Hippocampus Thomas Henry Huxley and Richard Owen, satirised as the Great Hippocampus Question. The term hippocampus minor fell from use in anatomy textbooks, and was officially removed in the Nomina Anatomica of 1895. Today, the structure is just called the hippocampus, with the term "Cornu Ammonis" surviving in the names of the hippocampal subfields CA1-CA4. The term "limbic system" was introduced in 1952 by Paul MacLean to describe the set of structures that line the edge of the cortex (Latin "limbus" meaning "border"): These include the hippocampus, cingulate cortex, olfactory cortex, and amygdala. Paul MacLean later suggested that the limbic structures
Long-term memory task, a task closely comparable to tasks typically applied for testing human declarative memory: It is a one-trial task, hippocampus-dependent, not stressful and can be repeated within the same animal. Sleep deprivation reduces vigilance or arousal levels, affecting the efficiency of certain cognitive functions such as learning and memory. The theory that sleep benefits memory retention is not a new idea. It has been around since Ebbinghaus's experiment on forgetting in 1885. More recently studies have been done by Payne and colleagues and Holtz and colleagues. In Payne and colleague's experiment participants were randomly selected and split into two groups.