Context: Neptune's dark spots are thought to occur in the troposphere at lower altitudes than the brighter cloud features, so they appear as holes in the upper cloud decks. As they are stable features that can persist for several months, they are thought to be vortex structures. Often associated with dark spots are brighter, persistent methane clouds that form around the tropopause layer. The persistence of companion clouds shows that some former dark spots may continue to exist as cyclones even though they are no longer visible as a dark feature. Dark spots may dissipate when they migrate too close to the equator or possibly through some other unknown mechanism.

Question: Where are Neptune's dark spots thought to occur? 
Answer: in the troposphere

Question: What do Neptune's dark spots appear as in the cloud decks? 
Answer: holes

Question: Since Neptune's dark spots persist for several months, what are they thought to be?
Answer: vortex structures

Question: What on Neptune are associated with dark spots that are brighter?
Answer: methane clouds

Question: When Neptune's dark spots migrate too close to the equator, what do they do?
Answer: dissipate

Question: Where are Neptune's light spots thought to occur?
Answer: Unanswerable

Question:  What do Neptune's light spots appear as in the cloud decks?
Answer: Unanswerable

Question: Since Neptune's light spots persist for several months, what are they thought to be?
Answer: Unanswerable

Question:  What on Neptune are associated with light spots that are brighter?
Answer: Unanswerable

Question: When Neptune's light spots migrate too close to the equator, what do they do?
Answer: Unanswerable