Researchers from Germany, Scotland and Switzerland have notched up a brain imaging first by capturing a participant in the full throes of a spontaneous panic attack, whilst also having a concurrent recording of her heart rate.
Kai Spiegelhalder and colleagues were able to use the woman's elevated heart rate to provide an objective marker for the course of her panic attack. The 59-year-old was unmedicated and had no prior history of panic attacks. She did have restless legs syndrome - a condition characterised by an comfortable urge to move the legs.
Inspection of the woman's brain activity during the panic episode showed that her heart-rate was positively correlated with activity in her left amygdala - the walnut-shaped brain structure known to be involved in emotional learning. There was also some association between panic and activity in the woman's left insula. This brain region is involved in the detection and processing of bodily states. These observations are consistent with research conducted with panic disorder patients who have been provoked into having an attack with the use of drugs. "It appears likely that the insula may be involved early in the onset of panic, acting as an 'internal alarm'," the researchers said.
Another observation was that as the woman's heart rate increased, activity decreased in her left middle temporal gyrus - a bulge in the part of the cortex near the ear. Some previous studies have actually made the opposite observation with panic disorder patients. "...[D]ecreased temporal lobe activity is perhaps specific to healthy individuals experiencing their first attack," the researchers said.
Spiegelhalder's team warned their results should be treated with caution, especially since they involved a single case study. However, they said their data "do suggest, to some extent, that the neural mechanisms involved in a spontaneous panic attack share some similarity with those proposed to play a role in patients with panic-related disorder."
Spiegelhalder, K., Hornyak, M., Kyle, S., Paul, D., Blechert, J., Seifritz, E., Hennig, J., Tebartz van Elst, L., Riemann, D., & Feige, B. (2009). Cerebral correlates of heart rate variations during a spontaneous panic attack in the fMRI scanner. Neurocase, 15 (6), 527-534 DOI: 10.1080/13554790903066909