Master the Biology Bash: 2025 MCAT Biological Systems Practice Challenge!

The primary function of the hippocampus is to encode information into long-term memory. This brain structure is critical for the formation of new memories and is particularly involved in spatial memory, which helps individuals navigate their environment. The hippocampus is also essential for declarative memory, which includes facts and events that can be consciously recalled.

When new information is received, it is processed and transformed into a format that can be stored in long-term memory, allowing for later retrieval. Damage to the hippocampus can lead to difficulties in forming new memories or recalling recent experiences, which underscores its vital role in the memory system.

The other options refer to functions that involve different parts of the brain or systems. Sensory information processing occurs mainly in the sensory cortices, regulating mood is primarily related to structures like the amygdala and the prefrontal cortex, and reflex actions are controlled by the spinal cord and brainstem pathways. Thus, encoding to long-term memory distinctly highlights the primary role of the hippocampus.