Long term memory lasts for longer periods (even for life time) and can hold much more information than the short term memory. The two types of long term memory are,
• Declarative or explicit memory
• Implicit or non-declarative memory
Declarative memory or explicit memory involves the intentional remembering. Non-random eye movement sleep (NREM) is associated with explicit memory.
Implicit memory or the non-declarative memory involves the unintentional remembering. The amygdala is associated with the non-declarative memory. Random eye movement sleep (REM) is associated with implicit memory.
Thus, the blank can be filled with explicit; implicit.