Neurophysiological correlates of dysregulated emotional arousal in severe traumatic brain injury

Brain volume loss contributes to arousal and empathy dysregulation following severe traumatic brain injury

“…In sum, atrophy of the amygdala and thalamus may be critical in determining the extent of deficits in both arousal and empathy in patients with TBI while the hippocampus may have a role limited to the cognitive appraisal of empathic abilities. Extending upon the results of our previous research ( Fisher et al, 2015 , Rushby et al, 2013a , Rushby et al, 2013b ), the current study examined the degree of correspondence between measures of physiological arousal (SCL and alpha power) and self-reported emotional empathy, with atrophy in the amygdala and thalamus representing two primary ventral-stream structures. Examination of the hippocampus was included to assess correspondence between cognitive appraisal of empathy and atrophy in dorsal-stream structures.…”

“…Blunted alpha changes were largest in lateral-temporal regions, regions typically associated with TBI damage. A follow up study investigated levels of arousal during an emotion processing task, as well as whether disturbances in either process was related to atrophy of structures in the brain following TBI ( Fisher et al, 2015 ). TBI participants showed this hypoarousal (i.e., blunted alpha change) in an emotional context, but only the control group showed a relationship with brain volume, such that larger left insula and right amygdala correlated positively with responsivity of alpha to task demands.…”

“…The amygdala has traditionally been associated with the processing of emotionally salient stimuli and has been suggested to play a role in affective empathy ( Fisher et al, 2015 , Leigh et al, 2013 , Rankin et al, 2006 ). Furthermore, since the amygdala mediates autonomic responses to emotional stimuli, damage to this structure is likely to be accompanied by abnormalities in arousal and responsivity to such stimuli ( Fisher et al, 2015 , Newsome et al, 2013 ). Amygdala volume correlates positively with both skin conductance levels ( Williams et al, 2001 ) and alpha power ( Fisher et al, 2015 ).…”

“…Furthermore, since the amygdala mediates autonomic responses to emotional stimuli, damage to this structure is likely to be accompanied by abnormalities in arousal and responsivity to such stimuli ( Fisher et al, 2015 , Newsome et al, 2013 ). Amygdala volume correlates positively with both skin conductance levels ( Williams et al, 2001 ) and alpha power ( Fisher et al, 2015 ). The thalamus has been similarly implicated in the mediation of arousal.…”

Physiological underarousal as a mechanism of aggressive behavior in university athletes with a history of concussion

“…In any closed‐head injury, diffuse axonal damage results in a variable pattern of symptomatology; however, due to the increased vulnerability of the ventromedial prefrontal cortex (vmPFC)—a principal autonomic regulator—physiological underarousal at baseline is commonly observed (Fisher, Rushby, McDonald, Parks, & Piguet, 2015; Rushby et al., 2013, 2016). The vmPFC's location proximal to the orbital bones of the skull (Morales, Diaz‐Daza, Hlatky, & Hayman, 2007) renders it more susceptible to disruption following rapid acceleration/deceleration of the head; as a result, attenuated arousal is experienced across the spectrum of injury severity (Iverson & Lange, 2009)—even after milder injuries (Alcock, Gallant, & Good, 2018; Baker & Good, 2014; van Noordt & Good, 2011).…”