In his book, Sleep and Affect: Assessment, Theory, and Clinical Implications, Matthew Felder explains how sleep deprivation affects the brain and specifically the part of the brain that controls emotions (qtd. in the room). In an interview with the Huffington Post, he said: “Current thinking suggests that the impact of sleep loss on emotions is likely very complex. A key idea is that lack of sleep impairs the functioning of the prefrontal cortex region of the brain. This region of the brain is involved in complex behavior and thinking, including the regulation of emotional experience. Therefore, it is likely that dysfunction of the prefrontal cortex plays a critical role in the increased emotions seen in sleep-deprived people, because our nervous system is less able to reduce emotions once they have been triggered. (quoted in Hall). So, apart from lack of concentration in class, lack of sleep can be a serious problem and cause a lot of harm to everyone.