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We present neuropsychological evidence demonstrating that the binding of form elements into shapes dissociates from the binding of surface detail to shape. Data are reported from a patient with bilateral parietal lesions, GK, who manifests left-side visual extinction along with many illusory conjunctions when asked to discriminate both surface and form(More)
We explored the possibility of controlling a spacecraft simulator using an analogue Brain-Computer Interface (BCI) for 2-D pointer control. This is a difficult task, for which no previous attempt has been reported in the literature. Our system relies on an active display which produces event-related potentials (ERPs) in the user's brain. These are analysed(More)
The oddball protocol is often used in brain-computer interfaces (BCIs) to induce P300 ERPs, although, recently, some issues have been shown to detrimentally effect its performance. In this paper, we study a new periodic protocol and explore whether it can compete with the standard oddball protocol within the context of a BCI mouse. We found that the new(More)
In this paper we propose a brain-computer interface (BCI) mouse based on P300 waves in electroencephalogram (EEG) signals. The system is analogue in that at no point a binary decision is made as to whether or not a P300 was actually produced in response to the stimuli. Instead, the 2-D motion of the pointer on the screen, using a novel BCI paradigm, is(More)
Cross-modal illusory conjunctions (ICs) happen when, under conditions of divided attention, felt textures are reported as being seen or vice versa. Experiments provided evidence for these errors, demonstrated that ICs are more frequent if tactile and visual stimuli are in the same hemispace, and showed that ICs still occur under forced-choice conditions but(More)
Stimulus-locked, response-locked, and ERP-locked averaging are effective methods for reducing artifacts in ERP analysis. However, they suffer from a magnifying-glass effect: they increase the resolution of specific ERPs at the cost of blurring other ERPs. Here we propose an extremely simple technique-binning trials based on response times and then(More)
SUMMARY Some perceptual phenomena can interfere with character identification in Farwell and Donchin's P300-based speller paradigm [1]: attentional blink, repetition blindness and other effects caused by attentional limits. In the paper we discuss these and provide empirical evidence for one class of perceptual errors. INTRODUCTION Our ability of detecting(More)
Recent studies have indicated that acute exposure to low level radiofrequency (RF) electromagnetic fields generated by mobile phones affects human cognition. However, the relatively small samples used, in addition to methodological problems, make the outcomes of these studies difficult to interpret. In our study we tested a large sample of volunteers (168)(More)
In this paper we explore the use of evolutionary algorithms in a wrapper-based selection of features and the classification of P300 signals in Brain Computer Interfaces. In particular we focus on a paradigm that uses the P300 potential associated to particular visual stimuli for hands free text entering. In our experiments the GA has found new ways to(More)
The P300 is an endogenous event-related potential (ERP) that is naturally elicited by rare and significant external stimuli. P300s are used increasingly frequently in brain-computer interfaces (BCIs) because the users of ERP-based BCIs need no special training. However, P300 waves are hard to detect and, therefore, multiple target stimulus presentations are(More)