Temporal dynamics of contextual processing in the inferior colliculus of a rat model of autism: Sex- and age-dependent trajectories.

In autism, sensory differences have been linked to altered contextual processing and to how temporal structure supports the formation of regularities and predictions. Here, we examined how temporal and contextual auditory processing are shaped by sex, development, and prenatal valproic acid (VPA) exposure in the non-lemniscal inferior colliculus at low sound levels. Single-unit recordings from control and VPA-exposed rats were obtained using oddball and cascade paradigms, allowing dissociation of mismatch (iMM), repetition suppression (iRS), and prediction-error (iPE) components in both response magnitude and latency. In control animals, maturation selectively reorganized contextual and predictive processing in females, shifting responses toward reduced repetition suppression and increased prediction-error signaling. This shift was accompanied by longer response latencies, indicating a broader temporal integration window. Compared to male rats, adult females displayed prediction-driven, with reduced adaptation bias, of mismatch responses. In contrast, prenatal VPA exposure disrupted this sex- and age-dependent pattern, particularly in females, producing reduced response magnitude together with earlier response peaks. These findings reveal a female-specific reorganization of subcortical contextual processing and demonstrate that sex, age, and prenatal VPA exposure-related effects can dissociate response strength from temporal deployment. Collectively, our results highlight the role of temporal dynamics in contextual computation within the auditory midbrain and support the contribution of early subcortical circuits to autism-related sensory processing.