Introduction and Neurobiology of Memory Flashcards
Describe an old basic model of memory
Learning => Storage of information || <= Consolidation || <= Generalisation (Retention) || <= Distortion || <= Forgetting \ / Retrieval based on cue <= Remembering (or not!)
Just look at docs lol
Describe three ways to boost learning ability in study
Divide time over (spacing effect)
Make sure you can reproduce the information (generation effect, retrieval practice effect and levels of processing effect)
No alcohol during learning (state-dependent learning) unless you drink for the exam too (recommended)
How did Aristotle contribute to memory?
Associations between stimuli
Important philosophical thought in 17th and 18th Century (mainly British: John Locke, John Stuart Mill)
What did the book ‘Rhetorica as Herennium’ contribute to memory?
Method of Loci (along a pathway)
How did Darwin contribute to memory?
The evolutionary importance of responding to the environment
Our memory is no different- evolved so that we as humans can function optimally in our own environment, other animals have evolved different memories for their environment. (honeybee only has 100,000 neurons but is enough to go find food, come back to the hive and communicate that- intermediate memory.)
What feature of memory does the existence of the intermediate memory in the bee demonstrate?
The memory (eg a flower path) disappears after 2/ 3 days
People with certain conditions demonstrate that we have the capacity to remember much more than we do- suggesting that there are mechanisms for discarding unnecessary information?
Who is the founder of modern memory psychology?
Hermann Ebbinghaus
What did Adolf Jost contribute to memory research in 1987?
Jost’s Law: If two memory traces have equal retrieval probability, but different ages, the older one will–
(a) be forgotten more slowly than the younger one–
(b) benefit more from additional learning
What did Sir Francis Bartlett contribute to memory research?
More about the structure (construction) of memory (schemata, gestalt psychology),
What did William James contribute to memory research? (3)
–One of the founders of psychology
–Distinguish primary and secondary memory
–Tip-of-the-tongue phenomenon
What did Freud contribute to memory research? (3)
–Emphasis on unconscious processes
–Repression as a mechanism for forgetting (influence of emotion)
–Slip-of-the-tongue phenomenon
How did Lasley contribute to memory in 1925?
One of the first in neurobiology
Had mice find cheese in a maze, cut out a piece of cortex and see if he could still find the cheese. Eventually he found that if he cut out a lil cortex barely any effect, if he cut out larger pieces, they would get gradually worse to the same degree.
He concluded that memories are spread across the mouse cortex and localisation is not applicable.
How did Theodule Ribot contribute to memory research (2)?
–Neuropsychology of memory
–Ribot gradient ( if you get damage from an accident or disease, its the newer memories which suffer, rather than the older memories)
How did Donald O. Hebb contribute to memory research? (2)
- Hebbian learning (neural networks, before they had been discovered)
- “Cells that fire together wire together“
What influenced cognitive psychology? (3)
–Emerging computer science in the 1940s
–Shannon and Weaver’s “A Mathematical Theory of Communication” (Shannon popularised the concept of ‘bit’)
–Computer memory:
•RAM vs. Hard-disk = STM vs. LTM
How is memory viewed under cognitive psychology?
Memory now viewed as carrier of information that is manipulated during cognition
What did Miller claim about memory in 1956?
Miller’s law- The magical number 7 ± 2 (WM)
What did Broadbent contribute to memory?
Broadbent’s (1958) Information model
What other model of memory was produced under cognitive psychology?
Sensory store- all information in lost in 1/2 to 3 seconds
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If paid attention
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Short term or working memory store (up to three ‘chunks’)- Unrehearsed information is lost in 10 to 15 seconds
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Encoding/ Retrieval
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Long-term store (Some information may be lost over time)
Describe the Bradley and Hitch Model (1974)
Central executive, Longterm memory, episodic buff, visuospatial sketchpad, phonological loop
look at copy
How did Tulving contribute to memory?
Episodic memory- temporal events in subjective time
Semantic memory- general knowledge (No event structure)
Procedural- operations involved in executing task, knowing how, stimuli and response memory
What aspect of fear conditioning was shown during the lil Albert study?
Generalisations- stuff that had the same qualities as the thing he feared (fur coat)
What did Penfield find through neural stimulation and why was he doing this?
He would stimulate different areas of the cortex and ask subjects what they experienced in an attempt to avoid certain areas during split brain surgery.
He found that certain areas produced very specific sensations, movements, smells or auditory or visual hallucinations. Gives evidences for localisation and localised memory.
How may the threshold vary between neurons for an action potential?
Some are standard- when enough to hit -55mV, however some only when they get two lil spikes a certain temporal distance apart (e.g 2 ms), some on the first stimulus they start spiking and on the second stimulus they stop spiking. There are many different spiking patterns
Explain long term potentiation (LPT)
If a neuron in repeatedly stimulated, then the number of vesicles and receptors will increase over time, increasing their communication capacity and intensity.
Describe (Hebbian) learning in the brain
A dendrite can form a connection (synapse) with an axon through new experiences or learning. Prolonged experience or training can strengthen that connection (both ‘spine’ and axon will become bigger). The connection can be weakened when the experience is removed and strengthen again through repeated experience or relearning.
This changes constantly, over the course of minutes you see the development and withdrawal of spines ( as demonstrated by neural dynamics with two photon microscopy in the living mouse.) Appears to almost be the case that these changes are mostly random and not motivated by changes or stimuli. Seems to be a ‘search’ process going on where spines search for something to connect to and even if they make a good connection, they may decide to become smaller seemingly randomly. They fluctuate like crazy.
What may larger spines represent?
They change a lot less and less frequently than smaller spines, so may represent older, more secure memories.
What brain regions is the declarative (explicit) memory (both facts and events) associated with?
Medial temporal lobe (hippocampus/ perirhinal cortex/ hippocampus para)
Neocortex
Name four types of memory under non declarative memory?
Procedural (skills and habits)
Priming
Simple classic conditioning
nonassociative learning
What brain area is associated with Procedural (skills and habits) memory?
Striatum
What brain area is associated with priming?
neocortex
What brain areas are associated with simple classical conditioning? (2)
Cerebellum (timing),
amygdala
What brain area is associated with nonassociative learning?
reflex pathways
What did John O’keefe discover about hippocampus function in 1971?
He showed that place cells in the brain (hippocampus) signal position and provide spatial memory capacity- Electrodes in the rats brain signal measure where cells fire as it runs around an enclosed area. These ‘place cells’ activate only when the rat is in a particular location in the area.
How did May-britt Moser and Edvard Moser add to O’keefes research on the place cells in the hippocampus in 2005?
They demonstrated that, in a neighbouring part of the brain, grid cells provide an internal coordinate system for navigation. Grid cells fire when the rat passes certain locations, forming a hexagonal grid.
What did the Morris Water Maze demonstrate?
He placed rats at different starting points of a circular water bath. The rat had to find an underwater platform on which he could stand to breath. The water would be milky white to make it hard to find. It was not too difficult or stressful as it mimicked similar situations in the wild.
Normal rats would almost swim directly to the spot after a few repeated trials. Rats with a hippocampus lesion they don’t learn to find the platform unless they have a constant starting position, then they will eventually learn it (albeit at a slower rate).
This is also true for humans with similar lesions or symptoms; cannot form new memories but can learn to play the piano or something
What old idea was formed from Morris’ studies and what alternative idea is given?
Old idea: The hippocampus is specialised in spatial memory
Alternative idea: Hippocampus plays a role in remembering complex associations
What other area is involved in the formation of these complex associations?
Parahippocampal areas - essential for the formation of complex associations
Describe a study which demonstrated the role of the parahippocampal region in these tasks
The delayed non-matching to sample task
Monkey is placed in front of two food ‘wells’ (E.g circle and square). One of them has a treat and the other doesn’t. First they are shown that the circle has the treat and then they researchers consistently hide the treat under the square or showed it under the square and hid it under the circle. This makes it more complex than simply reaching for the circle.
Name the two para hippocampal areas
Parahippocampal cortex Perirhinal cortex (object of intense study atm)
Both involved in making complex associations, see diagram in notes
What other type of memory is the (para) hippocampus involved in?
episodic memory
How is this episodic memory role of the (para) hippocampus different to that of the perihinal cortex?
Its more to do with recognition: ‘feeling of familiarity’ or confidence in your recognition of something
Describe a early model which describes the role of the hippocampus during memory consolidation
(probably needs to be implemented with new consolidation mechanisms)
This model concerns the scale of about 6 weeks in humans.
The hippocampus act as a link system, mainly involved in linking parts of cortex by carrying out synaptic strengthening (higher communication between areas). This happens on a daily basis (ie going to a party and meeting new people) and causes changes and new connections in the hippocampus.
The basal forebrain area sitting below the cortex contains a lot of nuclei that transmit/ spread a lot of neuromodulators to the rest of the cortex (eg acetylcholine) and these act as a modulatory system for the synaptic changes in the hippocampus. If it does not work then the plasticity of synapses does not work and learning does not occur.
What stages of consolidation does this hippocampus model demonstrate? (4)
Stage 1: firing networks of neurons
Stage 2: within seconds hippocampal neurons become involved, changes and forms new connections (e.g connecting park with squirrel). ‘long term memory’ is formed. However in around 6 weeks it may be overwritten because the hippocampus is quite small and therefore probably has a capacity. ( but bear in mind patient who doesn’t forget.)
Stage 3: Some consolidation occurs between 2 and 3. Direct connections form between these areas. This is much too long for little spines, for these connections to occur chains of intermediate neurons are involved. So when one fires, neurons in a chain subsequently fire and reach the other neuron, which is observed in the cortex.
Stage 4: These inter-cortical connections are strengthened and no longer require the hippocampus
What is very important for moving from stage two to stage three?
Sleep, probably replay going on
What is the difference between episodic and semantic memory and why make such a distinction (2)?
Episodic- experiences “remember”
Semantic- knowledge “know”
There is:
◼Semantic dementia vs Alzheimer’s dementia patients
◼Different parts of the brain involved (temporal pole may store higher-level knowledge)
How else may memory be divided in two and why make this distinction?
- Explicit memory: retrieve something from memory
- Implicit memory: (possibly) unconscious effect of behavior due to previous experiences
◼(Anterograde) amnesia patients have implicit memory but lack explicit memory
◼Different parts of the brain are involved
How is the amygdala and stress related to memory?
Activation of the amygdala enhances memory
Short-term stress strengthens the memory
Prolonged stress is detrimental to memory (can cause physical brain damage)
