRPs) were obtained in both conditions and compared. The results show faster responses during the gap condition with respect to non-gap condition. The ERPs showed differences between both conditions, particularly the Pl component was increased in the gap condition. Also, LRPs had a higher amplitude in the gap condition than in the non-gap condition over the motor cortex. These results suggest that the presence of the gap induces sensory and motor priming of the circuits implicated in the visuo-motor task, allowing the acceleration of the manual response.
612 FASTER VISUAL PROCESSING IN THE ATTENDED SPACE: ELECTROPHYSIOLOGICAL EVIDENCE Francesco Di Russo*, Donatella Spinelli Research Center, IRCCS Ospedale S. Lucia, Rome and Department of Psychology, University of Rome “La Sapienza”, 306 Roma, 00179 Italy Visual sustained attention directed to a location without moving the eyes (cover attention) enhanced the perception in that region. The effect of attention was measured on the visual evoked potential (VEP) to a grating continuously displayed in the left visual field. Both steady-state and transient VEPs were recorded. In both conditions a small target (a light changing colour) was presented either in the left or in the right visual field. The task of the subject was to count the number of colour changes, without moving the eyes from the central fixation point. Thus, attention was directed either to the left or to the right visual target while VEPs were recorded from the task-irrelevant grating on the left side. In agreement with previous observations, VEPs amplitude enhancement by attention was present on steady-state and transient experiments. Results go beyond previous findings showing that VEP in the attended condition had shorter latency than VEP in the unattended condition. The difference in latency ranged from 5 to 15 ms. Results are discussed in relation to the hypothesis of attention as a sensory gain control mechanism.
Abstracts
/International
Journal
task is a tracking task, which is a typical skill base one. The second task is to recognize the visual information that is indicated by four different media on a computer screen and to respond as soon as possible. The third task is to listen to a conversation and answer a question about the conversation. This task is supposed to be the same as using a cellular phone while driving a car. In this paper we have examined the effect of third task on the first and the second tasks. There was not any effect of the third task on the performance of the tracking task. The time needed to respond after getting the information was affected a little by the third task. The number of overlooking the visual information in the second task significantly increased by the effect of the third task. This point might be one of the causes that result in a car accident.
610 THE EVOKED CARDIAC RESPONSE AS A FUNCTION OF COGNITIVE LOAD IN SUBJECTS DIFFERING ON THE PERFORMANCE OF THE DIVIDED AI-TENTION TASK (DIVA) E. Wronka*, J. Raiser Institute of Psychology, Jagiellonian 13, Krakow, 31-007 Poland
University, ul. Golebia
In the reported experiment we investigated the influence of the stable individual difference variable, dean Reaction Time (RT) prolongation associated with differences in cognitive activity upon the Evoked Cardiac Response (ECRl elicited by innocuous auditory stimuli. The Divided Attention task (DIVA) required subjects to detect the valid stimuli and differentiate them from invalid ones. ECR were measured in two conditions: in IRRELEVANT condition (there was no task involving the stimuli) most often the ECR has a simple decelerative character and in RELEVANT condition (with instruction to silently count the stimuli) the initial HR deceleration is followed by HR acceleration. We found that subjects with smaller prolongation of Reaction Time showed deeper and longer lasting deceleration in IRRELEVANT condition in comparison to the subjects with greater Reation Time prolongation. No significant effect of RT was found in RELEVANT condition. The data are discussed in terms of the intensity of stimulus processing in relation to stable individual differences in divided attention.
611 HIGH DENSITY EVENT RELATED DURING THE MANUAL GAP EFFECT
POTENTIALS
C.M. Gomez I*, S. Millan’, E. Vaqueroi, M.J. Cardoso’ and A. Delinte’ ‘Lab. Psicobiologia, Dto. de Psicologia kxperimental, fat. de Psicologia, Univ. de Sevilla, Sevilla 415005 Spain ‘Lab. de Neurophysiologie, UCL, Belgium
of Psychophysiology300
(1998)
95-271
The gap effect refers to the fact that when a temporal gap between the switching off of a central fixation point and the switching on of a peripheral light, a facilitation in Reaction Time (RT) to peripheral visual targets occurs. Two different kind of hypotheses has been proposed to account for the gap effect when ocular responses are required: Warning, which would include motor preparation, and the disengagement of attention. In order to solve if electrophysiological signs of warning, sensory and motor, occurs, the ERPs during the gap paradigm were obtained. Electroencephalographic (EEG) data were collected from 58 locations on the scalp using tin electrodes mounted in an electrode cap. RTs and event related potentials (ERPs) to Gap and non-Gap conditions were statistically compared. Also, the lateralized readiness potentials (LRPs) were obtained in both conditions and compared. The results show faster responses during the gap condition with respect to non-gap condition. The ERPs showed differences between both conditions, particularly the Pl component was increased in the gap condition. Also, LRPs had a higher amplitude in the gap condition than in the non-gap condition over the motor cortex. These results suggest that the presence of the gap induces sensory and motor priming of the circuits implicated in the visuo-motor task, allowing the acceleration of the manual response.
612 FASTER VISUAL PROCESSING IN THE ATTENDED SPACE: ELECTROPHYSIOLOGICAL EVIDENCE Francesco Di Russo*, Donatella Spinelli Research Center, IRCCS Ospedale S. Lucia, Rome and Department of Psychology, University of Rome “La Sapienza”, 306 Roma, 00179 Italy Visual sustained attention directed to a location without moving the eyes (cover attention) enhanced the perception in that region. The effect of attention was measured on the visual evoked potential (VEP) to a grating continuously displayed in the left visual field. Both steady-state and transient VEPs were recorded. In both conditions a small target (a light changing colour) was presented either in the left or in the right visual field. The task of the subject was to count the number of colour changes, without moving the eyes from the central fixation point. Thus, attention was directed either to the left or to the right visual target while VEPs were recorded from the task-irrelevant grating on the left side. In agreement with previous observations, VEPs amplitude enhancement by attention was present on steady-state and transient experiments. Results go beyond previous findings showing that VEP in the attended condition had shorter latency than VEP in the unattended condition. The difference in latency ranged from 5 to 15 ms. Results are discussed in relation to the hypothesis of attention as a sensory gain control mechanism.