Study Casts Doubts on Brain Regions for Self-Awareness
Case of brain-damaged yet self-aware man suggests that other regions are involved
THURSDAY, Aug. 23 (HealthDay News) -- The case of a self-aware man with extensive damage to brain regions thought to be critical for self-awareness suggests that a more diffuse brain network and other brain networks are involved, according to a study published online Aug. 22 in PLoS One.
Carissa Philippi, Ph.D., from the University of Iowa in Iowa City, and colleagues describe self-awareness in a man with extensive bilateral brain damage to three brain regions believed to be critical for self-awareness: the insular cortex, the anterior cingulate cortex, and the medial prefrontal cortex.
The researchers note that the man had severe amnesia that partially affected his "autobiographical self." However, his self-awareness was fundamentally intact. He displayed core self-awareness, including basic self-recognition and sense of self-agency and ownership over behavioral actions and sensory representations. The man also showed extended self-awareness, an elaborate self-concept built on autobiographical memories, as well as introspective self-awareness, a controlled reflection allowing the development of accurate knowledge about the self.
"The results suggest that the insular cortex, anterior cingulate cortex, and medial prefrontal cortex are not required for most aspects of self-awareness," Philippi and colleagues conclude. "Our findings are compatible with the hypothesis that self-awareness is likely to emerge from more distributed interactions among brain networks, including those in the brainstem, thalamus, and posteromedial cortices."