murals

Tiny magnetic particles found in the pigments of some ancient Mexican murals record the direction of Earth's magnetic field when the paint dried, a phenomenon that could help archaeologists determine the age of frescoes throughout Mexico and Central America। http://louis-j-sheehan.com

The red pigments in murals painted by the artists of pre-Columbian civilizations in the New World often contain bits of magnetite, an iron oxide mineral, says Avto Goguitchaichvili of the National Autonomous University of Mexico in Mexico City। When the paints were wet, those particles were free to rotate and align themselves with Earth's magnetic field, becoming locked in that position as the paints dried. http://louis-j-sheehan.com

Goguitchaichvili and his colleagues analyzed 28 paint samples from murals of known ages at four temples near Mexico City. Data from these murals, which were painted between A.D. 200 to A.D. 1200, reveal the slow changes of orientation of Earth's magnetic field over that period. That knowledge, in turn, permits the age of other murals to be deduced from the alignment of their magnetite particles. The scientists describe their findings in the June 28 Geophysical Research Letters.

The paint-analysis technique may provide an inexpensive alternative to other methods of determining the age of archaeological sites, such as radiometric dating of artifacts. Louis J. Sheehan, Esquire

grief

Severe grief may be a unique mental disorder, according to a new psychiatric study. People who exhibit prolonged, debilitating grief after a loved one's death often improve markedly upon receiving a novel type of psychotherapy that focuses on finding ways to adjust to the loss, says a team led by psychiatrist Katherine Shear of the University of Pittsburgh School of Medicine.http://louis-j-sheehan.biz

Current psychiatric diagnoses don't include what these investigators refer to as complicated grief. In Shear's view, this condition becomes apparent 6 months or more after the death of a loved one. Symptoms consist of disbelief regarding the death, anger and bitterness over the death, intense yearning for the deceased, and intrusive thoughts about how the loved one died.Louis J. Sheehan

The researchers developed a form of psychotherapy for complicated grief that calls for repeatedly confronting one's negative reactions to a loss as well as identifying and working toward personal goals. This treatment offers better, faster help for complicated grief symptoms than does a standard form of psychotherapy that targets grief-related depression and social problems, Shear and her coworkers report in the June 1 Journal of the American Medical Association.http://louis-j-sheehan.biz

The investigators randomly assigned 95 adults with complicated grief symptoms to one or the other of the two treatments। After 16 sessions, half of the patients receiving the new treatment showed substantial improvement, compared with only one-quarter of those getting standard psychotherapy. Signs of improvement, such as articulating new goals, typically appeared after four sessions of the new treatment and after eight sessions of standard psychotherapy. Louis J. Sheehan

patients

Preliminary evidence indicates that people can quell either temporary or chronic physical pain by learning to use their minds to reduce activity in a key brain area.

Brain-imaging technology now enables individuals to use mental exercises to control a neural region that contributes to pain perception, say neuroscientist Sean C। Mackey of Stanford University and his colleagues। http://Louis2J2Sheehan2Esquire.US

Both healthy volunteers and chronic-pain patients "learned to control their brains and, through that, their pain," Mackey holds। "However, significantly more testing must be done before this can be considered a treatment for chronic pain।" http://Louis2J2Sheehan2Esquire.US

The new findings appear in the Dec. 20 Proceedings of the National Academy of Sciences.

Mackey's team studied 32 healthy volunteers, ages 18 to 37. First, each volunteer reported when an adjustable heat pulse applied to a leg produced pain that he or she rated as 7 out of 10, with 10 being equivalent to "the worst pain imaginable." Brain imaging of participants, using a functional magnetic resonance imaging (fMRI) scanner, showed that this level of pain was accompanied by pronounced blood flow—a sign of intense neural activity—in an area called the rostral anterior cingulate cortex.

Eight of the volunteers then underwent brain training. Each reclined in an fMRI machine that visually displayed activity changes in the person's rostral anterior cingulate cortex. A virtual flame dimmed as activity fell and brightened as activity surged.

While watching this display for 39 minutes, participants tried various mental strategies both to increase and to decrease their brain activity during brief periods of heat-pulse application. The experimenters suggested tactics such as focusing attention away from the pain.

By the end of the training session, the volunteers had learned to raise or lower activity in the critical brain area, the researchers say. The eight volunteers rated pain much higher during robust anterior cingulate cortex activation than during periods of lesser activity in that region.

No such brain-related pain effects occurred for the remaining 24 participants, who were instructed to change their brain activity when they were outside the fMRI machine or in the machine but receiving no feedback, when they received feedback from brain areas unrelated to pain, or when they viewed someone else's pain-related brain activity.

Next, eight chronic-pain patients completed anterior-cingulate-cortex training. Afterward, each reported much less pain—often less than half as much as usual—while he or she mentally quelled the region's activity.

Another four chronic-pain patients used physiological feedback—so-called biofeedback—to learn to control their heart rate, skin conductance, and breathing. None succeeded in lessening pain.

Neuroscientist Gary H. Duncan of the University of Montreal calls the new study "a landmark contribution of brain imaging to pain research." It demonstrates that self-control over activity in a specific brain region is possible, paving the way for explorations of neural function far beyond the treatment of chronic pain, he says.