Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Brain and Behaviour 2 > Brain Systems For Memory > Flashcards

Brain Systems For Memory Flashcards

1
Q

Why is memory important?

A
  • Learning from experience shapes thought and behaviour in an adaptive way:
    > Perception is an interaction between sensory inputs and stored knowledge
    > Attention is driven by memory
    > Memory underpins conscious and unconscious decisions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Cocktail party effect

A

The effect of meaning on auditory attention (e.g if you hear your name in a conversation, this will appear louder)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Clive Wearing (CW)

A
  • He was a conductor and musicologist who developed dense amnesia following encephalitis
  • Using his STM, he could retain about 20 seconds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Patient HM (Henry Molaison)

A
  • A neurosurgeon performed bilateral medial temporal lobectomy to treat his epilepsy. This involved removing the hippocampus in both hemispheres. This cured his epilepsy but had unexpected consequences for memory
  • Most of the anterior hippocampus and surrounding cortex was removed, plus amygdala. Some posterior hippocampus remained
  • He suffered from anterograde amnesia (could not form new memories)
  • He suffered from some retrograde amnesia (forgetting for memories 11 years before surgery, but childhood memories preserved)
  • This research suggests the hippocampus is crucial for learning new memories and storing of recently formed new memories, but not for older memories
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Other causes of amnesia:

A
  • Other causes of amnesia also produce damage to bilateral medial temporal lobes (as well as specific structures):
    1) Anoxia (e.g heart attack, CO poisoning)- hippocampus affected (e.g Patient RB following surgery)
    2) Head Injury- hippocampus, thalamus, frontal lobes affected (e.g Patient KC)
    3) Herpes Simplex Encephalitis- hippocampus, anterior temporal cortex (e.g patient CW)
    4) Korsakoff’s Syndrome- mammillary bodies
    5) Alzheimer’s Disease (AZ)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Locations of hippocampus, fornix and mammillary bodies

A

Hippocampus is located within the medial temporal lobe

Fornix is a major output of hippocampus

Mammillary bodies are a gateway from fornix to thalamus

Hippocampus > fornix > mammillary bodies > thalamus > cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Dissociable memory systems

A
  • There are distinct systems that can be studied separately:

1) Short-term memory (STM)
2) Episodic memory (LTM)
3) Semantic memory (LTM)
4) Procedural memory (LTM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Patient EP

A
  • Amnesia following herpes simplex encephalitis. This virus spread from face along cranial or olfactory nerves to the brain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which aspects of memory are preserved or impaired in amnesia

A

Impaired:
- Memory for verbal stimuli
- Memory for visual stimuli

Preserved:
- Ability to retain information in STM
- Retrieval of old information e.g childhood memories
- Motor learning, priming, and implicit memory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Impaired in amnesia: verbal learning

A
  • This is studied using paired-associate learning: participants have a study period to learn the pairs of words. There is then a 7 minute delay period. Finally, a retrieval period occurs whereby participants are presented with one of the words from the pair and have to recall the other word
  • Patients with dense amnesia do not remember studying any words so cannot attempt this task
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Impaired in amnesia: visual learning

A
  • This is studied using the Rey figure copy test: participants are shown an image. They copy the image either immediately or after a delayed period (e.g 15 minutes)
  • Participants with severe amnesia cannot attempt this
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Preserved in amnesia: STM

A
  • Patients with amnesia are only impaired when information must be retrieved after a period of not thinking about it
  • This suggests the hippocampus is not crucial for using attention to keep active (as the amnesia patients that have had it mostly removed can still use rehearsal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Preserved in amnesia: semantic information

A
  • Amnesia patients show normal performance on tests such as providing definitions, naming pictures, understanding sentences
  • This suggests the hippocampus is not the final storage for knowledge
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Preserved in amnesia: classical conditioning (Implicit information)

A
  • Claparede (1911): handshake with concealed pin; later amnesia patients refused to shake hands despite no recollection of doctor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Preserved in amnesia: motor learning (implicit learning)

A
  • Milner (1968): HM completed mirror drawing. The number of attempts per day it took to accurately replicate the image in the mirror decreased over time
  • This suggests the hippocampus is not required for some types of non-conscious learning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Preserved in amnesia: priming (implicit learning)

A
  • Graf et al (1984): highlights an important distinction in memory: the difference between explicit (conscious) and implicit (unconscious) memory processes:
  • Impaired memory: When participants are required to consciously retrieve information (explicit memory tasks), such as recalling or recognizing specific details, their memory performance may be poor.
  • Intact memory: The same participants may perform well on tasks that do not require conscious retrieval (implicit memory tasks), such as completing word stems or identifying patterns based on previously encountered information.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Declarative/explicit (conscious awareness)

A
  • Episodic memory
  • Semantic memory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Non-declarative/implicit

A
  • Procedural
  • Priming
  • Classical conditioning
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the hippocampus crucial for?

A
  • It is crucial for the conscious retrieval of an experience or episode: mental time-travel made possible by binding together different aspects of experience
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Reactivation

A
  • Place e.g parahippocampal area
  • Object e.g inferior temporal cortex
  • Familiar character e.g anterior temporal lobes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the structures that make up the hippocampus?

A

Inputs: denote gyrus
Associations: CA1 and CA3 fields
Outputs: Subiclum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 3 cortex around the hippocampus?

A
  • Entorhinal cortex: gateway between hippocampus and cortex
  • Perihinal cortex: important for object recognition
  • Parahippocampal: spatial layout coding

The hippocampus forms associations. The perihinal and parahippocampal cortex learn about familiar objects and locations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Anterior vs posterior hippocampus

A
  • Posterior: spatial memory. It receives greater input from parahippocampal cortex
  • Anterior: emotional memory, item familiarity/salience. It receives greater input from perihinal cortex and amygdala
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Research support for the different roles of the hippocampus (posterior vs anterior)

A
  • Moser et al (1993): found that spatial learning in rats was impaired by posterior hippocampus removal rather than anterior
  • Strange et al (1999): double dissociations (when a lesion to one part of the brain impairs one function, but not another and vice versa)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Memory features of the hippocampus

A
  • It receives connections from all modalities (e.g vision, sound etc). This is because memories are multi-sensory
  • Contains multiple nested feedback loops. This is ideal for associative learning
  • Neurons have special properties that support memory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Cellular mechanisms for memory: LTP (long-term potentiation)

A
  • LTM at the level of individual neurons reflects structural changes at the synapse
  • This refers to the idea that LTM are encoded and stored through structural and physical changes in the connections between neurons
  • Essentially, the brain physically remodels it’s connections between neurons to ‘store’ LTM
  • In the brain, this happens because of LTP
  • Donald Hebb (1969) explains it as ‘cells that fire together, wire together’
27
Q

Step-by-step process of LTP

A

1) Glutamate is an excitary neurotransmitte. It binds to receptors on the post-synaptic neuron, causing sodium (Na+) channels in the membrane to open. This allows for Na+ ions to flow into the post-synaptic cell, making it more positively charged
2) A certain amount of glutamate is required (a strong stimulus) to open enough channels, to allow enough Na+ ions in, to allow the post-synaptic cell to become depolarised, and therefore fire the action potential
3) A strong stimulus activates molecular changes that strengthen communication at the specific synapse that transmits the action potential:
- More glutamate receptors
- Receptors become more sensitive to glutamate
- Structural changes in the synapse e.g dendritic spikes
4) These collectively cause a stronger response in post-synaptic cell, helping encode memories and learned behaviours

28
Q

Bliss and Lono (1973): demonstrated LTP in rabbit hippocampus

A
  • Electrical pulses were applied to two different neural pathways (pathway 1 and 2). Both showed similar responses, slight depolarisation
  • Then, pathway 1 was given high-frequency stimulation (conditioning), with pathway 2 receiving no such conditioning
  • Afterwards, the pulse to pathway 1 showed greater response (larger depolarisation) than pathway 2. This showed an increase in synaptic strength
  • This suggests that synaptic connections can be strengthened through high-frequency, as a result of LTP
29
Q

Studying spatial learning in animals: Morris (1986)- water maze

A
  • Trial 1: rat searches for a way out of the maze and eventually discovers a hidden platform
  • Trial 2: the rat remembers the location of this platform. They swim there much faster, using landmarks to navigate
30
Q

Studying spatial learning in animals: Toneaga (1996)- transgenic mice

A
  • Gene-splicing was used to create a strain of knock-out mice that lack NMDA receptor in CA1. This creates an impairment of spatial learning
  • Other forms of learning such as CC are preserved. This because CA1 specialises in spatial learning memory formation
  • This suggests that LTP in CA1 field is critical for spatial memory
31
Q

What are place cells?

A

They are cells in CA1 that become active when an individual is in a particular place (familiar)

32
Q

Theories of the hippocampus

A

Theory 1: Cognitive map (O’keefe and Nodel, 1978): Hippocampus provides an internal map that codes for spatial relations between objects in the environment. Maguire (2000) supports this idea, looking at spatial memory in humans. Voxel-based morphometry (VBM) measures size of brain structures. He found that experienced taxi drivers had more voxels in posterior hippocampus (due to more spatial knowledge)

Theory 2: Relational memory: Rats with hippocampal lesions can remember individual associations but cannot infer relations. This is supported by Dusrk and Eichenbaum (1997) using a transitive inference task. Colours depict different odours on beakers. Rats can learn which beaker out of a pair is rewarded with food, but cannot infer the best beaker to choose when both beakers have been rewarded previously (need relationship framework)

Theory 3: Recollection vs familiarity: The hippocampus plays a unique role in recollection by supporting mental time travel and relational memory. Familiarity is more basic, less detailed recollection and is mostly handled by the perihinal cortex. Both types are declarative memory

33
Q

Episodic vs semantic (Tulving 1972)

A

Episodic:
- Events
- Mental time-travel
- Self-referential
- Fragile, easily forgotten
- Affected in amnesia
- Better when young

Semantic:
- Facts
- Time-place not coded
- Not self-referential
- More durable/consolidated
- Not affected in amnesia
- Better when old

34
Q

Patient KC: A striking dissociation

A
  • He developed amnesia after a motorbike accident
  • Episodic: In addition to inability to remember recent and new events, he had very pronounced retrograde amnesia- for much of his life
  • Semantic: Retained some concepts gained as a machinist
35
Q

Single vs double dissociation

A
  • A single dissociation occurs when a lesion or impairment affects one cognitive function but leaves another function relatively intact e.g has an impaired episodic memory, but intact semantic memory
  • A double dissociation requires evidence from two separate cases showing opposite patterns of impairment e.g Case 1: episodic impaired, semantic intact, Case 2: semantic impaired, episodic intact
36
Q

Semantic dementia

A
  • Difficulty understanding language and remembering names
  • Impaired memory of recent events
  • Poor understanding of words and objects
  • Impaired working memory
  • It is a subtype of frontotemporal dementia (FTD)
  • Progressive loss of conceptual knowledge across modalities
  • Relatively intact memory for recent events, but impaired semantic memory
37
Q

Two distinct systems for episodic and semantic memory

A
  • Patient KC and studies of semantic dementia provide a double dissociation between episodic and semantic memory
  • Hippocampus: encodes and recreates unique multimodal experiences of people/places/objects in events
  • Anterior temporal lobe (ATL): extraction of similarities between multimodal experiences to create concepts
38
Q

Hippocampus vs neocortex

A
  • Fast learning in hippocampus: quickly binds together the elements of episodes. Few neurons code for each item, so similar memories can be separated
  • Slower learning in neocortex : similar features shared by multiple experiences are encoded strongly. Useful for semantic category learning. This prevents catastrophic interference, which is the loss of old memories when new material is learned
39
Q

Kim and Fanselow (1992): hippocampal damage

A
  • If hippocampus is damaged one month after encoding, there still some memory loss
  • If hippocampus is damaged two weeks after learning, 50% forgetting. This is because some but not all information has been transferred out of the hippocampus
  • Recently acquired memories are more vulnerable: when the hippocampus is damaged after learning has occurred, memories are especially vulnerable if they were only recently learnt, with older memories preserved
40
Q

Temporal gradient

A
  • This suggests that memory loss is not uniform across all past experiences. Memories closer to the onset of amnesia are more at risk than distant memories from your past:
    1) Poorer episodic than semantic: episodic memories are more often affected than semantic because they are more contextually bound, so may be less consolidated over time
    2) More severe anterograde than retrograde: anterograde amnesia is typically more severe in conditions like AD of hippocampal damage because forming new memories heavily relies on these brain structures, while storing of memories does not
    3) Poorer retrograde amnesia for more recent events: recent memories are more likely to be lost. Older memories are usually better preserved because they are less dependent on vulnerable brain regions like the hippocampus
41
Q

Explaining the temporal gradient in amnesia

A
  • Older memories have been retrieved more times, which changes their quality (and neural basis); they become more story-like and reliant on semantics (Cermack and O’Connor, 1983)
  • Older memories are more reliant on neocortex and less dependent on hippocampus over time, following consolidation (Squire, 1992)
42
Q

Necessary connections for memory

A

1) Hippocampus: It is essential for forming new episodic and some semantic memories:
- Hippocampus > entrohinal cortex > neocortex (critical for encoding and consolidating LTM)
- Hippocampus > prefrontal cortex (important for retrieving memories, especially context-specific ones)
2) Amygdala: It is essential for associating emotions with memories:
- Amygdala > hippocampus (strengthens emotional memories, making them more vidid and easier to recall)
3) Neocortex: Stores consolidation memories (e.g semantic memories)

43
Q

Sleep plays an active role in memory consolidation

A
  • Sleep is thought to play an active role in stabilising memories
  • Slow-wave sleep (SWS) is important for declarative memory consolidation
  • Marshall et al (2006): electrical stimulation that enhances SW rhythm boosts verbal learning
44
Q

Friedrich et al (2014): sleep helps babies generalise word meaning

A
  • Babies aged 9-18 months who napped for 1.5 hours were better at generalising meaning beyond the exemplar that was learned (compared with babies who stayed awake)
  • Correlated with sleep-based electrical activity (‘sleep spindles’)
45
Q

Wilson and NcNaughton (1994): reactivation during sleep in rats

A
  • Neurons that code for routes through a maze were reactivated during sleep in that order during SwS
46
Q

Diekelmann et al (2011): reactivation during sleep in humans

A
  • Participants were trained on a card-pairing task where they had to remember the location of card pairs. During this learning, an odour was presented alongside to associate it with the memory task
  • After learning, participant wither took a nap or stayed awake. For those who took a nap, the same odour was reintroduced during SWS to serve as a memory cue
  • They found that the participants who were exposed to the odour during SWS showed better recall of card locations. Those who were presented with the odour during wakefulness or during REM sleep did not significantly improve memory performance
  • This study suggests that the odour cue helped reactivate the associated memory traces during SWS, facilitating their consolidation to LTM
47
Q

Multiple Trace Theory (Nadel and Moscovitch, 1997)

A
  • Hippocampus may remain important for some old memories
  • Hippocampus re-encodes during retrieval to create multiple traces and remains important for any recollection experiences
48
Q

Developmental amnesia

A
  • Jon, Beth and Kate with bilateral hippocampal damage from birth (hypoxia due to complications in labour)
  • Amnesic: poor at verbal and non-verbal learning
  • IQ, academic attainment, reading comprehension, working memory, semantic memory all developed normally
  • In this case, they showed 44% reduction in hippocampus relative to controls
  • Entorhinal and perihinal cortex relatively unaffected in DA, potentially providing the basis for semantic learning
49
Q

Default mode network (DMN)

A
  • Key regions: angular gyrus, posterior cingulate cortex, hippocampus, medial prefrontal cortex
  • Role in memory: supports spontaneous thought and episodic recollection, showing no overlap semantic retrieval (or controlled retrieval)
50
Q

Role of ventrolateral prefrontal cortex (VLPFC)

A
  • Directs attention to critical aspects of an experience
  • VLPFC biases ongoing processing in favour of relevant representation
  • It directs attention to important aspects of experience, so is crucial for retrieving linking between objects and contexts
51
Q

Types of interference

A

Proactive interference: new memories are affected by older memories

Retroactive interference: old memories are affected by newer memories

52
Q

Interference and false memories

A
  • VLPFC supports memory accuracy by suppressing competing memories. Failure can result in false memories
  • Low VLPFC activity leads to false memories
53
Q

Badre and Wagner (2005): how interference during memory retrieval is managed

A
  • Participants were given associative memory tasks, where they learned pairs of stimuli. Some pairs shared overlapping elements, creating high-interference conditions. During recall, participants were presented with a cue and asked to recall the associative word whilst fMRI monitored activity
  • They found the left VLPFC showed increased activity during high-interference trials, suggesting it plays a role in suppressing irrelevant, competing information
  • In high-interference conditions, retrieval success depended on the strength of cognitive mechanisms
54
Q

Retrieval failure following damage to PFC

A
  • Poorer recall than recognition and strong effects of cueing
  • Poor source memory- problems discriminating between similar memories
  • Unhelpful information is retrieved (false memories)
55
Q

Confabulation

A
  • Involves recalling implausible events
  • Linked to failure in meta-cognitive processes mediated by the PFC
56
Q

Korsakoff’s syndrome

A
  • Amnesia associated with long-term alcoholism
  • Caused by thiamine deficiency, as alcohol reduces absorption and storage of vitamins, as well as interfering with the conversion of thiamine into active form
  • It causes damage to the brain: mammillary bodies and PFC
  • Symptoms: behavioural change, confabulation, retrieval issues despite cues present
57
Q

Varieties of semantic impairment

A

Patients fail the same range of verbal and non-verbal semantic tests, but for different reasons:
- Semantic dementia (SD): progressive breakdown of knowledge from specific to general information (degradation of amodal semantic representations)
- Semantic aphasia (SA): retrieval dominated by strong associations, even when these aren’t relevant (deregulated semantic retrieval)
- Patients with lesions of VLPFC have false memories and associations due to the absence of the ability to resolve competition between memory stores

58
Q

Two retrieval networks

A
  • Default mode network (DMN): retrieval from strong cues
  • Controlled memory retrieval (CMN): resolving competition, retrieving weak targets
59
Q

Forgetting (old vs new outlook)

A
  • Traditionally thought of as bad and a consequence of trace decay/interference
  • New outlook: forgetting arises from need to control competition process in retrieval
60
Q

Anderson et al (1994): retrieval-induced forgetting

A
  • Investigated how the act of retrieving certain memories can impair the retrieval of related but unpracticed information (retrieval-induced forgetting)
  • Participants were presented with category-exemplar pairs (e.g fruit-orange, fruit-banana, animal-tiger, animal-elephant), then practiced retrieving some of these pairs but not others. Finally they were asked to recall all the exemplars, including both practiced and unpracticed
  • They found that participant showed reduced recall for the unpracticed related items compared to unpracticed unrelated items. This supports the idea of retrieval-induced forgetting
  • Repeated retrieval of an item reduced the activation of VLPFC (as the task is easier, so reduced chance of interference)
61
Q

Can we internationally forget?

A
  • Freud: repression
  • Suppression: conscious process, goal driven/intentional and related to executive control
62
Q

Inhibitory control (behavioural vs cognitive control)

A
  • Behavioural control: the ability to control actions based on goals. The Go/No-Go Task measures inhibitory control over action (press a button when letter appears, but don’t press button if another letter appears)
  • Cognitive control: the ability to flexibly control thoughts in accordance with goals, and stop unwanted thoughts from entering consciousness. Think/No-Think Task measures inhibitory control over memory
63
Q

Anderson and Green (2001): Think/No-Think paradigm

A
  • Participants were shown pairs of cue words and target words. They were then presented with the cue word and instructed to either think about the associated target word or suppress the memory of it
  • After multiple trials of this, participants were tested on their ability to remember the target words
  • They found that the participants showed impaired recall for the No-Think items. This suggests that the act of trying to suppress a memory led to its later suppression or forgetting
  • This suggests that brain can actively inhibit the retrieval of certain memories in a controlled way
64
Q

Traumatic events

A
  • These can lead to vivid and intrusive memories
  • PTSD: trauma results in persistent anxiety often accompanied by flashbacks. Development of PTSD following trauma could be linked to difficulty in using PFC to suppress emotive memories

Brain and Behaviour 2 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions