Smell Triggers Memory
A smell can bring on a flood of memories, influence people's moods and even affect their work performance. The olfactory bulb is part of the limbic system, an area which is closely associated with memory and feeling, sometimes called the "emotional brain." Therefore, smell can initiate recalling memories and powerful responses almost instantaneously.
The olfactory bulb has intimate access to the amygdala, an area of the brain which processes emotion, as well as the hippocampus, which is responsible for associative learning. Despite the tight wiring, however, smells would not trigger memories if it weren't for conditioned responses.