One of the major questions in psychology is whether associative and nonassociative learning are fundamentally different or whether they involve similar processes and mechanisms. We have addressed this question by comparing mechanisms of a nonassociative form of learning, sensitization, and an associative form of learning, classical conditioning of…

Long-term but not short-term memory and synaptic plasticity in many brain areas require neurotrophin signaling, transcription, and epigenetic mechanisms including DNA methylation. However, it has been difficult to relate these cellular mechanisms directly to behavior because of the immense complexity of the mammalian brain. To address that…

Fear-relevant stimuli such as snakes and spiders are thought to capture attention due to evolutionary significance. Classical conditioning experiments indicate that these stimuli accelerate learning, while instructed extinction experiments suggest they may be less responsive to instructions. We manipulated stimulus type during instructed aversive…