Lucius Fox

Chief Executive Officer of Wayne Enterprises

Radiological Society of North America

PRESSING ISSUE A normal eye before a spaceflight, left, and a flattened contour after.

Space is not good for your eyes — unless you are nearsighted, in which case it might help a bit.

Trips to weightlessness can squash the eyeballs of astronauts, swell the optic nerves and blur vision — changes that often persist long after the astronauts return to weightbound Earth. That is one more health effect that NASA will have to worry about before astronauts venture farther out into the solar system.

“When you’re talking about missions that might be two years round trip, it has to be in the back of your mind that this could be a potential limiting factor,” said Dr. Larry A. Kramer, a professor of diagnostic imaging and intervention at the University of Texas Health Science Center at Houston.

Dr. Kramer and his colleagues have put more than 35 astronauts into high-resolution magnetic resonance imaging machines. This month in the journal Radiology, they reported their findings on the first 27 astronauts they examined.

Posted at 2:15pm and tagged with: Medicine, Opthamology, Space, NASA, ISS, International Space Station, Radiology, MRI, fMRI, University of Texas, University of Texas Health Science Center at Houston, Health,.

Prior semantic processing can enhance subsequent picture naming performance, yet the neurocognitive mechanisms underlying this effect and its longevity are unknown. This functional magnetic resonance imaging study examined whether different neurological mechanisms underlie short-term (within minutes) and long-term (within days) facilitation effects from a semantic task in healthy older adults. Both short- and long-term facilitated items were named significantly faster than unfacilitated items, with short-term items significantly faster than long-term items. Region of interest results identified decreased activity for long-term facilitated items compared to unfacilitated and short-term facilitated items in the mid-portion of the middle temporal gyrus, indicating lexical-semantic priming. Additionally, in the whole brain results, increased activity for short-term facilitated items was identified in regions previously linked to episodic memory and object recognition, including the right lingual gyrus (extending to the precuneus region) and the left inferior occipital gyrus (extending to the left fusiform region). These findings suggest that distinct neurocognitive mechanisms underlie short- and long-term facilitation of picture naming by a semantic task, with long-term effects driven by lexical-semantic priming and short-term effects by episodic memory and visual object recognition mechanisms.

Posted at 11:15am and tagged with: Semantics, fMRI, Magnetic Resonance Imaging, Medicine, Science, Technology, Semantic Processing, Neurocognition, Neuroscience, Neurology, Memory, drhfquinzel,.

Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant neurodegenerative condition characterised by gradual onset of a variable combination of ataxia, chorea, epilepsy and dementia1 and is due to a (CAG)n expansion in the atrophin-1 gene.2 The pathological abnormalities consist of atrophy of the dentatorubral and pallidoluysian systems.3 Previously reported changes on brain MRI in DRPLA include atrophy of the affected areas and high-signal lesions on T2-weighted imaging in the cerebral white matter, brainstem and thalamus.4Susceptibility-weighted imaging (SWI) has not been reported in DRPLA.

Posted at 9:46pm and tagged with: MRI, fMRI, Magnetic Resonance Imaging, Science, Medicine, Technology, Dentatorubral-Pallidoluysian Atrophy, DRPLA, Neuroscience, Neurology, drhfquinzel,.