The Japanese journal of neuropsychology

Full Text of this Article
in English PDF (205K)

ArticleTitle	Confabulations: Forms and mechanisms
Language	E
AuthorList	Armin Schnider
Affiliation	Division of Neurorehabilitation, Department of Clinical Neurosciences, University Hospital and University of Geneva, CH-1211 Geneva 14, Switzerland
Publication	Japanese Journal of Neuropsychology: 32 (1), 10-18, 2016
Received
Accepted
Abstract	Confabulation denotes the emergence of memories of experiences and events which never took place. It has received many hypotheses. Most of them were suggested to explain not only any type of confabulations, but also false responses in memory tests, such as, intrusions and false recognition. In this paper, evidence will be presented for a distinction between different types of false memories. Even confabulations are not a unitary phenomenon; different forms dissociate from each other. Evidence for a distinction between 4 forms with partially or totally independent mechanisms will be discussed: (1) Intrusions in free recall, also called (simple) provoked confabulations. They dissociate from all other forms and appear to constitute the price for retrieval of more information than is actually present in memory. (2) Momentary confabulations, defined as incorrect verbal productions in response to questions. This is the most common form. It may have diverse mechanisms. (3) Behaviourally spontaneous confabulation (BSpC), reflecting confusion of reality as evident in acts according to confabulations and disorientation. This form results from failure of a mechanism that we now call orbitofrontal reality filtering. This mechanism is conveyed by the posterior medial orbitofrontal cortex (area 13) and connected subcortical structures of the reward system. It filters upcoming thoughts according to their relation with ongoing reality. The underlying process appears to be extinction capacity. (4) Fantastic confabulations, which are nonsensical, illogical ideas. This form is typically associated with a confusional state, psychosis or advanced dementia. Thus, only BSpC has an experimentally validated mechanism: a failure of reality filtering emanating from the inability to abandon anticipations that no longer apply. The author stresses the need to define psychological models of confabulation and reality confusion in terms of an experimental approach that allows one to verify the hypothesis and to test its biological underpinnings.
Keywords	confabulation, disorientation, orbitofrontal cortex, source memory, monitoring