ERPs in long and short ISI dishabituation tasks : a comparison using PCA

The Orienting Reflex (OR) is an adaptive mechanism that focuses an organism's attention towards changes in the environment, and is particularly sensitive to stimulus novelty and significance. The Late Positive Complex (LPC) of the event-related potential (ERP) is thought to be a central analogue of the OR. The LPC contains several overlapping components (P3a, P3b, HabP3/NoveltyP3) that differ in latency, topography, and response characteristics. Using components of the LPC as our OR index, we explored whether the rate of stimulus presentation affected the OR, in the context of indifferent and significant (counting) stimuli