Dopamine modulates memory consolidation of discrimination learning in the auditory cortex

In Mongolian gerbils, the auditory cortex is critical for discriminating rising vs. falling frequency‐modulated tones. Based on our previous studies, we hypothesized that dopaminergic inputs to the auditory cortex during and shortly after acquisition of the discrimination strategy control long‐term memory formation. To test this hypothesis, we studied frequency‐modulated tone discrimination learning of gerbils in a shuttle box GO/NO‐GO procedure following differential treatments. (i) Pre‐exposure of gerbils to the frequency‐modulated tones at 1 day before the first discrimination training session severely impaired the accuracy of the discrimination acquired in that session during the initial trials of a second training session, performed 1 day later. (ii) Local injection of the D1/D5 dopamine receptor antagonist SCH‐23390 into the auditory cortex after task acquisition caused a discrimination deficit of similar extent and time course as with pre‐exposure. This effect was dependent on the dose and time point of injection. (iii) Injection of the D1/D5 dopamine receptor agonist SKF‐38393 into the auditory cortex after retraining caused a further discrimination improvement at the beginning of subsequent sessions. All three treatments, which supposedly interfered with dopamine signalling during conditioning and/or retraining, had a substantial impact on the dynamics of the discrimination performance particularly at the beginning of subsequent training sessions. These findings suggest that auditory‐cortical dopamine activity after acquisition of a discrimination of complex sounds and after retrieval of weak frequency‐modulated tone discrimination memory further improves memory consolidation, i.e. the correct association of two sounds with their respective GO/NO‐GO meaning, in support of future memory recall. In Mongolian gerbils, the auditory cortex is critical for discriminating rising vs. falling frequency‐modulated tones. Based on our previous studies, we hypothesized that dopaminergic inputs to the auditory cortex during and shortly after acquisition of the discrimination strategy control long‐term memory formation.