Accession Number : AD0771701

Title :   Evoked Cortical Potentials and Information Processing.

Descriptive Note : Annual rept. no. 1, 1 Jun-31 Dec 73,


Personal Author(s) : Andreassi,John L. ; Okamura,Hirohisa

Report Date : 31 DEC 1973

Pagination or Media Count : 106

Abstract : The report summarizes the approaches and findings of four experimental studies. The first study was concerned with the nature of the visual evoked potential (VEP) under conditions in which subjects (Ss) made numerosity estimates of rapidly presented small and large numbers of objects. The findings indicate shorter latency VEPs from the left occipital hemisphere when S's estimated larger numbers of objects. In the second experiment only a moderate range of numbers were tested (10, 16 or 22 objects). This time VEPs with the largest number objects showed longer latencies than with the smaller numbers. The effects of three pure tones upon the auditory evoked potential (AEP) was the focus of Experiment III. Sound frequencies of 50 Hz, 500 Hz and 2,500 Hz did not result in different AEPs for the Ss tested. Experiment IV examined the effects of simultaneous stimulation in two sensory modalities upon the AEP and VEP and speed of reaction time (RT). It was concluded that bisensory stimulation (auditory and visual) resulted in faster RT's than to visual stimuli alone. (Modified author abstract)

Descriptors :   *Psychophysiology, *Electrophysiology, *Brain, Senses(Physiology), Reaction(Psychology), Auditory perception, Visual perception

Subject Categories : Psychology
      Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE