Wednesday, November 5, 2014
Severity of sleep apnea impacts risk of resistant high blood pressure
Monday, September 22, 2014
Student homelessness hits another record highSeptember 22
CNN NEW YORK
A growing number of students don't have homes to return to once classes are out.
Approximately 1.3 million students enrolled in U.S. public preschools, elementary schools, middle schools and high schools schools were homeless during the 2012-13 school year.
That's up 8% from the prior year, and the highest number on record, according to the National Center for Homeless Education, funded by the Department of Education.
Tuesday, September 2, 2014
Regular marijuana use bad for teens' brains, study finds
Marijuana use is increasing, according to Lisdahl, who pointed to a 2012 study showing that 6.5 percent of high school seniors reported smoking marijuana daily, up from 2.4 percent in 1993. Additionally, 31 percent of young adults (ages 18 to 25) reported using marijuana in the last month. People who have become addicted to marijuana can lose an average of six IQ points by adulthood, according to Lisdahl, referring to a 2012
longitudinal study of 1,037 participants who were followed from birth to age 38.
Brain imaging studies of regular marijuana users have shown significant changes in their brain structure, particularly among adolescents, Lisdahl said. Abnormalities in the brain's gray matter, which is associated with intelligence, have been found in 16- to 19-year-olds who increased their marijuana use in the past year, she said. These findings remained even after researchers controlled for major medical conditions, prenatal drug exposure, developmental delays and learning disabilities, she added.
"When considering legalization, policymakers need to address ways to prevent easy access to marijuana and provide additional treatment funding for adolescent and young adult users," she said. She also recommended that legislators consider regulating levels of tetrahydrocannabinol, or THC, the major psychoactive chemical in marijuana, in order to reduce potential neurocognitive effects.
Some legalized forms of marijuana have higher levels of THC than other strains, said Alan Budney, PhD, of Dartmouth College. THC is responsible for most of marijuana's psychological effects. Some research has shown that frequent use of high potency THC can increase risk of acute and future problems with depression, anxiety and psychosis. "Recent studies suggest that this relationship between marijuana and mental illness may be moderated by how often marijuana is used and potency of the substance," Budney said. "Unfortunately, much of what we know from earlier research is based on smoking marijuana with much lower doses of THC than are commonly used today." Current treatments for marijuana addiction among adolescents, such as brief school interventions and outpatient counseling, can be helpful but more research is needed to develop more effective strategies and interventions, he added.
Additionally, people's acceptance of legalized medical marijuana use appears to have an effect on adolescents' perception of the drug's risks, according to Bettina Friese, PhD, of the http://www.pire.org/index.aspPacific Institute for Research and Evaluation in California. She presented results from a 2013 study of 17,482 teenagers in Montana, which found marijuana use among teenagers was higher in counties where larger numbers of people voted to legalize medical marijuana in 2004. In addition, teens in counties with more votes for the legalization of medical marijuana perceived marijuana use to be less risky. The research findings suggest that a more accepting attitude toward medical marijuana may have a greater effect on marijuana use among teens than the actual number of medical marijuana licenses available, Friese said.
The use of non-invasive functional neuroimaging tools has helped characterize how brain activity is disrupted in dyslexia. However, most prior work has focused on only a small number of brain regions, leaving a gap in our understanding of how multiple brain regions communicate with one another through networks, called functional connectivity, in persons with dyslexia.
This led neuroscience PhD student Emily Finn and her colleagues at the Yale University School of Medicine to conduct a whole-brain functional connectivity analysis of dyslexia using functional magnetic resonance imaging (fMRI). They report their findings in the current issue of Biological Psychiatry.
"In this study, we compared fMRI scans from a large number of both children and young adults with dyslexia to scans of typical readers in the same age groups. Rather than activity in isolated brain regions, we looked at functional connectivity, or coordinated fluctuations between pairs of brain regions over time," explained Finn.
In total, they recruited and scanned 75 children and 104 adults. Finn and her colleagues then compared the whole-brain connectivity profiles of the dyslexic readers to the non-impaired readers, which revealed widespread differences.
Dyslexic readers showed decreased connectivity within the visual pathway as well as between visual and prefrontal regions, increased right-hemisphere connectivity, reduced connectivity in the visual word-form area, and persistent connectivity to anterior language regions around the inferior frontal gyrus. This altered connectivity profile is consistent with dyslexia-related reading difficulties.
Dr. John Krystal, Editor of Biological Psychiatry, said, "This study elegantly illustrates the value of functional imaging to map circuits underlying problems with cognition and perception, in this case, dyslexia."
"As far as we know, this is one of the first studies of dyslexia to examine differences in functional connectivity across the whole brain, shedding light on the brain networks that crucially support the complex task of reading," added Finn. "Compared to typical readers, dyslexic readers had weaker connections between areas that process visual information and areas that control attention, suggesting that individuals with dyslexia are less able to focus on printed words."
Additionally, young-adult dyslexic readers maintained high connectivity to brain regions involved in phonology, suggesting that they continue to rely on effortful "sounding out" strategies into adulthood rather than transitioning to more automatic, visual-based strategies for word recognition.
A better understanding of brain organization in dyslexia could potentially lead to better interventions to help struggling readers.
The above story is based on materials provided by Elsevier. Note: Materials may be edited for content and length.
- Emily S. Finn, Xilin Shen, John M. Holahan, Dustin Scheinost, Cheryl Lacadie, Xenophon Papademetris, Sally E. Shaywitz, Bennett A. Shaywitz, R. Todd Constable. Disruption of Functional Networks in Dyslexia: A Whole-Brain, Data-Driven Analysis of Connectivity. Biological Psychiatry, 2014; 76 (5): 397 DOI: 10.1016/j.biopsych.2013.08.031
Tuesday, August 12, 2014
Brain region for resisting alcohol's allure found
A Look at How We Process Painful Experiences
Saturday, April 12, 2014
Intranasal Ketamine Delivers Rapid Antidepressant Effect
Dr. James Murrough
Three hours is enough to help prevent mental health issues in teens
Date: October 3, 2013 Source: Université de Montréal Summary: The incidence of mental health issues amongst 509 British youth was reduced by 25 to 33% over the 24 months following two 90-minute group therapy sessions. Almost one-in-four American 8 to 15 year olds has experienced a mental health disorder over the past year. We know that these disorders are associated with a plethora of negative consequences. This study shows that teacher delivered interventions that target specific risk factors for mental health problems can be immensely effective at reducing the incidence of depression, anxiety and conduct disorders in the long term.