Frontolimbic affective bias and false narratives from brain disease.

Since the nineteenth century, clinicians and investigators have systematically evaluated the origin of delusions and psychotic thinking. One major clue to understanding the neurobiological underpinnings of delusions is the emergence of false narratives from brain disease. In addition to delusions themselves, there are a range of other false narratives not due to deliberate lying and resulting from neurological disorders, including provoked confabulations, fantastic confabulations, false memories, magical thinking, dream delusions, and "fantastic thinking". A comparison of their characteristics, similarities, and differences suggest a hypothesis: despite different sources for their false narrative experiences, such as unusual thoughts or perceptions, all false narratives from brain disease involve erroneous or mismatched "affective biases" applied to the experiences. Affective labels usually signal the sense of rightness, sense of familiarity, and the external vs. internal origin of an experience, and they can be altered by limbic neuropathology. The location and involvement of neuropathology that facilitates false narratives involves frontolimbic regions and their connections, particularly on the right. Future investigations can focus on frontolimbic mechanisms involved in the provision of the intrinsically-linked affective biases, which indicate the nature and external/internal origin of experiences.