Hippocampus and memory
In this section, we'll discuss memory–focusing primarily on the role of the hippocampus in memory.
1) Start with this video:
2) Then, read this article: Know Your Brain - Hippocampus
3) Watch this video for a review of hippocampal anatomy:
4) Finally, answer these questions to test your understanding:
1. Which of the following is the primary output structure of the hippocampal formation?
- A. dentate gyrus
- B. subiculum
- C. CA3 region
- D. CA1 region
Show Answer
Correct answer: B
The subiculum serves as the primary output structure of the hippocampal formation. Information processed through the hippocampal circuit is funneled into the subiculum, which then sends projections to a wide range of targets, including the entorhinal cortex and other cortical and subcortical areas.
2. The hippocampus is often subdivided anatomically into 4 regions, designated CA1 through CA4. What does the CA stand for?
- A. cellular array
- B. cortical area
- C. central arch
- D. cornu ammonis
Show Answer
Correct answer: D
The structure of the hippocampus has been likened to the curved horn of a ram or the horns of the ancient Egyptian god Ammon and thus has been called Ammon’s horn or cornu ammonis. Accordingly, the hippocampus has been subdivided anatomically into 4 regions designated CA1 through CA4; the CA stands for cornu ammonis.
3. Long-term memory for factual knowledge, such as knowing that an axon carries electrical signals away from the cell body of a neuron, is an example of:
- A. implicit memory
- B. episodic memory
- C. sensory memory
- D. semantic memory
Show Answer
Correct answer: D
Declarative memory is sometimes called explicit memory, and it refers to memories we can consciously access and describe. This includes episodic memory, which involves events from our own lives—such as what you did yesterday—or semantic memory, which consists of facts and general knowledge, like knowing what an axon is.
4. Which of the following is considered a main site of initial processing in the hippocampal formation?
- A. subiculum
- B. CA1 region
- C. amygdala
- D. dentate gyrus
Show Answer
Correct answer: D
The dentate gyrus is a main site of initial processing in the hippocampal formation. It is thought to play a critical role in sorting information based on shared characteristics—a process sometimes called pattern separation.
5. The hippocampus (brain structure) was named for its resemblance to which marine animal?
- A. jellyfish
- B. starfish
- C. seahorse
- D. octopus
Show Answer
Correct answer: C
The word hippocampus comes from the Greek Hippokampos—hippos meaning “horse” and kampos meaning “sea monster.” The word eventually came to be used to describe a seahorse, and the hippocampus got its name because when you remove it from the brain, it vaguely resembles a seahorse.
