Short-term; Long-term memory and learning Flashcards
What three different types of short-term memories are discussed in neuroscience and what are their characteristics?
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Echoic/Sensory/Iconic memory
* Ultrahigh capacity
* Rapid decay (ms)
* passive (active maintainance is not possible) -
Short term memory
* Low capacity
* rapid decay (s)
* active maintainance in theory unlimited
* sensitive to inference -
Working memory
* Short term memory with additional shielding to inference
* potential modulary architecture
* active transformation of contents
What is an oculomotor delayed task and what is it used for?
In the oculomotor delayed task, mostly non-human participants must fixate on a cross (F). After a presentation of a peripheral cue (C), they must remember the location of such peripheral cue, whilst maintaining their fixation on the cross. After a delay period (D) the participant must perform a saccade to the remembered location of the cue (C).
By doing so the information C must be upheld during D. This allows scientists to study processes underlying the active maintenance of location information in working memory.
How is the precision of saccades in the oculomotor delayed task linked to the length of the delay period?
The longer the delayed period, the longer the information must be upheld during the delay and the more inaccurate the response saccade becomes overtime. If there is a visually guided task (D=0) the variance of saccades is lowest.
What region of the brain is mostly researched in cell measurements with the oculomotor delayed task and what findings did researchers deduct from such experiments?
In Macaque monkeys, the dorsolateral prefrontal cortex (DLPFC) was researched in the late 80s. Researchers have found that there are cells that react primarily to a certain region of the visual field (in this case at 275 degrees) and do so during the delay period.
From these findings, it was hypothesized that the DLPFC contained cells that represented the encoding and maintenance of specific information in working memory.
There were however also cue related and response related response patterns in such DLPFC cells.
How do modern iterations of Oculomotor delayed tasks (ODT) challenge older findings on the location of the working memory?
In a more modern study by Christophel, Hebart & Haynes participants should perform an ODT. By using multivariate pattern analysis they could show that sensory regions and parietal regions had the most amount of predictive information on contents of the working- and short-term memory, effects in the frontal cortex however could not be demonstrated.
Does the long-term memory (LTM) have a rather large or small capacity?
The LTM has a very large capacity. A study could demonstrate, that after 2 days participants were able to recall whether they have seen an image before in a set of 10.000 images that were shown before.
What are the types and subtypes of long-term memory
Declarative: episodic, semantic
Non-declarative: procedural, classical conditioning, non associative learning, perceptual representation system
What are the two types of long-term memory?
Declarative and non declarative LTM
What are the 4 central processes/module of the Atkinson&Shiffrin extended model of memory?
Encoding
Consolidation
Short term storage
Retrieval
What does Ribot’s law express?
Ribot’s Law is a principle in the field of amnesia research that describes the relationship between the duration of amnesia and the temporal gradient of retrograde amnesia:
There is a time gradient in amnesia so more recent memories are more vulnerable to inference (loss) than older memories.
Give an example of Ribot’s law and the fragility of the consolidation process.
In a study with football players, that had a concussion it could be shown that they remembered details of the accident immediately after it happened but not 20 minutes later!
What procedure was performed on the famous patient H.M.
A bilateral medial temporal lobe resection resulted in a 5cm loss of the medial temporal lobes and large parts of the hippocampus. The rest of the Hippocampus also atrophied, possibly due to poor innervation and connectivity to other structures.
Wich immediate symptoms did H.M. carry away from his operation?
Low memory quotient
Low performance on the Wechsler verbal paired test
(Near) normal IQ
Normal perception
Normal short-term memory (if not interrupted)
Normal skill learning and normal priming abilities
Anterograde amnesia of declarative long-term memory
(minor) Retrograde amnesia of declarative long term memory (2 years before the surgery)
Which conclusion can one make from H.M. symptoms?
The hippocampus mustn’t be the hard drive/location of long-term memory
The hippocampus also cannot be the location of short-term memory, as H.M. could count and actively uphold information for short periods of time
The hippocampus consequently must be a structure that is important to consolidation of STM into LTM
What (large-scale) brain regions are involved in memory consolidation and long-term memory, and how do they interact to achieve such tasks as the storage of long-term memories?
There are three stages to explaining this model of memory consolidation:
Encoding, consolidation, and retrieval.
First during encoding sensory input is encoded in sensory systems and the hippocampus essentially points towards these sensory systems in the cortex.
During consolidation, the repeated presentation of an input results in strengthening the representation on the cortical level. This means that the connectivity between cortical regions representing an input is enforced. Over time the memory is “transferred” to these connections in the cortex until the memory representation is fully independent of the hippocampus.
At retrieval, a retrieval cue either accesses the hippocampus as a pointer to the cortical representations or directly accesses the cortical associations.
This could be evidence for a fragile hippocampus dependent state.
