Mental fatigue before physical tiredness after poor sleep

After experiencing disrupted sleep, I've noticed that the first aspect to be affected is not my energy levels but rather my mental clarity. Even though I feel awake, decision-making becomes more difficult, my focus diminishes, and even small tasks require more effort. This seems to occur more frequently after fragmented sleep than when I get less total sleep time.Do others experience mental fatigue before feeling physically tired? What kinds of sleep patterns tend to cause this for you?