Medical Bulletin 26/October/2022

When we're happy, we smile. The corners of our mouths move out and up, our cheeks lift, and the skin around our eyes crinkles. But does it work the other way? Can posing our muscles in a smile brighten our mood? This question has been part of a long-standing debate among psychology researchers about whether facial expressions influence our emotional experience, an idea known as the facial feedback hypothesis. In a recent paper published in Nature Human Behavior, an international collaboration of researchers led by Stanford research scientist Nicholas Coles found strong evidence that posed smiles can, in fact, make us happier.

The researchers created a plan that included three well-known techniques intended to encourage participants to activate their smile muscles. One-third of participants were directed to use the pen-in-mouth method, one-third were asked to mimic the facial expressions seen in photos of smiling actors, and the final third were given instructions to move the corners of their lips toward their ears and lift their cheeks using only the muscles in their face.

Reference:

Nicholas Coles et al,JOURNAL:Nature Human Behaviour

A region of the brain called the amygdala is responsible for powerful emotions like fear. Now, researchers have found the amygdala may also be to blame for overeating. Cold Spring Harbor Laboratory (CSHL) Professor Bo Li has discovered a group of neurons in the amygdala that drives mice to eat fatty or sugary foods-even when they're not hungry. Therapeutics targeting these neurons could lead to new treatments for obesity with minimal side effects.

Like most people, mice also tend to find foods high in fat and sugar the tastiest. They may indulge in these treats for pleasure, rather than for survival. The neurons Li and his colleagues studied trigger this behavior, called hedonic eating.

Reference:

JOURNAL Bo Li et al,Nature Neuroscience DOI 10.1038/s41593-022-01178-3

Gene mutations in tumors affect radiation sensitivity

A new Northwestern Medicine study identifies common and rare gene mutations that impact radiation resistance and sensitivity, an important step toward providing more individualized and effective radiotherapy for patients with cancer.

Studying tumors from 27 different types of cancer, investigators profiled 92 genes with 400 unique mutations and determined the impact of these genes on radiation response.

They developed a computational algorithm that nominated mutations in genes that were likely to affect sensitivity to radiation. Scientists tested these mutations by placing them in several human cells and assessed their impact using high-volume arrayed phenotypic profiling.

Reference:

Dr. Mohamed Abazeed, et al,"The mutational landscape of cancer's vulnerability to ionizing radiation",Clinical Cancer Research