BBG/Vis Seminar: Erlend Hodneland og Svein Brekke Department of Mathmatics Universitas Bergensis SPEAKER 1: Svein Brekke
TITLE: 3D ultrasound imaging: Fundamentals and limitations: Inferior longitudinal fasiculus
Published online before print August 16, 2010, doi: 10.1073/pnas.1011043107 PNAS August 31, 2010 vol. 107 no. 35 15649-15652
“Several DTI studies confirmed widespread FA alteration indicating white-matter lesions in mTBI patients (Niogi et al., 2008; Rutgers et al., 2008). In 34 mTBI patients, Niogi and associates found microstructural white-matter and tract lesions, e.g., in the anterior corona radiata, uncinate fasciculus, genu of the corpus callosum, inferior longitudinal fasciculus, and cingulum bundle (Niogi et al., 2008). In their 21 mTBI patients, Rutgers and associates saw signs of axonal whitematter injury in multiple areas, including subcortical white matter, internal capsules, corpus callosum, fornix, and infratentorial brain stem and cerebellum (Rutgers et al., 2008). Using fiber tracking techniques, the authors also saw fiber bundle lesions in multiple areas, including supratentorialprojection fiber bundles, corpus callosum fibers, association bundles, and fronto-temporo-occipital fiber bundles (Rutgers et al., 2008).
Diffuse volume loss (Levine et al., 2008), widespread whitematter injuries (Huang et al., 2009; Niogi et al., 2008) and gray matter deafferentation (Huang et al., 2009) may explain dysfunction dysfunction of the complex central autonomic nervous system(CAN) (Benarroch, 1997) that comprises many of the above
named areas, such as the ventromedial prefrontal cortex, anterior cingulate gyrus, amygdala, suprachiasmatic hypothalamic nucleus, medial preoptic nucleus, magnocellular neurons in the supraoptic nucleus and the paraventricular nucleus, hypothalamus, arcuate nucleus, or the insula cortex (Benarroch, 1997).
Although patients do not always manifest clinically overt
autonomic dysfunction after mTBI, we assume that there is
sub-clinical autonomic dysfunction in patients who had
cerebral lesions involving CAN structures. Mild autonomic
dysfunction can be unveiled by autonomic challenge maneuvers that involve peripheral and brainstem autonomic pathways and supratentorial CAN structures.”
JOURNAL OF NEUROTRAUMA 28:1727–1738 (September 2011) ª Mary Ann Liebert, Inc. DOI: 10.1089/neu.2010.1497 Frequency Analysis Unveils Cardiac Autonomic Dysfunction after Mild Traumatic Brain Injury
In the latest Scientific American February 2012 THE COLLISION SYNDROME By Jeffrey Bartholet writes the following:
‘Christopher Giza, an associate professor of pediatric neurology and neurosurgery at the University of California, Los Angeles has done a review of the scientific literature on concussions. “We now have advanced imaging that has provided us with some of this information.”
“What is clear is that when the head, moving at significant speed, comes to an abrupt stop, the brain cells get stretched, squeezed and twisted. In their normal state, these cells function by transmitting electrical current. A part of the cell called the axon acts somewhat like a wire, conducting current between the cells. Ions shift back and forth along the axons in a controlled fashion, transmitting messages from one part of the brain to the other and to the rest of the body. When a concussion occurs, however, the membranes of brain cells get damaged and the cells become leaky, Giza says. Ions rush in and out indiscriminately. As sodium and calcium rush in, potassium rushes out. The brain needs to restore its balance.
Giza compares this process as analogous to a submarine accident: leaks are springing everywhere, and the emergency crews struggle to keep up. In the injured cells, microscopic pumps tryto get the ions back in their proper places. The pumps require energy, however, and the stressed cells face an energy crisis. At the same time, other havoc is taking place. When ions rush in, they tend to destroy the scaffolding of the cell. “it’s as if someone is in there with a saw, cutting through all the struts and supports, ” Giza says. Calcium inside the cell, moreover, can activate enzymes that can trigger the cell to destroy itself.’
Concussions thus disrupt the very anatomic integrity, the architecture of the brain. Repeated concussions, don’t allow the brain time to sufficiently recover its shape.