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1) Posttraumatic stress disorder (PSTD) is a prolonged stress reaction to a traumatic event; it is typically characterized by recurrent thoughts and images (flashbacks), nightmares, lack of concentration, and over reactivity to environmental stimuli such as loud noise. PTSD Can be triggered by any kinds of trauma including robbery, sexual assault, hostage situations, and automobile accidents. Menare more ofte exposed to those traumas but women are almost for times as lkely to develop PTSD when they do experience trauma. People with PTSD have smaller hippocampi than controls and this appears to be a predisposing factor rather than a result of the stress, study of Vietnam veterans, with their non combat identical twins. Hippocampal reduction is often associated with childhood abuse. PTSDsymptoms are resistant to traditional drug and psychotherapy treatments, so an alternative approach xpusure therapy is used, wich allows the individual to confron anxiety-provoking stimuli in the safety of the therapist’s office. Expousure therapy is essentialy an extinction process, and fear memories are mostly resistant to extinction. During extinction, brain imaging showed connections betweenthe prefrontal cortex, and the amygfala which is a small limbic structure in each temporal lobe that is involved in emotion, specifically negative ones and sends its emotional output to the prefrontal cortex, both, the prefrontal cortex and the amygdala are important in feat conditioning and extinction. Consolidation is the process in which the brain forms a more or less permanent physicalrepresentation of a memory. Retrieval is the process of accessing those stored memories. Like for eample when a rat presses a lver to receive food, the experience is held in memory for a brief time, and it does not necessarily become a permanent memory. Memory is therefore devided in short-term memory and long-term memory. The hippocampus belongs to the limbic system and plays important roles in theconsolidation of information from short-term memory to long-term memory and spatial navigation. Presentation of words of pictures activates the formation of the hippocampus and the parahippocampar gyrus. Animal study demonstrates that the hippocampus participates in consolidation. Rats were trained in a water maza, in which thay could scape by learning the location of a submerged plataform. ratsreceived infusions into both hippocampi of a drug that blocks receptors for glutamate, therefor remporarely disabeling the hippocampi. Therefore, the tats that were given the drug at the time of testing had impaired recall in the water maze, indicating that the hippocampus has a role in etreival as well as consolidation. The prefrontal area is active during effortful attempts at retrieval whereas thehippocampus is activated during succesfull retrieval. Hippocampus stores information temporarily (short term memory) in the hippocampal formation, then over time it stores it (Long-term memory) in the cortical areas. So as memory decreases overtime from the hippocampus, it increases activity on th prefrontal, temporal and parietal cortex. Different memories are located in different cortical areas,according to where the information they are based on was processed. There are two kinds of learning, Declarative memory which involves learning that results in memories of facts, people, and events that a person can verbalize or declare like episodic memory, factual memory, autobiographical memory and spatial memory. The other kind of leaning is nondeclarative memory which involves memories forbehaviors, therese memories result from procedural or skills learning, emotional leating and stimulus-response conditioning. The amygdala strengthens declarative memories about emotional events by increasing its activity in the hippocamps. Working memory provides a temporary “register for information whie it is being used. Prefrontal cortex serve as a temporary register for working memory. PTSD...