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The specific adaptation of neuronal responses to a repeated stimulus, which does not fully generalize to other stimuli, is called stimulus-specific adaptation (SSA).The SSA is thought to be with a mechanism for emphasizing rare and potentially interesting sensory events.Neurons in the auditory system from the inferior colliculus to the auditory cortex have been reported to show SSA to stimuli with different frequencies.The auditory system processes spatial information of the acoustic stimuli.In the present study, we investigated whether neurons in auditory cortex showed the phenomenon of SSA over sound stimuli located in different sources.We recorded single and multiunit neurons in auditory cortex of anaesthetized rats.The stimuli were noise bursts or tones presented toward different ears with oddball paradigm.(1) The majority of the cortical neurons showed the preference for the stimulus with novel position.(2) The firing rate of neurons was larger to the stimulus with novel frequency and position than that with the only position.The reason that neurons in auditory cortex showed across-ear stimulus-specific adaptation was probably that this adaptation to the different spatial information was segregated from the frequency information, so in the oddball paradigm the response to the deviant stimulus was not affected by the adaptation to the standard stimulus.