Accounting for Delusional Misidentifications

Abstract

Accounts of the major DMSs are given using theoretical models of the functional components underlying recognition of familiar people. Thus, Capgras' syndrome is suggested to involve impairment of processes that can support 'covert' recognition of familiar faces in prosopagnosia. It therefore forms a potential 'mirror image' of the impairments underlying prosopagnosia, and earlier attempts to link the two conditions directly are questioned. Frégoli syndrome and intermetamorphosis are explained as defects at different stages of an information-processing chain. Not only are these accounts consistent with the association of different DMSs with different brain injuries, but they also offer both suggestions for new inquiries and predictions about possible preserved and impaired abilities.

Lost in dissociation: The main paradigms in unconscious cognition

“…Nevertheless, today evidence abounds, including on double dissociations, that these individuals produce significant SCRs when presented photos of the faces of people who are close to them (e.g., Damásio et al, 1990;Tranel et al, 1995). One of these double dissociations is particularly interesting in that it suggests a "mirror image" condition of prosopagnosia: in the Capgras delusion, it is precisely the autonomic, covert recognition of people that is impaired (SCRs are absent), leaving the patients with the distressing experience of consciously recognizing persons close to them and yet claiming that they are impostors (e.g., Ellis & Young, 1990;Ellis et al, 1997). It is possible that these two conditions reflect a double dissociation that can be mapped into a limbic dual visual system, a hypothesis first conceived by Bauer (1984): in the one case, prosopagnosia, only the neuroanatomical pathway of covert processing of emotional content, to wit, the "dorsal visual-limbic pathway" (DVLP), is unimpaired, with deficit occurring in the "ventral visual-limbic pathway" (VVLP); in the mirror case, the Capgras delusion, the unconscious, covert emotional processing is believed to be greatly or entirely compromised due to damage to the DVLP, whereas the overt recognition in the VVLP is preserved (see Ellis & Lewis, 2001, for neuroanatomical details).…”

Síndrome de Capgras en enfermedad de Alzheimer: Presentación de 2 casos

“…En estos casos el sujeto no reconoce los rostros, pero sí puede identificar a las personas (acceder al "nodo de identificación personal" por otra vía) al escuchar su voz o a través de su vestimenta, sin que el paciente se plantee la posibilidad de enfrentar a un impostor; el defecto se reconoce como propio. También, se ha establecido la dominancia del hemisferio derecho en el reconocimiento de las emociones, que puede ser independiente del reconocimiento de los rostros (18,19) .…”

“…Se dijo que el reconocimiento de un rostro implica primero el reconocerlo como objeto y luego el sentirlo como familiar (5) ; otra etapa podría ser el acceso a la información biográfica y semán-tica evocada por ese rostro, el llamado "nodo de identidad personal", al cual también podría accederse escuchando la voz de la persona (18) . Sin embargo, el procesamiento parece ser en paralelo y no sucesivo.…”

“…Sin embargo, el procesamiento parece ser en paralelo y no sucesivo. Existiría una vía occípito temporal ventral para reconocer el rostro como tal, y otra occípito límbica, más dorsal, desde la corteza de asociación visual a la corteza parietal postero-inferior y al girus cingulado para la sensación de familiaridad (18,20) . Las lesiones del girus fusiforme pueden causar prosopagnosia, pero se respeta el reconocimiento del significado emocional del rostro; se ha supuesto que el compromiso de la vía dorsal sería responsable del SC (4,20) .…”

Phenomenology and delusions: Who put the ‘alien’ in alien control?

“…For example, it is argued that the Capgras delusion (the belief that a known person has been replaced by an impostor) is triggered by an abnormal affective experience in response to seeing a known person; loss of the affective response to a familiar person's face may lead to the belief that the person has been replaced by an impostor (Ellis & Young, 1990). Similarly, the Cotard delusion (which involves the belief that one is dead or unreal in some way) may stem from a general flattening of affective responses to external stimuli (Ellis & Young, 1990), while the seed of the Frégoli delusion (the belief that one is being followed by known people who are in disguise) may lie in heightened affective responses to unfamiliar faces (Davies et al, 2001). Experience-based proposals have been provided for a number of other delusions (Breen et al, 2000;Breen et al 2001;Stone & Young, 1997;Maher, 1988;Davies, 2001;Davies et al, 2005;Langdon & Coltheart, 2000).…”