Studies of concurrent central, and autonomic activity
using a conventional event-related potential (ERP) oddball
paradigms, are considered useful in elucidating the relationship
between central and autonomic responses, but the autonomic
response tends to overlap. A new method was used to decompose
and score overlapping skin conductance responses (SCR).
This method enabled examination of dynamic relationships
of phasic SCR, prestimulus electroencephalogram (EEG),
and ERP to auditory target stimuli in 50 normal adults.
SCR amplitude was negatively correlated to EEG and N200
amplitude. The SCR amplitude changes over time exhibited
an exponential decline opposite to those of N200,
alpha, and beta. All the fitted exponential functions had
a time constant of 1–2 min. The findings suggest
that a N200 component, active in the auditory sensory discrimination,
is concomitant with the SCR. The narrow range of the time
constant may provide a clue to the conjoint processes underlying
central and autonomic adaptive functions.