Stronger auditory steady-state responses in male mice

Brain oscillations, whether spontaneous or evoked, may serve as biomarkers for diagnosing or even predicting psychiatric disorders (Mathalon and Sohal, 2015). The state of brain oscillations is believed to reflect the balance between excitation and inhibition in neural networks (Kim et al., 2015). As neurotransmission is significantly influenced by sex hormones (Krolick et al., 2018), it is reasonable to expect sex differences in brain oscillations between males and females. However, there is a lack of data, particularly in the field of animal research (Shansky and Murphy, 2021). Therefore, in this study aims to investigate sex differences in brain oscillations, both spontaneous and evoked. Electrocorticographic (ECoG) recordings were used to assess brain activity in spontaneous mode or when oscillations induced by brief auditory stimuli, method known as auditory steady-state responses (ASSRs). Although no significant differences were found in spontaneous oscillations of a wide range of frequencies, ASSRs evoked at 40 Hz showed higher brain synchronisation in male mice compared to female mice. Therefore, our findings suggest that sex may influence the generation of ASSRs, and this should be taken into consideration when assessing ASSRs in both male and female mice.Study was supported by the Research Council of Lithuania (09.3.3.-LMT-K-712-25-0057, U.J.), IBRO Return Home Fellowship (R.G.), IBRO Early Career Award and MJJ (Marius Jakulis Jason) fellowship (R.G.).