The “self-awareness–anosognosia” paradox explained: How can one process be associated with activation of, and damage to, opposite sides of the brain?

摘要

Healthy volunteers engaged in self-referential tasks such as reflecting on their personality traits exhibit mostly left lateralized brain activation, yet patients with lack of awareness of their deficit suffer from predominantly right hemisphere damage. How can the same basic process of self-awareness be associated with opposite sides of the brain? Anosognosia and self-awareness substantially differ on important dimensions and thus should not be equated. It is proposed that (1) anosognosia does not actually result from uniquely right hemisphere damage; (2) self-awareness and anosognosia do not constitute unitary concepts and encompass multiple other related processes, most likely associated with activity in distinct anatomical networks; and (3) impaired awareness of deficit is mostly caused by problems with self-monitoring, pre-/post-brain damage comparisons of performance, and episodic memory, and is more passive, unintentional, and about the body. Self-awareness produced by inviting participants to intentionally and actively think about more mental aspects of the self relies on judgements, inferential reasoning, imagination, and semantic memory. Consequently, the “self-awareness–anosognosia” paradox is only apparent. Furthermore, the claim that healthy self-awareness is located in the right hemisphere because anosognosia results from damage to this side of the brain must be fallacious. ? 2016 Informa UK Limited, trading as Taylor & Francis Group.