Prepulse inhibition of the startle blink reflex is modulated during a memory task requiring prepulses to be encoded for later report

Prepulse inhibition (PPI) of the startle blink reflex in humans can be modulated by selective attention to the prepulse. The present experiment used a memory task to determine whether the encoding of information for later report can modulate PPI. Participants were briefly presented with a display of one or three letters followed by a pattern mask and asked to make a delayed report of the letter(s) shown. Memory recall was better in the 1-letter condition than in the 3-letter condition. Prepulse inhibition was greater in the 3-letter condition than in the 1-letter condition at lead intervals of 120 and 240 ms following the onset of the letter display. Blink modulation did not differ between the letter conditions at lead intervals of 120, 240, 360, or 2600 ms following the mask, ruling out other explanations (e.g., rehearsal) for the earlier difference in PPI. The results suggest that the short-term consolidation of memory, and possibly any cognitive process that requires access to a theoretical limited capacity central processing mechanism modulates PPI.