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Visual target selection and motor planning define attentional enhancement at perceptual processing stages.

Collins T, Heed T, Röder B - Front Hum Neurosci (2010)

Bottom Line: Extracting information from the visual field can be achieved by covertly orienting attention to different regions, or by making saccades to bring areas of interest onto the fovea.While much research has shown a link between covert attention and saccade preparation, the nature of that link remains a matter of dispute.We examined attentional orienting by recording event-related potentials (ERPs) to task-irrelevant visual probes flashed during saccade preparation at four equidistant locations including the visual target location and the upcoming motor endpoint.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Psychologie de la Perception, CNRS, Université Paris Descartes Paris, France.

ABSTRACT
Extracting information from the visual field can be achieved by covertly orienting attention to different regions, or by making saccades to bring areas of interest onto the fovea. While much research has shown a link between covert attention and saccade preparation, the nature of that link remains a matter of dispute. Covert presaccadic orienting could result from target selection or from planning a motor act toward an object. We examined the contribution of visual target selection and motor preparation to attentional orienting in humans by dissociating these two habitually aligned processes with saccadic adaptation. Adaptation introduces a discrepancy between the visual target evoking a saccade and the motor metrics of that saccade, which, unbeknownst to the participant, brings the eyes to a different spatial location. We examined attentional orienting by recording event-related potentials (ERPs) to task-irrelevant visual probes flashed during saccade preparation at four equidistant locations including the visual target location and the upcoming motor endpoint. ERPs as early as 130-170 ms post-probe were modulated by attention at both the visual target and motor endpoint locations. These results indicate that both target selection and motor preparation determine the focus of spatial attention, resulting in enhanced processing of stimuli at early visual-perceptual stages.

No MeSH data available.


Related in: MedlinePlus

(A) Time course of saccadic adaptation (saccade direction (filled symbols) and amplitude (open symbols) as a function of trial number) in two typical participants. The shaded area corresponds to the adaptation phase. Each point corresponds to one saccade and only upward saccades are shown. The curve corresponds to a running average with a 50-trial sliding window. (B) Distribution of saccade directions in the pre-adaptation (gray) and post-adaptation (black) phases relative to the four probe locations, over all 14 participants. Dashed lines represent ±SEM.
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Figure 2: (A) Time course of saccadic adaptation (saccade direction (filled symbols) and amplitude (open symbols) as a function of trial number) in two typical participants. The shaded area corresponds to the adaptation phase. Each point corresponds to one saccade and only upward saccades are shown. The curve corresponds to a running average with a 50-trial sliding window. (B) Distribution of saccade directions in the pre-adaptation (gray) and post-adaptation (black) phases relative to the four probe locations, over all 14 participants. Dashed lines represent ±SEM.

Mentions: Saccades were directed to one of two visual targets, 8° above or below central fixation, based on the color of the fixation point. During the pre-adaptation phase, saccade endpoints were concentrated near the upper and lower targets with very few direction errors (<1% in each participant), and presented an undershoot of the target typical for saccades (Becker, 1972) (Figure 2A). During the adaptation phase, the upper target stepped to a location 45° to the left of central fixation while the saccade was in mid-flight. Saccade endpoints shifted accordingly; this shift was induced during the adaptation phase (gray area in Figure 2A) and maintained during the post-adaptation phase. To determine the number of trials necessary for adaptation to emerge, the time course (saccade direction as a function of trial) was analyzed with the following method. Linear regressions on the relationship between saccade direction and trial number T were performed, by varying the limits Tmin and Tmax. First, Tmin was fixed as the first trial of the pre-adaptation phase and Tmax varied, each time taking one more trial into account. Each trial is thus associated with a particular slope value. During the pre-adaptation phase, the slope is close to 0, but when saccade direction changes during the adaptation phase, the slope exhibits a breaking point which corresponds to the onset of adaptation. Second, Tmax was fixed as the last trial of the post-adaptation phase and Tmin varied. Again, the slope of the linear function exhibits a breaking point, which corresponds to the offset of adaptation. On average, saccade direction needed 132 ± 71 trials (range 45–251) to become adapted, which is well within the normally reported range for humans (Hopp and Fuchs, 2004). Figure 2B presents the pre- and post-adaptation endpoint distributions over all participants.


Visual target selection and motor planning define attentional enhancement at perceptual processing stages.

Collins T, Heed T, Röder B - Front Hum Neurosci (2010)

(A) Time course of saccadic adaptation (saccade direction (filled symbols) and amplitude (open symbols) as a function of trial number) in two typical participants. The shaded area corresponds to the adaptation phase. Each point corresponds to one saccade and only upward saccades are shown. The curve corresponds to a running average with a 50-trial sliding window. (B) Distribution of saccade directions in the pre-adaptation (gray) and post-adaptation (black) phases relative to the four probe locations, over all 14 participants. Dashed lines represent ±SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2836756&req=5

Figure 2: (A) Time course of saccadic adaptation (saccade direction (filled symbols) and amplitude (open symbols) as a function of trial number) in two typical participants. The shaded area corresponds to the adaptation phase. Each point corresponds to one saccade and only upward saccades are shown. The curve corresponds to a running average with a 50-trial sliding window. (B) Distribution of saccade directions in the pre-adaptation (gray) and post-adaptation (black) phases relative to the four probe locations, over all 14 participants. Dashed lines represent ±SEM.
Mentions: Saccades were directed to one of two visual targets, 8° above or below central fixation, based on the color of the fixation point. During the pre-adaptation phase, saccade endpoints were concentrated near the upper and lower targets with very few direction errors (<1% in each participant), and presented an undershoot of the target typical for saccades (Becker, 1972) (Figure 2A). During the adaptation phase, the upper target stepped to a location 45° to the left of central fixation while the saccade was in mid-flight. Saccade endpoints shifted accordingly; this shift was induced during the adaptation phase (gray area in Figure 2A) and maintained during the post-adaptation phase. To determine the number of trials necessary for adaptation to emerge, the time course (saccade direction as a function of trial) was analyzed with the following method. Linear regressions on the relationship between saccade direction and trial number T were performed, by varying the limits Tmin and Tmax. First, Tmin was fixed as the first trial of the pre-adaptation phase and Tmax varied, each time taking one more trial into account. Each trial is thus associated with a particular slope value. During the pre-adaptation phase, the slope is close to 0, but when saccade direction changes during the adaptation phase, the slope exhibits a breaking point which corresponds to the onset of adaptation. Second, Tmax was fixed as the last trial of the post-adaptation phase and Tmin varied. Again, the slope of the linear function exhibits a breaking point, which corresponds to the offset of adaptation. On average, saccade direction needed 132 ± 71 trials (range 45–251) to become adapted, which is well within the normally reported range for humans (Hopp and Fuchs, 2004). Figure 2B presents the pre- and post-adaptation endpoint distributions over all participants.

Bottom Line: Extracting information from the visual field can be achieved by covertly orienting attention to different regions, or by making saccades to bring areas of interest onto the fovea.While much research has shown a link between covert attention and saccade preparation, the nature of that link remains a matter of dispute.We examined attentional orienting by recording event-related potentials (ERPs) to task-irrelevant visual probes flashed during saccade preparation at four equidistant locations including the visual target location and the upcoming motor endpoint.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire Psychologie de la Perception, CNRS, Université Paris Descartes Paris, France.

ABSTRACT
Extracting information from the visual field can be achieved by covertly orienting attention to different regions, or by making saccades to bring areas of interest onto the fovea. While much research has shown a link between covert attention and saccade preparation, the nature of that link remains a matter of dispute. Covert presaccadic orienting could result from target selection or from planning a motor act toward an object. We examined the contribution of visual target selection and motor preparation to attentional orienting in humans by dissociating these two habitually aligned processes with saccadic adaptation. Adaptation introduces a discrepancy between the visual target evoking a saccade and the motor metrics of that saccade, which, unbeknownst to the participant, brings the eyes to a different spatial location. We examined attentional orienting by recording event-related potentials (ERPs) to task-irrelevant visual probes flashed during saccade preparation at four equidistant locations including the visual target location and the upcoming motor endpoint. ERPs as early as 130-170 ms post-probe were modulated by attention at both the visual target and motor endpoint locations. These results indicate that both target selection and motor preparation determine the focus of spatial attention, resulting in enhanced processing of stimuli at early visual-perceptual stages.

No MeSH data available.


Related in: MedlinePlus