twelve slides accompanied by a narrative. The slides varied in the degree to which they evoked emotion – slides 1 through 4 and slides 9 through 12 contain non-emotional content. Slides 5 through 8 contain emotional material, and the seventh slide contained the most emotionally arousing image and description (a picture of surgically repaired legs of a car crash victim). The emotionally arousing slide (slide 7) was remembered no better by the bilateral damage participants than any of the other slides. All other participants notably remembered the seventh slide the best and in most detail out of all the other slides. This shows that the amygdala is necessary to facilitate encoding of declarative knowledge regarding emotionally arousing stimuli, but is not required for encoding knowledge of emotionally neutral stimuli. Factors that affect declarative memory Stress Stress may have an effect on the recall of declarative memories. Lupien, et al. completed a study that had 3 phases for participants to take part in. Phase 1 involved memorizing a series of words, phase 2 entailed either a stressful (public speaking) or non-stressful situation (an attention task), and phase 3 required participants to recall the words they learned in phase 1. There were signs of decreased declarative memory performance in the participants that had to complete the stressful situation after learning the words. Recall performance after the stressful situation was found to be worse overall than after the non-stressful situation. It was also found that performance differed based on whether the participant responded to the stressful situation with an increase in measured levels of salivary cortisol. Posttraumatic stress disorder (PTSD) emerges after exposure to a traumatic event eliciting fear, horror or helplessness that involves bodily injury, the threat of injury, or death to one's self or another person. The chronic stress in PTSD contributes to an observed decrease in hippocampal volume and declarative memory deficits. Stress can alter memory functions, reward, immune function, metabolism and susceptibility to different diseases. Disease risk is particularly pertinent to mental illnesses, whereby chronic or severe stress remains a common risk factor for several mental illnesses. One system suggests there are five types of stress labeled acute time-limited stressors, brief naturalistic stressors, stressful event sequences, chronic stressors, and distant stressors. An acute time-limited stressor involves a short-term challenge, while a brief natural stressor involves an event that is normal but nevertheless challenging. A stressful event sequence is a