The effect of stimulus expectancy on dishabituation of auditory evoked potentials.

OBJECTIVES

Having foreknowledge of the type and timing of sensory stimulation modulates the electrophysiological response and can result in short-term habituation. Here we explore if dishabituation is similarly affected.

METHODS

Seventeen healthy subjects were tested with five different auditory stimuli paradigms to see if knowledge of the stimulus train length and/or deviant stimulus affects the amount of dishabituation of auditory evoked potentials. Furthermore it was determined if the degree of difference between the repeating stimulus and deviant stimulus affected the amount of dishabituation.

RESULTS

Stimulus complexity is the main determinant of the degree of dishabituation, followed by lack of knowledge about train length. Not knowing the deviant stimulus has little or no effect on dishabituation. Also, P200 is the most affected by expectancy and P50 not at all.

CONCLUSIONS

Foreknowledge of the type and timing of sensory stimulation modulates the degree of dishabituation.

SIGNIFICANCE

Previous reports have shown that expectancy does affect (certain) evoked potential components. Here we extend this knowledge to the effect of expectancy on dishabituation.