As expected, isolates were less able to gate sensory stimuli in the prepulse inhibition test compared to socially-reared rats. Prepulse inhibition is an adaptive mechanism that permits identification of potentially distracting/unimportant stimuli so that responding is averted to those with more relevance (for review see Koch and Schnitzler, 1997). Handling isolates partially ameliorated the deficit in prepulse inhibition exhibited by isolates, but did not fully compensate for it. In line with our data, different strains of rats with dissimilar anxiety-like traits respond uniquely in the prepulse inhibition test (van den Buuse, 2003). Even though the acoustic startle response and prepulse inhibition are intertwined processes, the neurobiology mediating the two phenomena are suggested to be distinct (Li et al., 2009). We found the overall pre-attentional responsiveness of isolates to the startle stimulus was unaltered. Together, these data suggest pre-attentional deficits of isolates are somewhat reversible through environmental manipulations.
