A new method for recovering superposed waveforms when the evoked-response is longer than the interval between stimuli has been recently invented. The new method is called QSD (q-Sequence Deconvolution). QSD can recover brain responses not previously observed because standard evoked-response technique is limited to responses shorter than the period of the stimulus repetition-rate. This project will build a visual stimulator for recording superposed VEPs (Visual Evoked Potentials). The project will then test whether the VEP responds at stimulus repetition-rates, which overlap the VEP. If it does, then the potentials may differ from those seen at slower ? stimulation rates. ? ? The project will also test whether stimuli more complex than checkerboards provide any ? additional measure of brain function. ? ? This project is health related because evoked-responses are widely used for screening and ? diagnostic testing. If the stimulator provides previously-unrecorded VEPs, then it is possible ? that such potentials could be of scientific and clinical use. Because the potentials are obtained ? from scalp electrodes it is easy to utilize such evoked-responses for clinical testing. ? ? ?