Electrophysiological alterations in a complex rat model of schizophrenia

• EEG phenotype characterization in a rat substrain related to schizophrenia/autism.
• ERPs showed significant changes in P2 latency and N1 amplitude.
• Acute ketamine treatment did not cause alterations in ERPs.
• Altered power of oscillations in different frequency bands was observed.
• Ketamine caused strain-dependent changes in the power of oscillations.

BackgroundPsychiatric disorders are frequently accompanied by changes in brain electrical oscillations and abnormal auditory event related potentials. The goal of this study was to characterize these parameters of a new rat substrain showing several alterations related to schizophrenia.MethodsMale rats of the new substrain, developed by selective breeding after combined subchronic ketamine treatment and postweaning social isolation, and naive Wistar ones group-housed without any interventions were involved in the present study. At the age of 3 months, animals were implanted with cortical electroencephalography electrodes. Auditory evoked potentials during paired-click stimuli and power of oscillation in different frequency bands were determined with and without acute ketamine (20 mg/kg) treatment.ResultsRegarding the auditory evoked potentials, the latency of P2 was delayed and the amplitude of N1 peak was lower in the new substrain. The new substrain showed increased power of oscillations in the theta, alpha and beta bands, while decreased power was detected in delta and gamma2 bands (52–70 Hz) compared with control animals. Acute ketamine treatment increased the gamma1 band (30–48 Hz) power in both groups, while it elicited significant changes only in the new substrain in the total power and in alpha, beta and gamma2 bands.ConclusionsThe validation of the translational utility of this new rat substrain by electrophysiological investigations revealed that these rats show abnormalities that may model a part of the neurophysiological deficits observed in schizophrenia.