Capgras

Question 1

Critchley 1979

Answer 1

Perceptually same but psychology different = replaced by imposter

Question 2

Ramachandran 1998

Answer 2

Usually no aversive feelings to imposter

Question 3

Silva 1996

Answer 3

Linked to violence and aggression occasionally

Question 4

Alexander 1979

Answer 4

Used to be classed as psychiatric but now organic / neurological basis e.g. patients with bilateral frontal / right hemisphere damage common

Question 5

Ellis 1997; Hirstein 1997

Answer 5

Capgras patients don’t show differential autonomic / SCR to faces

Question 6

Bauer 1984; Tranel and Damasio 1995

Answer 6

PPAs show differential SCR to faces

Question 7

Ellis and Young 1990

Answer 7

Conscious ability to recognise faces is intact i.e. ventral of Bauer’s model, but lack autonomic response (system that produces automatic emotional arousal is damaged = dorsal in Bauer’s model). “Mirror image” of PPA = double dissociation

Question 8

Bauer 1984

Answer 8

Two route anatomical model. Overt occurs in ventral visual-limbic pathway, covert in dorsal (affective).
Also patients with fronto-ventromedial lesions that didn’t show differential SCR but no Capgras so 2nd component needed?

Question 9

Breen 2000

Answer 9

Single but dual route anatomical model. Both contained within ventral structures. Structural encoding and match to FRU and then pathway diverts. Anterior temporal lobes for match to PINs and identity recognition, while simultaneously going to ventral limbic structures e.g. amygdala for affective response = parallel activation

Question 10

Milner 1995

Answer 10

Dorsal route = visually-guided action, spatial location of objects not object recognition itself

Question 11

Ungerleider and Mishkin 1982; Valyear 2006

Answer 11

Ventral occipito-temporal involved in object perception/recognition = “what” pathway. Dorsal occipito-parietal for spatial location of objects = “where” pathway

Question 12

Ellis and Lewis 2001

Answer 12

Modification to Breen model: integrative device between PINs and affective response. Mismatch = DMS. But how does it actually become a delusion - 2nd system involved?
Also dissociation between autonomic covert recog and behavioural/cognitive recog (e.g. priming) - suggests model should be adapted to include 2 types?

Question 13

Young 2008

Answer 13

Interactionist model. Delusional belief formed through disturbed phenomology/lack of autonomic response causing disturbing feelings. Belief then CAUSES patient to act like person is imposter. Feeds back so top-down as well, not one-directional.

Question 14

Hirstein and Ramachandran 1997

Answer 14

Capgras patient didn’t have delusion on phone = face-specific, like PPA

Question 15

Andersen 1988

Answer 15

Can have object Capgras e.g. for household items. But doesn’t tend to coexist with face Capgras = face-specific, like PPA (Moscovitz etc)

Question 16

Darby 2017

Answer 16

Lesion network mapping identified DMS patients all had lesions in areas which were functionally connected, and involved with familiarity processing. So could be disconnection syndrome (PPA: Gomez 2015; Song 2015).
Also 16/17 patients had lesions in areas involved in belief evaluation.

Question 17

Devinsky 2009

Answer 17

Capgras usually from bilateral frontal or right hemisphere (temporal/FFA) lesions, like PPA (Rossion 2003, Darymple 2011)

Question 18

Rojo 1991; Darby and Caplan 2016

Answer 18

Capgras in pets - so disorder can affect other modalities/networks? Maybe it’s not affecting FP network but is due to something else?

Question 19

Lewis and Sherwood 2001

Answer 19

Capgras to voices only. So not specific to faces?

Question 20

Coltheart 2007

Answer 20

2 abnormalities. First delusional belief, also damage to belief evaluation systems so delusion not rejected. Could explain transient disappearance of delusion? Also implications for CBT

Question 21

Darby and Caplan 2016

Answer 21

Catgras. Suggested disorder is due to inability to link external stimuli with appropriate autobiographical memories = disorder of WM / executive function? And then this would result in no autonomic response?

Question 22

Papageorgiou 2002

Answer 22

Capgras patients show attenuated and longer latency P300 (marker of WM so online manipulation of information). Also same in Sz! Suggests psychotic element

Question 23

Berman

Answer 23

Link to psychotic symptoms, Sz etc. Janet stopped taking seroquel (antipsychotic, dopamine and serotonin receptor antagonist) but delusion disappeared when she restarted medication

Question 24

Barton 2004

Answer 24

PPA linked to SDDs but no link to psychosis in same way as Capgras, more a disorder of perception/recognition than cognitive delusion