Episodic Memory

movement sleep, especially slow wave sleep, and the processes that take place in the hippocampus during this type of sleep (Payne et al., 2008). In a study conducted by Payne et al. (2008), it was found that sleep that involves rapid eye movement also involves increased response in the limbic system. However, unlike non-rapid eye movement sleep that promotes certain types of hippocampal processes (Drosopoulos et al., 2013), rapid eye movement sleep brings about enhanced behavior in the amygdala, the part of the limbic system that is necessary in the processing of emotionally significant thoughts. The research carried out by Payne et al. provides evidence for a connection between sleep involving rapid eye movement and the increased ability

(2008) notes the connection between episodic memory and memory with emotional connotations, pointing out that episodic memories can be triggered by heightened emotional awareness within an individual. This seems to be counterintuitive in light of the fact that episodic memory is related to non-rapid eye movement sleep, and in turn the hippocampus (Drosopoulos et al., 2013), while emotionally significant memory relates more to rapid eye movement sleep and its effect on the amygdala (Sterpenich et al., 2013). One reason for explaining the connection between episodic memory and emotional triggers is offered by a study carried out by Prince and Abel (2013), in which they note the connection between the hippocampus and amygdala, as much of the functioning of the amygdala relates to communication from the

(2006), in which it was explained that the first four stages of sleep, which are characterized by non-rapid eye movement, have been described in some cases as continuous in nature, rather than being split into four qualitatively distinct stages. This idea has been supported electroencephalography readings that show a gradual shift in brain activity, and it is relevant in looking at a concept like slow wave sleep (Drosopoulos et al. 2005). If the stages of the sleep cycle are more similar to each other than previously thought, the notion that slow wave sleep only occurs in certain stages of the non-rapid eye movement portion of the sleep cycle becomes questionable (Prince & Abel, 2013). In light of these issues, it is clear that future research is needed to concretely define the differences between the stages of sleep, as there are noticeable discrepancies between the studies of different researchers. A better understanding is needed not just of the nature of the different sleep stages, but it must be determined whether or not all five stages can be viewed as categorically separate from one