Action goal selection and motor planning can be dissociated by tool use.

The preparation of eye or hand movements enhances visual perception at the upcoming movement end position. The spatial location of this influence of action on perception could be determined either by goal selection or by motor planning. We employed a tool use task to dissociate these two alternatives.

Interactions of different body parts in peripersonal space: how vision of the foot influences tactile perception at the hand.

The body schema, a constantly updated representation of the body and its parts, has been suggested to emerge from body part-specific representations which integrate tactile, visual, and proprioceptive information about the identity and posture of the body. Studies using different approaches have provided evidence for a distinct representation of the visual space approximately 30 cm around the upper body, and predominantly the hands, termed the peripersonal space. In humans, peripersonal space representations have often been investigated with a visual-tactile crossmodal congruency task.

On the relationship between slow cortical potentials and BOLD signal changes in humans.

This review summarizes experimental studies that investigated the relationship between DC-recorded slow event-related potentials (slow waves) of the electroencephalogram (EEG) and the hemodynamic BOLD response, as measured with functional magnetic resonance imaging (fMRI). Slow waves have been found to accompany a large number of cognitive processes in a systematic and topographically specific way, and have thus been successfully employed in psychophysiological experiments to dissociate cognitive functions by means of their slow wave topography. Recently, however, several independent studies, using different experimental paradigms, suggest the existence of another feature of slow waves, i.

Developmental vision determines the reference frame for the multisensory control of action.

Both animal and human studies suggest that action goals are defined in external coordinates regardless of their sensory modality. The present study used an auditory-manual task to test whether the default use of such an external reference frame is innately determined or instead acquired during development because of the increasing dominance of vision over manual control. In Experiment I, congenitally blind, late blind, and age-matched sighted adults had to press a left or right response key depending on the bandwidth of pink noise bursts presented from either the left or right loudspeaker.

Spatial remapping of touch: confusion of perceived stimulus order across hand and foot.

The "body schema," a spatial representation of the body in its environment, has been suggested to be an emergent property of a widespread network of effector-specific frontal and parietal areas, many of which integrate sensory input from the different modalities. On a behavioral level, such multimodality has been shown with temporal order judgment tasks, in which participants decide which of the two hands received a tactile stimulus first. The accuracy of these judgments is influenced by body posture, indicating that tactile stimuli are not simply represented in an anatomical reference frame, but are transformed into external spatial coordinates.

Tight covariation of BOLD signal changes and slow ERPs in the parietal cortex in a parametric spatial imagery task with haptic acquisition.

The present study investigated the relation of brain activity patterns measured with functional magnetic resonance imaging (fMRI) and slow event-related potentials (ERPs) associated with a complex cognitive task. A second goal was to examine the neural correlates of spatial imagery of haptically--instead of visually--acquired representations. Using a mental image scanning task, spatial imagery requirements were systematically manipulated by parametrically varying the distance between haptically acquired landmarks.

Influence of visual information on the auditory median plane of the head.

When determining the position of sounds, people perceive their subjective auditory median plane of the head (SAMP) displaced towards the side to which the head is turned. The present study investigated the influence of visual input on this effect. A group of congenitally blind and two groups of sighted adults, one with eyes open, one with eyes closed, adjusted the location of a tone presented through headphones in such a way that they perceived it to originate at their SAMP, both with the head straight ahead and turned 60 degrees to the right.