This chapter considers how the P50, Nl, and P300 components of the auditory event-related brain potential (ERP) are related to startle. Although both blink and ERPs can be elicited by startling noises, blinks are muscular and ERPs are neural. Comparing startle blinks and ERPs reveals at what point the neural processes supporting them diverge. Each ERP component is evaluated against variables known to affect startle-stimulus intensity, stimulus rise time, habituation, and leading stimuli presented at both short and long lead intervals. ERPs recorded in startle modification paradigms suggest that the relationship between startle blinks and ERPs is weak. P50, Nl, and P300 are all inhibited by short lead intervals, but with different time courses from startle; only the fronto-central P300 is facilitated with long lead intervals.
Psychophysiologists tend to specialize. Those who study event-related brain potentials (ERPs) usually do not study startle, perhaps because startle produces tremendous blinks and muscle contraction “artifacts” on the scalp, often much larger than ERPs. Yet startling stimuli elicit ERPs, and by comparing blinks and ERPs elicited by startling stimuli, we will learn about the dependence and interdependence of the neural pathways that support these two responses.
Developments Encouraging Study of Startle with ERPs
Two developments have encouraged looking at ERPs in conjunction with startle. First, parallels have been observed between startle modification and suppression of P50; schizophrenics have been found to differ from normals in both startle inhibition by lead stimuli at short lead intervals and P50 suppression (Chapter 11).
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