Default Mode Network Connectivity Predicts Sustained Attention Deficits after Traumatic Brain Injury

Abstract

Traumatic brain injury (TBI) frequently produces impairments of attention in humans.These can result in a failure to maintain consistent goal-directed behavior. A predominantly right-lateralized frontoparietal network is often engaged during attentionally demanding tasks. However, lapses of attention have also been associated with increases in activation within the default mode network (DMN). Here, we study TBI patients with sustained attention impairment, defined on the basis of the consistency of their behavioral performance over time. We show that sustained attention impairments in patients are associated with an increase in DMN activation, particularly within the precuneus and posterior cingulate cortex. Furthermore, the interaction of the precuneus with the rest of the DMN at the start of the task, i.e., its functional connectivity, predicts which patients go on to show impairments of attention. Importantly, this predictive information is present before any behavioral evidence of sustained attention impairment, and the relationship is also found in a subgroup of patients without focal brain damage. TBI often results in diffuse axonal injury, which produces cognitive impairment by disconnecting nodes in distributed brain networks. Using diffusion tensor imaging, we demonstrate that structural disconnection within the DMN also correlates with the level of sustained attention. These results show that abnormalities in DMN function are a sensitive marker of impairments of attention and suggest that changes in connectivity within the DMN are central to the development of attentional impairment after TBI.

Serum insulin‐like growth factor‐I levels are associated with improved white matter recovery after traumatic brain injury

“…We have previously shown that after TBI, FA measurements in particular WM tracts relate to multiple neuropsychological domains 10, 11, 46. In a separate cross‐sectional cohort of patients after moderate–severe TBI and controls who were scanned once, we confirmed both lower SPCC FA and lower immediate verbal memory recall in patients after TBI compared to controls.…”

Chronology and Chronicity of Altered Resting-State Functional Connectivity after Traumatic Brain Injury

“…Further, the increased connectivity within the DMN that we observed has been interpreted by some as a compensatory response to trauma. 14,15 For example, Sharp and colleagues found that faster performance on an attentional task was associated with greater within-DMN connectivity at rest. 15 These investigators also found that increased precuneus-DMN functional connectivity at the beginning of a task resulted in less-variable reaction times during the task, and concluded that this elevated functional connectivity supports performance.…”

“…Studies of TBI have reported increased within-DMN functional connectivity during task performance, featuring prominently the PCC and precuneus regions. 14,15 In addition, graph theoretical approaches have found support for a breakdown of the PCC as a central DMN ''hub'' after injury, resulting in a more disorganized connectivity profile, when compared to healthy individuals. functionally connected to a number of distinct and distributed brain systems, [17][18][19] and this region shows alterations in functional connectivity in a number of patient samples, compared to matched controls.…”

“…20 In moderate-to-severe TBI, it has been proposed that altered connectivity patterns involving the PCC may be related to neurocognitive impairment. 12,14,15 Therefore, delineation of this region's unique connectivity profile may provide insight into neural mechanisms underlying cognitive sequelae after trauma.…”

The effect of preprocessing in dynamic functional network connectivity used to classify mild traumatic brain injury

“…Structural corticothalamic abnormalities of white matter in TBI patients are linked to more serious symptoms including posttraumatic stress disorder (Yeh et al., 2014). Obtained results cannot directly explain decreased connectivity linked to the DMN reported by previous studies (Bonnelle et al., 2011; Sharp, Scott, & Leech, 2014; Sharp et al., 2011). Our analysis is in favor of a stronger anticorrelation relationship between DMN and other cortical regions.…”