Distinct millisecond-scale click-train patterns evoke discriminable behavioral and neural responses in humans and rats

Natural sounds are shaped by both spectral content and temporal patterning. Here we ask whether click trains with the same mean inter-click interval, but different millisecond-scale temporal patterns evoke distinct behavioral and neural responses. Human listeners discriminated several such click-train patterns, and human EEG revealed context-dependent deviance-related responses. Awake rats showed analogous cortical response differences at the ECoG level. Along the IC–MGB–A1 pathway, unit recordings revealed weak oddball/context sensitivity in IC, intermediate sensitivity in MGB, and stronger stimulus-specific adaptation in A1. Reversible inactivation of the auditory cortex reduced MGB sensitivity, indicating a contribution of corticothalamic feedback. Further A1 layer analyses showed stronger effects in supragranular than deep cortical layers. Together, these results show that distinct click-train temporal patterns are differentially represented across the auditory system, with stronger sensitivity emerging in higher auditory structures.