In Vivo Brain Glutathione is Higher in Older Age and Correlates with Mobility.

Brain markers of oxidative damage increase with advancing age. In response, brain antioxidant levels may also increase with age, although this has not been well investigated. Here, we used edited magnetic resonance spectroscopy to quantify endogenous levels of glutathione (GSH, one of the most abundant brain antioxidants) in 37 young [mean: 21.8 (2.5) years; 19 female] and 23 older adults [mean: 72.8 (8.9) years; 19 female]. Accounting for age-related atrophy, we identified higher frontal and sensorimotor GSH levels for the older compared with the younger adults. For the older adults only, higher sensorimotor (but not frontal) GSH was correlated with poorer balance and gait. This suggests a regionally specific relationship between higher brain oxidative stress levels and motor performance declines with age. We suggest these findings reflect an upregulation of GSH in response to increasing brain oxidative stress with normal aging. Together, these results provide insight into age differences in brain antioxidant levels and implications for motor function.

Perspective taking is associated with specific facial responses during empathy for pain.

Witnessing the distress of others can result both in empathy and personal distress. Perspective-taking has been assigned a major role in the elicitation and modulation of these vicarious responses. However, little is known about how perspective-taking affects the psychophysiological correlates of empathy vs. personal distress. We recorded facial electromyographic and electrocardiographic activity while participants watched videos of patients undergoing painful sonar treatment. These videos were watched using two distinct perspectives: a) imagining the patient's feelings ('imagine other'), or b) imagining to be in the patient's place ('imagine self'). The results revealed an unspecific frowning response as well as activity over the M. orbicularis oculi region which was specific to the 'imagine self' perspective. This indicates that the pain-related tightening of the patients orbits was matched by participants when adopting this perspective. Our findings provide a physiological explanation for the more direct personal involvement and higher levels of personal distress associated with putting oneself explicitly into someone elses shoes. They provide further evidence that empathy does not only rely on automatic processes, but is also strongly influenced by top-down control and cognitive processes.