Module 6 Flashcards
What is Cognitive Neuropsychology?
Cognitive Neuropsychology: combination of both cognitive psychology and neuropsychology with emphasis on understanding the mind
- For cognitive neuropsychology we believe there is a relationship between brain and mind
- Emphasis is on the working of the mind
What is Cognitive Neuropsychiatry?
Cognitive Neuropsychiatry: applications of cognitive neuropsychology methods to understand/explain disorders of higher-level cognition
- Delusions - higher-level cognition
What is a delusion?
What is a delusion?
- A false belief based on incorrect inference about external reality that is firmly sustained despite what almost everyone else believes and despite what constitutes incontrovertible and obvious proof or evidence to the contrary
What is Monothematic delusions?
Monothematic delusions only concerns a single topic/issue/experience
What are Encapsulated beliefs?
Encapsulated beliefs
- (single topic) do not interact with the rest of their beliefs
What are Delusional misidentification syndromes?
Delusional misidentification syndromes
- the belief that a person, place, or object has been somehow changed or altered
What is Capgras Delusion?
Capgras delusion is the belief that someone emotionally close to you has been replaced by an imposter
- Father, mother spouse, children, pets, objects
- Often specific to one person or a set of persons
What are Consistent features of Capgras?
Consistent features of Capgras
- Delusion often specific to one person or set of persons
- Patient is convinced that although the person is identical to the original person in everyway, but they are different (they don’t know why)
- Belief resistant to criticism, however patients can recognise the idea is absurd
- False person is never mistaken for someone else or given a different name
- Patient cannot explicitly identify the differences between the current and true person
- Delusion tends to occur in familiar contexts (home)
- Patients adapts well to imposter
What is the Affective Integration Model of Capgras Delusion?
Hirstein & Ramachandran (1997) Affective Integration Model
- Capgras due to a failure to process information about face recognition (temporal lobe) and limbic system
- Limbic system activation - the effective response from seeing familiar people
Capgras – failure to integrate ongoing memories of a person across episodes (time)
- Damage prevents patient from integrating current encounter with person to the stored “file” on that person and so creates a new file
Limbic activation (emotion) acts as a glow to help link successive episodes with that person
what is the Ellis and Young (1990) Affective Response Model for Capgras Delusion?
Ellis and Young (1990) Affective Response Model
- Normal face processing – dual route (Bauer, 1984)
- Ventral route – seeing a face allows you to recognise a familiar person
- Dorsal route – affective response to the face
- Prosopagnosia – damage to the ventral pathway (face recognition pathway)
- Capgras delusion – damage to the dorsal pathway
Lack of affective response → conflict within the person they adopt a rationalisation strategy
- (a way to make sense of the conflicting information)
What is the Breen et al (2000) model of Capgras Delusion?
- How does it explain prospognosia?
- What is a limitation of the model?
Breen et al (2000) model of Capgras Delusion
Similar to the Bruce and young model of face recognition
- Prosopagnosia: damage to the Face Recognition Units (FRU) unable to get information to the Person Identity Nodes
- Capgras: disconnection from the FRU to the “affective response to familiar stimuli”
Problem with the model
- Does not explain how the lack of affective response turns into a delusion
- Ellis and Lewis (2001): modified affective response model tries to address this
Explain the Ellis and Lewis (2001) Modified Affective Response Model?
Capgras patient lacks the autonomic response (b) to a familiar face
Capgras patient not consciously aware of what is different but “believes/feels” there is something different
- Face recognition units are normal, which activates PIN (a) which goes into the integrative device
- But because Capgras patients lack the “affective response to familiar stimuli”, you do not have a normal amount of activation in this system
- Thus when the “affective response to familiar stimuli” links with the PIN in the intergrative device, there is a miss match
- To come to terms with this miss match, a person with Capgras delusions attirbutes that miss match to the fact that the original person has been replaced
The delusional belief is a specific hypothesis to explain this difference
Patient readjusts their belief to match their autonomic arousal level
Explain Coltheart et al’s Two Factor Theory for Capgras Delusion.
Capgras patient lacks the autonomic response to a familiar face (First factor that contributes to capgras delusions)
- However, this is not sufficient to end up with capgras delusions, there must be a second deficit
Damage to the right hemisphere (second deficit)
- Right lateral prefrontal cortex
- Weakened belief evaluation system
What is Fregoli Delusion?
Fregoli Delusion
- False belief that people you know are following you around but because they are wearing a disguise you cant recognise them
- “People I know are following me around but in disguise so I can never recognize them”
no similarity between person and disguise, they look dissimilar then usual
How does the Affective Response Model Explanation (Ellis & Lewis 2001) explain Fregoli Delusion?
Affective Response Model Explanation (Ellis & Lewis 2001)
- Strong autonomic response to all faces
- Thus, their face recognition units is not highly active
- But their Affective Response to Familiar Stimuli is very high
- In the Integrative Device, there is a lack of congruence between the level of face recogntion response and the affective response
To make sense of the incongruency in the integrative device, they believe people are wearing disguises
Explain Coltheart et al’ s Two Factor Theory for Fregoli Delusion?
Coltheart et al (2007, 2010, 2011) Two Factor Theory
- Although the hyper- arousal responses to faces is necessary for Fregoli delusion it is not sufficient
- Because these are patients that have high levels of skin responses to all faces, that do not develop this delusion
- Thus there must be two deficits
- Because these are patients that have high levels of skin responses to all faces, that do not develop this delusion
First deficit: excessive SCR over-activity to all faces
Second deficit: Damage to the right hemisphere [Right lateral prefrontal cortex] = impaired belief evaluation system (second deficit)
- they take on board the false belif that these people are wearing disguises
what is Cotard Delusion?
What is Cotard Delusion
- The belief that you are dead or parts of your body is dead
- Doesn’t have to be your whole body
