Wednesday, November 23, 2005

Neurons Generated In The Adult Brain Learn To Respond To Novel Stimuli

Neurons Generated In The Adult Brain Learn To Respond To Novel Stimuli: "Recent research has shown, however, that new cells are added to certain areas of the brain -- including those involved with memory and the sense of smell -- well into adulthood. "

Stress : CASL

Penn Research Permits First-ever Visualization Of Psychological Stress In The Human Brain: "The results showed increased cerebral blood-flow during the 'stress test' in the right anterior portion of the brain (prefrontal cortex) -- an area long associated with anxiety and depression. More interestingly, the increased cerebral blood-flow persisted even when the testing was complete. These results suggest a strong link between psychological stress and negative emotions. On the other hand, the prefrontal cortex is also associated with the ability to perform executive functions -- such as working memory and goal-oriented behavior -- that permit humans to adapt to environmental challenges and threats. 'The message from this study is that while stress may be useful in increasing focus, chronic stress could also be detrimental to mental health,' concludes Jiongjiong Wang, PhD, Assistant Professor of Radiology and principal investigator of the study."

Imaging: arterial spin labelling

Penn Research Permits First-ever Visualization Of Psychological Stress In The Human Brain: "To date, most fMRI studies have indirectly measured changes in cerebral blood-flow and metabolism induced by neural activation, using a technique that is sensitive to the oxygenation levels in blood. "The fMRI technique employed in our study -- arterial spin labeling -- can measure cerebral flood-flow directly," states John A. Detre, MD, Associate Professor of Neurology and Radiology, and senior author of the study. "This technique is very similar to PET (positron emission tomography) scanning, except that it's entirely non-invasive -- without the need for injections or radioactivity. In this elegant technique, water molecules in subjects' own blood are 'tagged' by the magnet and used as the natural contrast agent to measure cerebral blood-flow." Researchers at Penn's Center for Functional Neuroimaging have been at the forefront of the development of this technique, and its applications to imaging brain-function during cognitive and emotional processes."
Friday, November 18, 2005

Stathmin: Loss of Fear Factor Makes Timid Mouse Bold

HHMI News: Loss of Fear Factor Makes Timid Mouse Bold: "Working in mice, the scientists, led by Howard Hughes Medical Institute investigator Eric R. Kandel at Columbia University, found that the protein stathmin is critical for both innate and learned fear. Mice without stathmin boldly explore environments where normal mice would be hesitant, and, unlike their normal counterparts, fail to develop a fear of cues that have been associated with electric shock. The scientists also found physiological changes in the brains of mice lacking stathmin that correlate to the behavioral changes they observed."
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