A report on Long-term memory, Anterograde amnesia, Hippocampus and Episodic memory
In neurology, anterograde amnesia is a loss of the ability to create new memories after the event that caused amnesia, leading to a partial or complete inability to recall the recent past, while long-term memories from before the event remain intact.
- Anterograde amnesiaLong-term memory is commonly labelled as explicit memory (declarative), as well as episodic memory, semantic memory, autobiographical memory, and implicit memory (procedural memory).
- Long-term memoryThe hippocampus is part of the limbic system, and plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation.
- HippocampusAlong with semantic memory, it comprises the category of explicit memory, one of the two major divisions of long-term memory (the other being implicit memory).
- Episodic memoryTo a large degree, anterograde amnesia remains a mysterious ailment because the precise mechanism of storing memories is not yet well understood, although it is known that the regions of the brain involved are certain sites in the temporal cortex, especially in the hippocampus and nearby subcortical regions.
- Anterograde amnesiaPeople with extensive, bilateral hippocampal damage may experience anterograde amnesia: the inability to form and retain new memories.
- HippocampusThe formation of new episodic memories requires the medial temporal lobe, a structure that includes the hippocampus.
- Episodic memoryFor example, anterograde amnesia, from damage of the medial temporal lobe, is an impairment of declarative memory that affects both episodic and semantic memory operations.
- Episodic memoryThese are encoded by the hippocampus, entorhinal cortex, and perirhinal cortex, but consolidated and stored elsewhere.
- Long-term memoryFurthermore, the data do not explain the dichotomy that exists in the MTL memory system between episodic memory and semantic memory (described below).
- Anterograde amnesiaOver the years, three main ideas of hippocampal function have dominated the literature: response inhibition, episodic memory, and spatial cognition.
- HippocampusHis subsequent total anterograde amnesia and partial retrograde amnesia provided the first evidence for the localization of memory function, and further clarified the differences between declarative and procedural memory.
- Long-term memory4 related topics with Alpha
Explicit memory
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Explicit memory (or declarative memory) is one of the two main types of long-term human memory, the other of which is implicit memory.
Explicit memory can be divided into two categories: episodic memory, which stores specific personal experiences, and semantic memory, which stores factual information.
Although many psychologists believe that the entire brain is involved with memory, the hippocampus, and surrounding structures appear to be most important in declarative memory specifically.
Guy Pearce plays an ex-insurance investigator suffering from severe anterograde amnesia caused by a head injury.
Temporal lobe
2 linksOne of the four major lobes of the cerebral cortex in the brain of mammals.
One of the four major lobes of the cerebral cortex in the brain of mammals.
Declarative (denotative) or explicit memory is conscious memory divided into semantic memory (facts) and episodic memory (events).
Medial temporal lobe structures that are critical for long-term memory include the hippocampus, along with the surrounding hippocampal region consisting of the perirhinal, parahippocampal, and entorhinal neocortical regions.
The temporal lobe communicates with the hippocampus and plays a key role in the formation of explicit long-term memory modulated by the amygdala.
The medial temporal lobes include the hippocampi, which are essential for memory storage, therefore damage to this area can result in impairment in new memory formation leading to permanent or temporary anterograde amnesia.
Memory consolidation
1 linksCategory of processes that stabilize a memory trace after its initial acquisition.
Category of processes that stabilize a memory trace after its initial acquisition.
The second process is systems consolidation, occurring on a much larger scale in the brain, rendering hippocampus-dependent memories independent of the hippocampus over a period of weeks to years.
Systematic studies of anterograde amnesia started to emerge in the 1960s and 1970s.
Long-term memory, when discussed in the context of synaptic consolidation, is conventionally said to be memory that lasts for at least 24 hours.
Multiple trace theory (MTT) builds on the distinction between semantic memory and episodic memory and addresses perceived shortcomings of the standard model with respect to the dependency of the hippocampus.
Amnesia
1 linksDeficit in memory caused by brain damage or disease, but it can also be caused temporarily by the use of various sedatives and hypnotic drugs.
Deficit in memory caused by brain damage or disease, but it can also be caused temporarily by the use of various sedatives and hypnotic drugs.
There are two main types of amnesia: retrograde amnesia and anterograde amnesia.
Anterograde amnesia is the inability to transfer new information from the short-term store into the long-term store.
In addition, specific areas of the hippocampus (the CA1 region) are involved with memory.
Retrograde amnesia is inability to recall memories before onset of amnesia. One may be able to encode new memories after the incident. Retrograde is usually caused by head trauma or brain damage to parts of the brain besides the hippocampus. The hippocampus is responsible for encoding new memory. Episodic memory is more likely to be affected than semantic memory. The damage is usually caused by head trauma, cerebrovascular accident, stroke, tumor, hypoxia, encephalitis, or chronic alcoholism. People with retrograde amnesia are more likely to remember general knowledge rather than specifics. Recent memories are less likely to be recovered, but older memories will be easier to recall due to strengthening over time. Retrograde amnesia is usually temporary and can be treated by exposing them to memories from the loss. Another type of consolidation (process by which memories become stable in the brain) occurs over much longer periods of time/days, weeks, months and years and likely involves transfer of information from the hippocampus to more permanent storage site in the cortex. The operation of this longer-term consolidation process is seen in the retrograde amnesia of patients with hippocampal damage who can recall memories from childhood relatively normally, but are impaired when recalling experiences that occurred just a few years prior to the time they became amnesic. (Kirwan et al.,2008)In the case of LSJ, her case shows that retrograde amnesia can affect many different parts of knowledge. LSJ was not able to remember things from her child or adult life. She was not able to remember things that most people pick up in everyday life such as logos or the names of common songs.