Patients exposed to physically or emotionally traumatic events and are at a higher risk for developing psychogenic amnesia because they seem to damage the neurons in toto in the brain. By performing a positron emission tomography activation study on psychogenic amnesic patients with face recognition, it was found that activation of the right anterior medial temporal region including the amygdala was increased in the patient whereas bilateral hippocampal regions increased only in the control subjects, demonstrating again that limbic and limbic-cortical functions are related to the symptoms of psychogenic amnesia. Tests using functional magnetic resonance imaging suggest that patients with psychogenic amnesia are unable to retrieve emotional memories normally during the amnesic period, suggesting that changes in the limbic functions are related to the symptoms of psychogenic amnesia. Psychogenic amnesia is defined by the lack of structural damage to the brain, but upon functional imaging, an abnormal brain activity can be seen. Some characteristics that define organic amnesia is the maintenance of personal identity, basic semantic knowledge and procedural skills as well as neuroradiological images showing cerebral damage to the cortical and/or subcortical areas known to be associated with long-term memory while some characteristics that define psychogenic amnesia is the loss of personal identity, semantic knowledge, and procedural abilities at least in the early phase of amnesia as well as damage directly affecting cerebral areas critical for memory functioning that cannot be detected in clinical history or neuroradiological exams. Psychogenic and organic amnesiaĬlinically, psychogenic amnesia is characterized by the loss of the ability to retrieve stored memory without having damages to the brain while organic amnesia is characterized by damages to the medial or anterior temporal and/or prefrontal regions caused by stroke, traumatic brain injury, ischemia, and encephalitis. Researchers have found that emotional memories can be suppressed via two time-differentiated neural mechanisms. Additionally, hippocampal region is known to be linked to recognizing faces. Functional imaging of normal patients reveal that right-hemisperic amygdala and ventral prefrontal regions are activated when they were retrieving autobiographical information and events. These stored episodic and semantic memories can be obtained by triggering the uncinate fascicle that interconnects the regions of the temporofrontal junction area.Įmotion seems to play an important role in memory processing in structures like the cingulated gyrus, the septal nuclei, and the amygdale that is primarily involved in emotional memories. Majority of consolidated information gets stored in the cerebral cortical networks where the limbic system record episodic-autobiographical events. According to the type of information given, the duration of consolidating stage varies drastically. During encoding, the limbic system is responsible for bottlenecking or filtering information obtained from the PNS. The information obtained from the peripheral nervous system (PNS) is processed in four stages - encoding, consolidating, storage, and retrieval. Ultra-short-term memory lasts up to hundreds of milliseconds and short-term memory lasts from seconds to minutes while anything else longer than short-term memory is considered to be a long-term memory. There are three types of memory – ultra-short-term, short-term, and long-term memory. Dissociative amnesia is due to psychological rather than physiological causes and can sometimes be helped by therapy. Situation-specific amnesia is a type of dissociative amnesia occurs as a result of a severely stressful event, as in post-traumatic stress disorder. Fugue state is very rare, and usually resolves over time, often helped by therapy. This is preceded by severe stress and/or depressed mood. Global amnesia, also known as fugue state, refers to a sudden loss of personal identity that lasts a few hours to days. There are two types of psychogenic amnesia, global and situation-specific. Other times, there may be a loss of basic semantic knowledge and procedural skills such as reading and writing. In most cases, patients lose their autobiographical memory and personal identity even though they are able to learn new information and perform everyday functions normally. It is defined by the presence of retrograde amnesia or the inability to retrieve stored memories and events leading up to the onset of amnesia and an absence of anterograde amnesia or the inability to form new long term memories. Psychogenic amnesia, also known as functional or dissociative amnesia, is a disorder characterized by abnormal memory functioning in the absence of structural brain damage or a known neurobiological cause severe cases are very rare.
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