Retention is how the brain encodes information.

False

Memory encoding is how the brain encodes new information, Retention is when the brain transfers it from short term to long term storage and Retrieval is when it is recalled for use by our brain.

Retention is indeed how the brain encodes informaiton. Or rather, it could be said that retention is a way how the brain remembers things and enables us to recall them at a later stage in life. This isn't the case with people who have some sort of memory lesions.