Transitions in infant learning are modulated by dopamine within the amygdala

Behavioral transitions Young infant rats paradoxically prefer odors paired with shock but older pups learn aversions. This transition is amygdala- and corticosterone-dependent. Microarray results showed downregulated dopaminergic presynaptic function in the amygdala with preference learning. Corticosterone injected 8-day-old pups and untreated 12-day-old pups learn aversions and had dopaminergic upregulation in the amygdala. 8 day saline or corticosterone treated- or 12 day old untreated rat pups were trained with odor-shock pairings. Immediately after training pups were sacrificed and the amygdala dissected out. Controls were unpaired shock-odor groups.Paired and unpaired groups were processed together for each experimental condition. Paired and unpaired data were compared by ranked products.