Neural Correlates of Anosognosia for Hemiplegia: A White Matter Disconnection Study

Anosognosia for Hemiplegia (AHP) refers to unawareness of contralesional motor deficits, typically occurring after right brain damage. Neuroanatomical investigations of AHP have reported the involvement of distributed cortical and subcortical structures (Moro et al., 2016), whilst neuropsychological studies suggest that failures in action monitoring (Berti et al., 2005), error recognition (Moro et al., 2015) or updating of self-beliefs (Fotopoulou, 2008; Vuilleumiere, 2004;) contribute to the symptoms observed. This multifaceted nature of AHP suggests that the condition may be consequent to a disconnection between brain regions rather the damage of a single localized area. We explore this possibility using an advanced lesion analysis (BCBToolKit, Foulon et al.,2018), which allowed us to map the white matter disconnections probability in 174 patients (95 AHP patients), whilst controlling for clinical variables and concomitant symptoms (extrapersonal/peripersonal neglect, memory impairment). Results indicate that disconnections of three neural systems are evident in AHP: (1) the limbic system, (2) pre-motor loop, and (3) ventral non-motor attention network. These disconnections may account for different presentations of AHP via their established roles in (1) updating autobiographical representations of the self; (2) monitoring and error processing; and (3) attentional processes and shifting from the first- to the third-person perspective