A part of the brain called the hippocampus is thought to be crucial for learning and memory and implicated in many incurable disorders ranging from Autism to Alzheimer's. Hence, it is crucial to understand how the hippocampus works. Decades of research shows that hippocampal damage in humans causes loss of episodic or autobiographical memory. But, such memory traces in hippocampal single neurons are hard to find. Instead research in the rodent hippocampus shows that the neurons encode spatial maps, or place cells. Place cells are common in rodents but rare in humans or nonhuman primates.