38 research outputs found
Onset and Offset as Determinants of the Simon Effect
We investigated the presence and the characteristics of the Simon effect for onset and offset targets when these stimuli are randomly intermixed. In Experiment 1, two possible target locations were occupied by an occluder. On onset trials, a target appeared above an occluder, while on offset trials one of the occluders disappeared, revealing the target underneath. In Experiment 2, four stimuli appeared randomly in six possible locations. On onset trials, a new stimulus appeared in an empty location while on offset trials, one of the initial stimuli disappeared. In both experiments, the Simon effect for onset and offset targets was characterized by similar size, time course and sequential modulation, suggesting similar sensorimotor interactions between target and response locations. However, the Simon effect in the current trials was more evident when the same type of target (onset or offset) was repeated on successive trials demonstrating the role of stimulus category in its modulation
Tool use modulates early stages of visuo-tactile integration in far space:Evidence from event-related potentials
The neural representation of multisensory space near the body is modulated by the active use of long tools in non-human primates. Here, we investigated whether the electrophysiological correlates of visuo-tactile integration in near and far space were modulated by active tool use in healthy humans. Participants responded to a tactile target delivered to one hand while an irrelevant visual stimulus was presented ipsilaterally in near or far space. This crossmodal task was performed after the use of either short or long tools. Crucially, the P100 components elicited by visuo-tactile stimuli was enhanced on far as compared to near space trials after the use of long tools, while no such difference was present after short tool use. Thus, we found increased neural responses in brain areas encoding tactile stimuli to the body when visual stimuli were presented close to the tip of the tool after long tool use. This increased visuo-tactile integration on far space trials following the use of long tools might indicate a transient remapping of multisensory space. We speculate that performing voluntary actions with long tools strengthens the representation of sensory information arising within portions of space (i.e. the hand and the tip of the tool) that are most functionally relevant to one's behavioural goals
On the spread of spatial attention in touch: Evidence from Event-Related Brain potentials
To investigate the distribution of tactile spatial attention near the current attentional
focus, participants were cued to attend to one of four body locations (hand or shoulder on the left or right side) to respond to infrequent tactile targets. In this narrow attention task, effects of spatial attention on the ERPs elicited by tactile stimuli delivered to the hands were compared as a function of the distance from the attentional focus (Focus on the hand vs. Focus on the shoulder). When participants focused on the hand, attentional modulations of the sensory-specific P100 and N140 components were followed by the longer latency Nd component. Notably, when participants focused on the shoulder, they were unable to restrict their attentional resources to the cued location, as revealed by the presence of reliable attentional modulations at the hands. This effect of attention outside the attentional focus was delayed and reduced compared to that observed within the attentional focus, revealing the presence of an attentional gradient. In addition, to investigate whether the size of the attentional focus modulated the effects of tactile spatial attention on somatosensory processing, participants also completed the Broad attention task, in which they were cued to attend to two locations (both the hand and the shoulder) on the left or right side. Attentional modulations at the hands emerged later and were reduced in the Broad compared to the Narrow attention task, suggesting reduced attentional resources for a wider attentional focus
Visual imagery vividness and mental rotation of characters:An event related potentials study
Recent behavioural evidence suggests that differences in the vividness of visual imagery (VVI) affect the way in which mental rotation (MR) tasks are accomplished. However, the role of VVI in MR tasks is still debated. We explored it using event-related brain potentials (ERPs) which allow to track the time course of MR processes with high temporal resolution. We assigned participants to two different groups based on their VVI and compared the rotation-related negativity (RRN), the electrophysiological correlate of MR. Accuracy did not differ in the two groups. However, the RRN offset was delayed in lower as compared to higher VVI individuals. The processing of MR as indexed by the RRN is longer in individuals with lower VVI, providing direct evidence for a role of VVI in MR processing
Searching on the back:Attentional selectivity in the periphery of the tactile field
Recent evidence has identified the N140cc lateralized component of event-related potentials as a reliable index of the deployment of attention to task-relevant items in touch. However, existing ERP studies have presented the tactile search array to participants' limbs, most often to the hands. Here, we investigated distractor interference effects when the tactile search array was presented to a portion of the body that is less lateralized and peripheral compared to the hands. Participants were asked to localize a tactile target presented among distractors in a circular arrangement to their back. The N140cc was elicited contralateral to the target when the singleton distractor was absent. Its amplitude was reduced when the singleton distractor was present and contralateral to the target, suggesting that attention was directed at least in part to the distractor when the singletons are on opposite sides. However, similar N140cc were observed when the singleton distractor was ipsilateral to the target compared to distractor absent trials. We suggest that when target and singleton distractor are ipsilateral, the exact localization of the target requires the attentional processing of all items on the same side of the array, similar to distractor absent trials. Together, these observations replicate the distractor interference effects previously observed for the hands, suggesting that analogous mechanisms guide attentional selectivity across different body parts
Cognitive conflict is an example of action-grounded cognition.
The aim of the present work was to show that cognitive conflict, an issue that has been widely studied within the boundaries of the classical cognitive approach, is a clear example of higher order cognition tied to perception and action. Examples of how the cognitive conflict arising from spatial correspondence tasks is highly grounded in body attributes and in environmental/situational factors are provided. Spatial performance is strongly modulated by handedness, prior experience and by social factors. In addition, in two experiments empirical findings are reported showing that the spatial correspondence effect is a function of the location of the dynamic event even when target location is in the opposite position. These results point to the notion that spatial performance is refractory from the intervention of higher order cognition
Age-associated delay in mental rotation
Age-associated slowing in mental rotation (MR) process has been documented in the literature. Particularly, the intercept of the response times (RTs) function of rotation angle has been consistently found to be larger in older than in younger adults. However, the intercept represents the speed of response in two distinct sub-processes of MR: the initial phase of stimulus encoding and the final phase of response selection and execution. Thus, it remains unclear which of these two sub-processes of MR is affected by age. To investigate this, we recorded event-related potentials in younger and older individuals during a letter rotation task. The onset of the rotation-related negativity (RRN), the electrophysiological correlate of MR, was delayed in older (n = 20; mean age = 20.1) as compared to younger participants (n = 20, mean age = 73.4). Consistent with this observation, additional analyses revealed that the RRN amplitude was modulated by rotation angle between 350 and 500 ms post-stimulus in younger adults (n = 26, mean age = 21.0), while this modulation only emerged in the later time window (500-650ms) in older participants (n = 26; mean age = 73.6). These results suggest that MR occurs later in older adults and demonstrate that the initial phase before MR proper is one source of the age-related slowing observed in MR tasks. Possible accounts for this age-associated delay include a prolonged phase of stimulus encoding and/or selective difficulties in directing attention away from the external stimulus towards its internal mental representation
The effect of perceptual load on tactile spatial attention:Evidence from event related potentials
To investigate whether tactile spatial attention is modulated by perceptual load, behavioural and electrophysiological measures were recorded during two spatial cuing tasks in which the difficulty of the target/non-target discrimination was varied (High and Low load tasks). Moreover, to study whether attentional modulations by load are sensitive to the availability of visual information, the High and Low load tasks were carried out under both illuminated and darkness conditions. ERPs to cued and uncued non-targets were compared as a function of task (High vs. Low load) and illumination condition (Light vs. Darkness). Results revealed that the locus of tactile spatial attention was determined by a complex interaction between perceptual load and illumination conditions during sensory-specific stages of processing. In the Darkness, earlier effects of attention were present in the High load than in the Low load task, while no difference between tasks emerged in the Light. By contrast, increased load was associated with stronger attention effects during later post-perceptual processing stages regardless of illumination conditions. These findings demonstrate that ERP correlates of tactile spatial attention are strongly affected by the perceptual load of the target/non-target discrimination. However, differences between illumination conditions show that the impact of load on tactile attention depends on the presence of visual information. Perceptual load is one of the many factors that contribute to determine the effects of spatial selectivity in touch