Damage to the hippocampus is most likely to impair
a. memory.
b. balance.
c. sleep.
d. breathing.
The correct answer and explanation is :
The correct answer is: a. memory.
Explanation (300+ words):
The hippocampus is a vital structure in the brain located within the temporal lobe and is part of the limbic system, which is associated with emotions and memory. Among its many functions, the most critical is its role in the formation, organization, and retrieval of new memories.
Damage to the hippocampus primarily results in memory impairments, especially affecting the ability to form new declarative memories—those related to facts and events (also called explicit memories). Individuals with hippocampal damage may experience anterograde amnesia, which is the inability to create new memories following the damage. In some cases, retrograde amnesia may also occur, affecting the recall of past memories that were not fully consolidated.
One of the most well-known cases involving hippocampal damage is Patient H.M. (Henry Molaison). After undergoing surgery to remove parts of his hippocampi to control severe epilepsy, H.M. lost the ability to form new long-term memories, although his short-term memory and intelligence remained intact. This case provided strong evidence that the hippocampus is essential for converting short-term memories into long-term memories.
In contrast, the other options are linked to different brain regions:
- b. Balance is primarily controlled by the cerebellum, which helps coordinate movement and maintain posture and equilibrium.
- c. Sleep regulation involves multiple brain areas, particularly the hypothalamus, which controls the sleep-wake cycle through the suprachiasmatic nucleus.
- d. Breathing is regulated by the brainstem, specifically the medulla oblongata and pons, which control automatic functions like respiration and heart rate.
Therefore, while the brain is highly interconnected, damage specifically to the hippocampus is most closely associated with memory dysfunction, not balance, sleep, or breathing. Recognizing the specialized roles of different brain structures is key in understanding how various neurological injuries affect behavior and bodily functions.