Objective: The P300 event-related brain potential (ERP) was elicited with a
uditory and visual stimuli in a separate session of a 3 stimulus oddball pa
radigm, and the scalp topography was assessed with 15 electrode locations.
Methods: Target (0.10), standard (0.80), and infrequent non-target (0.10) s
timuli in the auditory task were 2000, 1000 and 500 Hz tone, and in the vis
ual task, 'X','O', and 'H', respectively. The stimuli were presented in a r
andom series, once every 2 s, and participants responded only to the target
(N = 12).
Results: Target stimuli elicited larger P300 components than non-target did
in both stimulus modalities. For both target and non-target stimuli, P300
amplitude was larger and latency longer for the visual compared with the au
ditory stimulus. Analysis of normalized P300 amplitude data indicated that
the target and non-target P300s from both modalities had identical topograp
hy.
Conclusion: The findings suggest that both target and non-target stimuli in
3 stimulus oddball paradigm elicited the same type of P300 (P3b) for both
stimulus modalities. (C) 1999 Elsevier Science Ireland Ltd. All rights rese
rved.