Human brain mapping
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Human brain mapping · Jan 2016
DBSproc: An open source process for DBS electrode localization and tractographic analysis.
Deep brain stimulation (DBS) is an effective surgical treatment for movement disorders. Although stimulation sites for movement disorders such as Parkinson's disease are established, the therapeutic mechanisms of DBS remain controversial. ⋯ In this paper, we explain our methodology and provide validation with anatomical and tractographic data. This method can be used to help investigate mechanisms of action of DBS, inform surgical and clinical assessments, and define new therapeutic targets.
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Human brain mapping · Jan 2016
White matter abnormalities are associated with chronic postconcussion symptoms in blast-related mild traumatic brain injury.
Blast-related mild traumatic brain injury (mTBI) is a common injury among Iraq and Afghanistan military veterans due to the frequent use of improvised explosive devices. A significant minority of individuals with mTBI report chronic postconcussion symptoms (PCS), which include physical, emotional, and cognitive complaints. However, chronic PCS are nonspecific and are also associated with mental health disorders such as posttraumatic stress disorder (PTSD). ⋯ These white matter abnormalities were significantly associated with physical PCS severity even after accounting for PTSD symptoms, but not with cognitive or emotional PCS severity. A mediation analysis revealed that mTBI + LOC significantly influenced physical PCS severity through its effect on white matter integrity. These results suggest that white matter abnormalities are associated with chronic PCS independent of PTSD symptom severity and that these abnormalities are an important mechanism explaining the relationship between mTBI and chronic physical PCS.
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Human brain mapping · Dec 2015
Brain structural and functional connectivity in Parkinson's disease with freezing of gait.
To use a multimodal approach to assess brain structural pathways and resting state (RS) functional connectivity abnormalities in patients with Parkinson's disease and freezing of gait (PD-FoG). ⋯ This study suggests that FoG in PD can be the result of a poor structural and functional integration between motor and extramotor (cognitive) neural systems.
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Human brain mapping · Dec 2015
Neural correlates of temporal summation of second pain in the human brainstem and spinal cord.
Temporal summation of second pain (TSSP) occurs when painful stimuli are presented repetitively (≥ 0.33 Hz) and results from a C-fibre evoked enhancement (or "wind-up") of the dorsal horn neurons. Based on electrophysiological studies in intact animals, windup is considered a purely central phenomenon. With advancements in functional MRI (fMRI), we can now probe the central mechanisms of this pain response in humans. ⋯ FMRI results identified enhanced activity in the spinal cord dorsal horn at C6 in response to the TSSP condition. Additionally, multiple areas of the brainstem (RVM and PAG) showed greater responses with the TSSP condition. These results suggest that, in humans, increased pain perception in the TSSP condition is reflected by greater responses in the dorsal horn and in regions known to play a role in the descending modulation of pain, which may modulate the spinal cord response.
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Human brain mapping · Dec 2015
Regional volumes in brain stem and cerebellum are associated with postural impairments in young brain-injured patients.
Many patients with traumatic brain injury (TBI) suffer from postural control impairments that can profoundly affect daily life. The cerebellum and brain stem are crucial for the neural control of posture and have been shown to be vulnerable to primary and secondary structural consequences of TBI. The aim of this study was to investigate whether morphometric differences in the brain stem and cerebellum can account for impairments in static and dynamic postural control in TBI. ⋯ Moreover, across all participants, worse postural control performance was associated with lower WM volume in the pons, medulla, midbrain, superior and middle cerebellar peduncles and cerebellum. This is the first study in TBI patients to demonstrate an association between postural impairments and reduced volume in specific infratentorial brain areas. Volumetric measures of the brain stem and cerebellum may be valuable prognostic markers of the chronic neural pathology, which complicates rehabilitation of postural control in TBI.