**Core Concept**
The hippocampus plays a crucial role in forming and consolidating new memories, particularly those related to emotions and experiences. Damage to this region can lead to significant impairments in memory formation and recall.

**Why the Correct Answer is Right**
Hippocampal lesions typically result in anterograde amnesia, a condition characterized by the inability to form new memories. This is due to the hippocampus's involvement in the process of consolidation, where short-term memories are converted into long-term ones. The hippocampus is rich in neurons that release the neurotransmitter acetylcholine, which facilitates the transmission of signals between neurons involved in memory formation. Damage to the hippocampus disrupts this process, leading to impaired memory consolidation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because hippocampal lesions do not typically result in retrograde amnesia, which is the loss of memories formed before the lesion occurred.
**Option B:** This option is incorrect because hippocampal lesions do not primarily affect motor function or coordination, which are more closely related to damage to the cerebellum or motor cortex.
**Option C:** This option is incorrect because hippocampal lesions do not typically result in aphasia, which is the loss of language skills due to damage to areas of the brain involved in language processing, such as Broca's area or Wernicke's area.

**Clinical Pearl / High-Yield Fact**
The hippocampus is particularly vulnerable to damage due to its location in the temporal lobe, where it is susceptible to injury from head trauma, infections, or vascular events. As a result, patients with hippocampal lesions often exhibit significant impairments in memory formation and recall.

**Correct Answer:** D. Anterograde amnesia