The Neurology of Memory & Anterograde and Retrograde Amnesia
Introduction
Memory is defined as “the mental capacity to encode, store, and retrieve information” (American Psychological Association, 2002). It is a part of the means by which humans function. The process of forming and recalling memories involves various complex neurological processes and disruptions to these processes can result in loss of memory or the inability to form new memories. Amnesia is a memory disorder, in which, due to trauma or a head injury, certain parts of the memory is inaccessible. The two main types of amnesia are anterograde amnesia and retrograde amnesia. Anterograde amnesia refers to the inability to create new memories (Mastin, 2010). “Retrograde amnesia refers to loss of memory for information acquired before the onset of amnesia” (Squire & Alvarez, 1995, p. 169).
The aim of this report is to explore the neurology of memory, and the processes of encoding, consolidation, storage and retrieval as well as briefly investigate the two main types amnesia, anterograde and retrograde amnesia.
Neurons and Memory
The average brain has around a 100 billion electrically excitable neurons and these are the cells involved in the encoding, consolidation, storage and retrieval of memory (Mastin, 2010). Neurons use electro-chemical signals to process and transmit information. Neurons maintain voltage gradients across their membranes, driven by differences of ion concentrations of sodium, potassium, chloride and calcium within the cell, which each contain different charges (Mastin, 2010). An electrochemical impulse called an action potential is generated when this voltage gradient changes significantly (Mastin, 2010). This pulse travels quickly along th...
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Hippocampus is a small, curved region, which exists in both hemispheres of the brain and plays a vital role in emotions, learning and acquisition of new information. It also contributes majorly to long term memory, which is permanent information stored in the brain. Although long term memory is the last information that can be forgotten, its impairment has become very common nowadays. The dysfunction is exemplified by many neurological disorders such as amnesia. There are two types of amnesia, anterograde and retrograde. Anterograde amnesia is inability in forming new information, while retrograde refers to the loss of the past memory. As suggested by Cipolotti and Bird (2006), hippocampus’s lesions are responsible for both types of amnesia. According to multiple trace theory, the author suggests that hippocampal region plays a major role in effective retrieving of episodic memory (Cipolotti and Bird, 2006). For example, patients with hippocampal damage show extensively ungraded retrograde amnesia (Cipolotti and Bird, 2006). They have a difficult time in retrieving information from their non-personal episodic events and autobiographical memory. However, this theory conflicts with standard model of consolidation. The difference between these theories suggests that researchers need to do more work to solve this controversy. Besides retrieving information, hippocampus is also important in obtaining new semantic information, as well as familiarity and recollection (Cipolotti and Bird, 2006). For instance, hippocampal amnesic patient V.C shows in ability to acquire new semantic knowledge such as vocabularies and factual concepts (Cipolotti and Bird, 2006). He is also unable to recognize and recall even...
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On a scale from one to ten, I give this movie a seven. This film was well written and directed; the he plot was confusing at first, once I figured out that Christopher Nolan was trying to do, the rest of the story line was fairly easy to follow.
Understanding the reasoning behind amnesia and the hippocampus is of critical importance in neuroscience. Discussed by Cipolotti & Bird (2006), LTM impairments can lead to anterograde and retrograde amnesia if the medial temporal lobe (MTL) is damaged bilaterally. Specifically, the two most important types of LTM related to anterograde and retrograde amnesia are episodic and semantic memories. Conversely, many researchers have long debated the true functions of the hippocampus and have allowed two theories to emerge. The standard model of consolidation (SMC) assumes that the hippocampus is important in consolidating LTM, while the multiple trace theory (MTT) argues that information is encoded by specific memory traces by the hippocampus. These two theories help further explain the vast functions of the hippocampus. However, in regards to amnesic patients, the SMC has proven to be more widely accepted due to reported results implying that the hippocampus is important in consolidating LTM. In contrast, in anterograde patients, memories can be retrieved through recollection and familiarity. In fact, it has been proposed that the recol...
Therefore, they summarize that the reason why Clive suffers in the Amnesia is caused by the hippocampus is not affected. The Hippocampus is a structure that is located inside the temporal lobe, and that is a part of the limbic system. The function of the Hippocampus is similar to a post office used for encoding, storage and recalling memories, all presenting information would first remain, analysed and encoded in the Hippocampus then transmit them to different areas of the brain. In other words, Clive is unable to encode memory and hold information which is currently aware, and it is difficult to form new long-term memory such as explicit and semantic memory. Clive Wearing, now 78 years old, still cannot recover from the anterograde amnesia, he becomes a man who has the shortest memory in the world.
It is also known as dissociative amnesia. It is a disorder that happens after a traumatic event. The person going through this type of amnesia is blocking the painful event out of their heads. The person with this disorder goes through severe depression and has a sudden loss of whom they are or where they are, lasting for a few hours to a few days. They are able to form new memories.
Amnesia, a severe long-term memory loss disease, is caused by damaged brain tissue. There are two different types of amnesia. Retrograde amnesia is also known as backward moving. This is when you have a hard time remembering the past, especially episodic memories. This occurs because of memory consolidation. Memory consolidation is the process of a new memory setting until it becomes permanently in the brain. If this process is disrupted, the memory may be lost (Hockenberry and Hockenberry page 265). Anterograde amnesia is also known as forward moving. This is when you are unable to form new
Anterograde Amnesia (AA) is commonly known as short term memory loss. It is the inability to form any new memories after a neurological or psychological trauma in the brain. “Current definitions of anterograde amnesia emphasize the presence of severe and permanent deficits for the recall of recent events (typically with poor recognition) that contrast with intact short-term memory, IQ, semantic memory, skill learning, simple classical conditioning, perceptual learning, and priming” (Aggleton, 2008, p. 1442). Also, according to Aggleton, AA causes the inability to recall autobiographical events (episodic memory). Research shows that damage to the diencephalon or frontal lobe can cause AA. Damage to the diencephalon impairs memory performance because it encodes new experiences for future recall and damage to the frontal lobe of the brain weaken memory performance because the it is involved in regulates access explicit memory (Mendev 2007). Duff, Wszalek, Tranel & Cohen (2008) stated...
Another point is that working with humans and monkeys has led to the idea that the severity of memory weakens grow up as more components of the medial temporal lobe memory system are damaged. This idea has been strengthen by oversized number of individual cases in monkeys where performance on memory duties by groups of monkeys with different damage to the medial temporal lobe has been compared. Primarily, these aborts began with large mutual wound of the medial temporal lobe that approximated the damage sustained by the well-studied amnesic patient. This wound includes the hippocampal type, the amygdala, and the surrounding perirhinal and parahippocampal cortices. This wound and others in the same parts that removed fewer waves, produced again in many important features of the memory weaken in specific patient.
Making and storing memories is a complex process involving many regions of the brain. (3). Most experts agree that we have two stages of memories - short-term memory and long-term memory. Short-term memory is the immediate memory we have when we first hear or perceive someth...
Memory encompasses information that has been learned and stored over a period of time. Once an event is stored in our memory it can be readily retrieved. Amnesia occurs when there is partial or complete memory loss. There are two types of memory loss: anterograde amnesia and retrograde amnesia—which can be a result of either an organic cause, damage to the brain by physical injury; drug usage; mental disorders; or post-traumatic stress (Mastin).
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Additionally, an older work had been done to examine and exemplify that the amount of activity in the ventrolateral prefrontal cortex during long-term memory encoding can to a certain degree predict the possibility that the material encoded will be successfully recalled. In contrast to this, a study on long-term memory retrieval has highlighted the reliability of this presence and found evidence of this in the anterior, frontopolar prefrontal cortex. (Breweret al.,1998
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