Neural Concepts and Representation Flashcards
2 types of declarative (explicit) memory?
Semantic (facts)
Episodic (events)
4 types of implicit / non-declarative memory?
Priming
Procedural (IQ)
Conditioning
Non - associative (habituation)
What is semantic memory?
Database of conceptual knowledge, what ‘things’ are, their properties, their name, etc.
E.g. cat = 4 legged furry animal, meows.
Shared between us all so that we can communicate – we may not have exactly the same mental image of a cat, but we all know it’s specific features, so allows us to get the mental picture.
Conceptual knowledge is highly shared amongst people and sometimes it has strong cultural links
Conceptual knowledge is part of which type of memory?
Semantic
______ knowledge is highly shared amongst people and sometimes it has strong cultural links
Conceptual
2 types of Conceptual (semantic) mental representation?
Analogical
Symbolic
What is analogical representation?
Picture-like, cartoonish, resembles the object.
(Kosslyn et al 1978) - Analogical conceptual knowledge
Resemblance: _____ layout and _____scanning
Mental images maintain ______ (picture-like)
Spatial layout and mental scanning.
Metrical distances
What is symbolic representation?
A symbol for an object.
Eg. these 3 letters: CAT - doesn’t look like the object but we know what we are referencing.
Which is the more flexible type of semantic (conceptual) memory: symbolic or analogical representation?
Symbolic.
Symbols are more flexible, we can link any idea to them
Gains (2004) asked what is the degree of overlap in the brain when we perceive something visually compared to when we imagine it?
Ss visualized or saw faint drawings of simple objects and judged specific aspects of stimuli
Draw on most of the same mental machinery, however not _________ between pictures. More overlap in _______ and ______ regions (_____ control) than in temporal and occipital.
The two domains engage sensory processes differently (occipital cortex much stronger in visual perception and no additional temporal activation in imagery)
Draw on most of the same mental machinery, however not complete overlap between pictures
More overlap in frontal and parietal regions (executive control) than in temporal and occipital
The two domains engage sensory processes differently (occipital cortex much stronger in visual perception and no additional temporal activation in imagery)
In mental representation, what are categories?
Categories can be thought of as the external content related to the concept. A collection of instances thought of as the same thing.
E.g. Boat, train, car, plane belong to the category modes of transport
In mental representation, what are concepts?
Concepts are the mental content of some object or event. All the knowledge we have about that category.
E.g Modes of transport have engines, are arodynamic, have doors, etc
Without categories we’d have to treat each new instance as if it were one of a kind. Studying categories and concepts has informed us about the _____ structure of ____knowledge (i.e. the mental image of what things are and their properties)
Internal structure of semantic knowledge.
Ross & Murphy devised the sorting task to address what problem?
What defines a category?
Which task revealed that categories are culturally influenced
E.g.
Eggs with milk and butter: dairy food
Eggs with bacon and cereals: breakfast food
The sorting task (Ross and Murphy)
What are important to define categories accruing to Barsalou?
Goals and purposes
What are the basic units of semantic memory?
Concepts
What is the mental lexicon?
Mental lexicon: single words and their meaning (cluster of properties, features)
What are semantic association networks useful for?
4 things
Semantic association networks: useful for remembering, guiding behaviour, reasoning and problem solving
What is the semantic association network?
A knowledge base that represents semantic relations between concepts in a network. This is often used as a form of knowledge representation.
What are the names of the 2 theories of categories?
Classical view & Prototype model
The classical view of categories asserts that the possession of common properties (a set of features) is ____ and _____ to be a member of a category.
Necessary: each feature must be present
Sufficient: If each feature is present that’s all you need
The classical view of categories entails that every member of a category possesses the same ______ and is _____ representative of that category.
Possesses the same characteristics and is equally representative of that category.
The following statement is an example of which theory of categorical mental representation?
To be a member of the category “triangle” the object must possess the features: closed figure with three sides
Classical View
The ‘typicality effect’ is a criticism of which theory of categorical mental representation?
Classical View
What is the typicality effect?
What does it suggest the classical view should adapt to explain?
Some members are ‘more members’ than others.
Slower reaction times when making a category judgment for “penguin is a bird” compared to “robin is a bird” (e.g. Rips)
Adapt to explain these inequalities of treatment for different members within the same category.
(Sometimes referred to as graded membership)
What is another term of ‘graded membership’ in categorical mental representations?
Typicality effect
“Concepts are organised around their similarity to a central tendency” is a key assumption of which categorical theory?
Prototype model
According to the prototype model, when we think about a concept, which category member comes to mind?
The “best” category member.
What are the features of the “best” category member in the prototype model?
The aggregate of features that tend to cluster together for that concept. I.e. the most ‘typical’ or ‘likely’ set of features
Which is the more flexible and graded theory: prototype model or classical view?
Why?
Prototype model.
Category membership doesn’t necessarily entail the possession of all characteristics (contrary to the classical view).
Armstrong (1983) found typicality effects for _____ which suggested what?
Found typicality effects for categories through definition as well as similarity, suggesting a dual-model view of categorization
Typicality is sensitive to what?
E.g. When is the Category of ‘bird’ more likely to be given to chicken?
Context
Category of ‘bird’ more likely to be given to chicken if seen in a farm than a city scene
Symbolic rather than analogical representations are more suited to represent concepts, why?
Because of their flexibility
Losing which kind of knowledge can rob life of it’s meaning?
categorical or conceptual
Conceptual
Patients with what kind of memory impairments can give us answers to the neural basis of conceptual knowledge?
Evidence from patients with semantic memory impairments.
Concepts are a collection of properties (features), which activate different areas. They are not ‘mental ____’
‘mental atoms’
4 examples of disorders that can inform us about the organisation of semantic knowledge in the brain?
Semantic Dementia (SD), Herpes Simplex Encephalitis (HSE), Alzheimer’s disease, injury following stroke
In acquired disorders of semantic memory, we observe:
- _____ loss of semantic knowledge
- ______ loss of semantic knowledge
- Lesions in ______
- _______-specific impairments – e.g. ______ more than _____ (tools)
- Gradual
- Partial
- temporal cortex
- Category-specific impairments – e.g. living things more than non-living things (tools)
Gradual loss of semantic knowledge means that…
…. some aspects of the concepts meaning are lost before others
Taylor (2007)’s patient ‘JL’ illustrated which symptom of an acquired semantic memory disorder?
Gradual loss
Partial loss is…
loss of some aspects of meaning but not others.
E.g. don’t forget the concept of a helicopter, rather recall the concept but do not recall certain features such as engine.
How does partial loss of semantic memory support the semantic association network?
Suggests concepts are represented as collections of properties or features of different kinds.
Category-specific semantic deficits in acquired disorders of semantic memory are more likely to be with living things or non-living things?
Living things
Where is the lesion in Herpes Simplex Encephalitis?
Antero-medial temporal lobe.
According to Moss (1997), in which acquired disorder of semantic knowledge do patients have category-specific difficulties with living things rather than non-living things?
Herpes Simplex Encephalitis
Snowden et al (2018) provided evidence of category-specific semantic deficits in which type of patient?
Semantic dementia
What is the core assumption of the distributed-only view of semantic memory?
No specific hub for semantic knowledge.
Concepts are described by perceptual and functional attributes that involve independent brain areas that are interconnected.
What is the core assumption of the distributed + hub view of semantic memory?
(Patterson 2007)
There is a specific hub for semantic knowledge.
Modality-specific areas are interconnected but communicate ‘through’ a semantic hub.
According to Patterson and the ‘distributed + hub’ theory of semantics, where is the ‘amodal hub’ located in the brain?
Anterior temporal lobe.
Why does the distributed-only view of conceptual knowledge predict no generalised semantic impairment.
Because modality-specific aspects of the concept reside in different areas.
e.g. semantic memory of the sounds of the concept would be impaired but not the picture of the concept
Which view predicts that lesions to ‘the hub’ will lead to general, amodal, semantic impairments?
i.e. objects, sounds, pictures, words associated with that concept
Distributed + hub view
Patterson’s patients with which disorder provide evidence for a semantic hub?
Semantic Dementia
Semantic Dementia is characterized by focal lesions where?
In the anterior temporal lobes (ATL)
What do focal lesion in the anterior temporal lobes (such as in semantic dementia) lead to?
What does this provide evidence for?
Leads to the disruption of semantic representations
Evidence for a semantic hub.
(Patterson) Patients with semantic dementia tend to ”blur” the boundaries within a category and between members and non-members, e.g. finding identifying a pumpkin that is green harder than identifying a pumpkin that is orange. Which theory of mental representation does this support?
Prototypical model. Found it harder to identity the lesser typical concept.
If a patient shows an impairment in naming manipulable man-made (nonliving) objects (e.g. hammer), where is their lesion likely?
And what is this evidence for?
lesion localized in the posterior portion of temporal lobe
Category-specific deficits - independent neural systems to process modality-specific information
TMS (virtual lesion) studies (Pobric et al. 2010)
Stimulates _______ and _________.
Anterior Temporal Lobe (ATL) and Inferior Parietal Lobule (IPL)
What does temporarily disrupting the activity of Inferior Parietal Lobe cause (Pobric 2010)?
Caused category-specific impairments for naming man-made objects (tools – processing of praxis)
What does temporarily disrupting the activity of the Anterior Temporal Lobe cause (Pobric, 2010)?
Temporarily disrupting the activity of ATL caused category-general naming impairments (living things, tools)
What does evidence using TMS (virtual lesions) like Pobric (2010) tell us about the Anterior Temporal Lobe?
The anterior temporal lobe (ATL) is the region where the amodal semantic memory is localized.
Evidence using TMS (virtual lesions) like Pobric (2010) supports the existence of what?
Evidence for a graded semantic system that is distributed and is supported by an amodal hub. Modality-specific regions like IPL provide the basic “ingredients” (sensory, motor, verbal etc. ), while the ATL supports an additional amodal representation.
Evidence using TMS (virtual lesions) like Pobric (2010) shows that IPL is what?
Modality-specific.
Provides the basic “ingredients” (sensory, motor, verbal etc. ),
Anterior temporal lobe is important for semantic representations, i.e., the content of semantic knowledge
_______ and _______ areas are important to access and manipulate these representations.
Ralph 2017
Prefrontal and Temporo-parietal
