Browsing by Author "Barlow, Karen Maria"

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    Functional Connectivity of the Anterior Cingulate Cortex in Children with Post-traumatic Headache
    (2020-05-19) Ofoghi, Zahra; Barlow, Karen Maria; Dewey, Deborah; Yeates, Keith Owen; Bray, Signe L.; Noel, Melanie
    Post-traumatic headache (PTH) is among the most common persistent post-concussion symptoms following mild traumatic brain injury (mTBI). Investigating structural and functional neuroimaging correlates of pain or headache can help to understand biological mechanisms behind persistent PTH. In this dissertation, a systematic review was conducted to examine the neuroimaging correlates of headache or pain following mTBI. Here, in the adult populations with PTH, there was evidence to suggest alterations in descending pain modulatory mechanisms but there was a lack of research in the pediatric populations with PTH. The remainder of this thesis addresses this knowledge gap by investigating alterations in central pain processing networks with a focus on the anterior cingulate cortex (ACC). To do this, functional connectivity (FC) between the ACC and other pain-related regions was explored in children with PTH and compared to those without PTH following mTBI and uninjured healthy controls. The influence of a pre-injury headache history on ACC FC was then investigated. As other cognitive and affective symptoms are also common in children with PTH, the associations between attention problems and anxiety and ACC FC were studied. Functional connectivity of the perigenual ACC-cerebellum and the subgenual ACC-DLPFC were different in children with PTH compared to healthy controls. No significant differences, however, were found in children with and without PTH. Functional connectivity between the ventral ACC areas (rostral and perigenual) and cerebellum was significantly affected by a past history of headache problems; children with PTH and a history of headache having decreased negative FC. In children with PTH, better attention performance was associated with stronger subgenual ACC-cerebellum FC. Anxiety, however, was not associated with the ACC FC and pain-related regions. Taken together, this dissertation provides evidence of alterations in descending modulatory pain processing mechanisms in children with PTH following mTBI. Further, for the first time, neuroimaging evidence supported the effect of pre-injury headaches on connectivity between pain-related regions in children with PTH. Future studies should explore FC of other pain-related regions (e.g. periaqueductal regions, cerebellum) in central pain processing networks and their relationship with recovery.
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    Measuring Brain Connectivity and Hemodynamic Alterations Following Pediatric Mild Traumatic Brain Injury in the Primary Motor Cortex
    (2015-01-08) Urban, Karolina; Dunn, Jeffrey Frank; Barlow, Karen Maria
    Concussion, or mild traumatic brain injury, is a growing concern especially among the pediatric population. Symptoms may persist beyond one month after injury and result in long term disability called Post-Concussion Syndrome (PCS). There is a lack of measures to quantitatively monitor and explore pathophysiological mechanisms of PCS. We hypothesized that since fiber tracts are often impacted in concussion, functional activation and inter-hemispheric brain communication may be impaired. We used functional near-infrared spectroscopy (fNIRS) to quantify the magnitude of activation and inter-hemispheric communication between motor cortices using a coherence analysis. Subjects completed a resting state and tapping paradigm. We detected differences between patients and controls in coherence, suggesting alterations in inter-hemispheric communication. Given the critical need for a quantitative biomarker for recovery following a concussion, we present this data to highlight the potential of fNIRS, coupled with coherence analysis, as a sensitive measure to detect functional changes.