The anxiolytic effect on the fear-potentiated startle is not due to a non-specific disruption.

In the present study, the effects of alprazolam, chlordiazepoxide, ethanol and haloperidol in the strychnine-potentiated startle response paradigm were investigated. Because strychnine increases control startle levels without fear-conditioning, no central state of fear exists. When anxiolytic drugs reduce the fear-induced potentiation of the startle response without reducing the strychnine-induced startle potentiation, their attenuating effect on startle potentiation in the fear-potentiated startle response paradigm can more likely be attributed to their anxiolytic properties. The selected drugs, which effectively reduced the fear-induced startle potentiation in an earlier study, indeed did not selectively affect the strychnine-induced startle potentiation, supporting the notion that the dose-dependent reduction of startle potentiation due to anxiolytic drugs in the fear-potentiated startle response paradigm does not reflect a "non-specific" disruption of startle behavior.