Disruption of the ascending arousal network in acute traumatic disorders of consciousness

Model System:

TBI

Reference Type:

Journal article

Accession No.:

J84136

Journal:

Neurology (formerly the Archives of Neurology)

Year, Volume, Issue, Page(s):

2019 , 93, 13, e1281-e1287

Publication Website:

Abstract:

Study investigated whether ascending arousal network (AAn) connectivity is reduced in patients presenting with traumatic coma. The AAn is a collection of subcortical pathways that connect the rostral brainstem tegmentum to the hypothalamus, thalamus, and basal forebrain. High-angular-resolution diffusion imaging was performed in 16 patients with acute severe traumatic brain injury who were comatose on admission and in 16 matched controls. Probabilistic tractography was used to measure the connectivity probability (CP) of AAn axonal pathways linking the brainstem tegmentum to the hypothalamus, thalamus, and basal forebrain. To assess the spatial specificity of CP differences between patients and controls, CP was also measured within 4 subcortical pathways outside the AAn. Compared to controls, patients showed a reduction in AAn pathways connecting the brainstem tegmentum to a region of interest encompassing the hypothalamus, thalamus, and basal forebrain. When each pathway was examined individually, brainstem-hypothalamus and brainstem-thalamus CPs, but not brainstem-forebrain CP, were significantly reduced in patients. Only 1 subcortical pathway outside the AAn showed reduced CP in patients. This study provides initial evidence for the reduced integrity of axonal pathways linking the brainstem tegmentum to the hypothalamus and thalamus in patients presenting with traumatic coma. Findings support current conceptual models of coma as being caused by subcortical AAn injury. AAn connectivity mapping provides an opportunity to advance the study of human coma and consciousness.

Author(s):