Validation of a model of itch induction for brain positron emission tomography studies using histamine iontophoresis.

Skin-brain signalling in itch reactions has been demonstrated with neuroimaging techniques showing specific brain activation. With positron emission tomography (PET), the itch model used must be adapted to technical and practical constraints. The technique of itch induction by histamine iontophoresis enables modulation of the sensation via the electrical charge applied.

Stimulus complexity and prospective timing: clues for a parallel process model of time perception.

Whereas many studies have considered the role of attention in prospective timing, fewer have established relations between movement complexity and prospective timing. The present study aims at assessing to what extent motion complexity interferes with prospective timing and at delineating a neuropsychophysical plausible model. We have thus designed a visual paradigm presenting stimuli in sequential pairs (reference comparison interval).