[289] Amnesia

Memory and Confabulation

Confabulation describes the emergence of memories of events and experiences that have never taken place. There are different forms with diverse mechanisms. One form, which we call behaviourally spontaneous confabulation, reflects a confusion of reality: the patients act according to their confabulations and are disoriented regarding time, place and their current role. Using experimental exploration of patients and imaging methods (PET, high-density EEG etc.) in healthy subjects, we discovered a mechanisms which is deficient in reality confusing patients and appears to be essential for maintaining thought and behaviour in phase with ongoing reality. We call it "Orbitofrontal reality filtering". In brief, whenever a thought/memory is activated, it passes after 200-300 ms through this filter, which depends on the posterior medial orbitofrontal cortex and adapts the upcoming thought's cortical format depending on its relation with current reality. The underlying mechanism seems to be extinction capacity.

We are currently exploring the relationship and precise timing between this (anterior limbic) mechanism and the encoding of information (dependent on the posterior limbic system).

Books:

  • Schnider A (1997) Verhaltensneurologie. Die neurologische Seite der Neuropsychologie. Stuttgart: Thieme.
  • Schnider A (2004) Verhaltensneurologie. Die neurologische Seite der Neuropsychologie. Eine Einführung für Ärzte und Psychologen, 2. Aufl. Stuttgart: Thieme.
  • Schnider A (2008) Neurologie du Comportement. Paris: Elsevier - Masson.
  • Schnider A (2008) The Confabulating Mind. How the Brain Creates Reality. Oxford, New York: Oxford University Press.
  • Schnider A (2018) The Confabulating Mind. How the Brain Creates Reality, 2nd edition. Oxford, New York: Oxford University Press.

Recent articles on Orbitofrontal Reality Filtering, confabulation & encoding:

  • Thézé-Boissonnet R, Manuel AL, Nahum L, Guggisberg A, Schnider A. Simultaneous Reality Filtering and Encoding of Thoughts: The Substrate for Distinguishing between Memories of Real Events and Imaginations? Frontiers in Behavioral Neuroscience 2017;11:216.
  • Schnider A, Nahum L, Ptak R. What does extinction have to do with confabulation? Cortex 2017;87:5-15.
  • Liverani MC, Manuel AL, Nahum L, Guardabassi V, Tomasetto C, Schnider A. Children's sense of reality: The development of orbitofrontal reality filtering. Child Neuropsychology 2015;23(4):408-421.
  • Manuel AL, Schnider A. Differential processing of immediately repeated verbal and non-verbal stimuli: an evoked-potential study. European Journal of Neuroscience 2016;43(1):89-97. 
  • Liverani MC, Manuel AL, Guggisberg A, Nahum L, Schnider A. No Influence of Positive Emotion on Orbitofrontal Reality Filtering: Relevance for Confabulation. Frontiers in Behavioral Neuroscience 2016;10:98.
  • Schnider A. Orbitofrontal reality filtering. Frontiers in Behavioral Neuroscience 2013;7:67.

 

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