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...
Traumatic brain injuries (TBI) account to a third (30.5%) of all injury-related deaths in the U.S. with an estimated 1.7 million individuals sustaining TBI each year (Center for Disease Control and Prevention, 2010). Classifications of brain injury (e.g., mild, moderate and severe) is mostly done using the Glasgow coma scale (GCS) which has gained broad acceptance for the assessment of the severity of brain damage (Bauer & Fritz, 2004). Recent studies suggest that almost all patients with moderate or severe TBI have a period of recovery during which they are responsive but confused. This state is commonly referred to as the post-traumatic amnesia. Post-traumatic amnesia (PTA) is defined as “a failure of continuous memory” (Artiola et al., 1980; p.377). PTA is often cited as the best method for codifying the degree, level of recovery and outcome after a closed head injury (e.g., Artieola et al., 1980; Tate, Pfaff, & Jurjevic, 2000). PTA duration is a better indicator of outcome than early injury scales such as the GCS score (Richardson et al., 2009).This analysis will examine the limitations of the general PTA assessment scale, and investigate the benefits and limitations of both retrospective and prospective methods used to measure the duration of PTA.
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...
In the article Hippocampal contributions to recollection in retrograde and anterograde amnesia the authors believed that amnesia was cause my damage to the hippocampus.
Study on memory is important in the subconscious brain functions. Patients with amnesia, and other brain injuries affecting the brain, have trouble accessing their explicit memories. With more insight into what processes are occurring in the typical mind, it may be possible to better treat amnesiac and cognitively impaired patients to improve their condition in some way. More research in this area should be conducted to further understand and support the findings in this area. Perhaps an improvement to this study may be to perform the experiment while being observed by fMRI. This would make it possible to visually observe the areas affected in four instances: deep LOP, shallow LOP, implicit memory, explicit memory. Procedures may be devised to develop methods of cognitive exercises and therapy.
Amnesia affects the memory. People diagnosed with amnesia lose memories that occur before the onset of amnesia. Amnesia affects the memory, how well you can store long term memory. If amnesia occurs, one might have trouble with long term memory in the future, or simply forget most of their past. Due to the brains plasticity, the brain can use association areas to help build memory. Amnesia commonly comes in two forms that occur together: Retrograde amnesia and Anterograde amnesia.
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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
management of real-world memory demands despite profound anterograde amnesia. Journal of Clinical & Experimental Neuropsychology, 30(8), 931-945.
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).
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...
What brain structures are associated with memory? Why is long-term potentiation so important? What kinds of memory loss occur in amnesia and
The mechanism of human memory recall is neither a parallel nor a sequential retrieval of previously learned events. Instead, it is a complex system that has elements of both sequential and parallel modalities, engaging all of the sensory faculties of the individual. On an everyday level, issues about memory and recall affect everyone. It has a bearing on ramifications from the trivial to matters of life and death. Thus, a particular student might worry about his or her ability to remember 'memorized' material, a person might worry about losing his or her mind, and, there are the more troubling issue of diseases affecting memory such as Alzheimer's disease. According to Tulving, episodic memory represents only a small part of the much larger domain of memory (Tulving, 1992, p.1). Specifically, episodic memory is the process involved in remembering past events. This paper is a review of research findings on episodic memory with specific attention to episodic memory in adults and infants.
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