A new neuroimaging study showed that people suffering from posttraumatic stress disorder (PTSD) exhibited increased activation in the amygdala region of the brain when shown surprised and neutral facial expressions. The same phenomenon was observed in identical twins of these individuals who did not suffer from PTSD.

The study, which was published in the Journal of Psychiatric Research, sheds new light on the neural mechanisms underlying the development of PTSD.

PTSD is a condition that develops in approximately 20% of individuals exposed to psychological trauma in their lifetime. It is defined by wide clusters of symptoms that include intrusive memories, negative alterations in mood, heightened levels of arousal, and other symptoms. Currently, there are many treatment options available for PTSD; however, for some patients, the treatments offered do not provide clinical relief.

Twelve-hour (12 h) ultradian rhythms are a well-known phenomenon in coastal marine organisms. While 12 h cycles are observed in human behavior and physiology, no study has measured 12 h rhythms in the human brain. Here, we identify 12 h rhythms in transcripts that either peak at sleep/wake transitions (approximately 9 AM/PM) or static times (approximately 3 PM/AM) in the dorsolateral prefrontal cortex, a region involved in cognition. Subjects with schizophrenia (SZ) lose 12 h rhythms in genes associated with the unfolded protein response and neuronal structural maintenance. Moreover, genes involved in mitochondrial function and protein translation, which normally peak at sleep/wake transitions, peak instead at static times in SZ, suggesting suboptimal timing of these essential processes.

You can grasp a hand. You can also grasp a concept. One is literal. One is metaphorical. Our brains know the difference, but would we be able to understand the latter without the former?

Previous studies have suggested that our understanding of metaphors may be rooted in our bodily experience. Some functional MRI, o fMRI, brain imaging studies have indicated, for example, that when you hear a metaphor such as “she had a rough day,” regions of the brain associated with tactile experience are activated. If you hear, “he’s so sweet,” areas associated with taste are activated. And when you hear action verbs used in a metaphorical context, like “grasp a concept,” regions involved in motor perception and planning are activated.

A study by University of Arizona researcher Vicky Lai, published in the journal Brain Research, builds on this research by looking at when, exactly, different regions of the brain are activated in metaphor comprehension and what that tells us about the way we understand language.