목적: Central auditory pathway is known to be established during postnatal period called critical period, shaped by experience and sensory inputs, leaving the brain highly susceptible to environmental insults at this time. Phthalate is a known neurotoxic material, which is widely used in hundreds of consumer products including plastic toys. It has been reported to be associated with poor attentional performances of childhood and many infant neurobehaviors. In the study, we investigated the effects of neonatal phthalate exposure on the development of auditory temporal processing. 방법:Neonatal Sprague-Dawley rats were randomly assigned into two groups: rats in the phthalate group (n = 6) were injected with 10 mg/kg phthalate, prepared with corn oil and control rats (n = 6) were injected with same amount of corn oil only. Phthalate or corn oil was given once per day (i.p. at noon) from P8 to P28. At P30, Auditory Brainstem Response (ABR) and Gap Prepulse Inhibition of Acoustic Startle response (GPIAS) at each gap duration (2, 5, 10, 20, 50 and 80ms) were measured, and gap detection threshold (GDT) was calculated. These outcome measurements were compared between two groups. 결과:Hearing thresholds were evaluated by ABR tests and there were no significant differences in hearing thresholds at all frequencies between two groups. Regarding GPIAS, no significant difference was observed at small and large gap durations. However at medium gap duration (20ms), there was a difference between two groups with a marginal significance (p = 0.065). GDT was calculated from the GPIAS data. Mean GDTs for phthalate exposure group and control group were 53.3ms and 20.0ms respectively and it was smaller in control group than in experimental group with statistical significance (p = 0.022). 결론:Neonatal phthalate exposure may impair the normal development of auditory temporal processing without inducing a peripheral hearing loss.