Nature Communications has described a rare clinical case: in a 41-year-old man with drug-resistant epilepsy and severe post-traumatic stress disorder (PTSD), during an awake operation, part of the right amygdala was temporarily inactivated - a paired cluster of neurons deep in the temporal lobes that helps recognize danger and trigger fear responses. After the procedure, he less often perceived ambiguous faces as frightened, and the trauma symptoms declined sharply.
PTSD develops after severe psychological trauma and manifests as intrusive memories, avoidance of reminders, depressed mood and constant tension. One of its key features is the tendency to interpret neutral or ambiguous signals as a threat. Researchers have long linked this to increased amygdala activity, but conventional brain imaging shows only a correlation - a statistical association that by itself does not prove causation.
The authors of the work, led by Tao Xie, John T. Willie and Peter Brunner of the University of Texas at Austin, studied a patient who first underwent isolated ablation (destruction of tissue) of the right amygdala, and two months later surgery on the hippocampus. This made it possible to separate the amygdala effect from seizure control. For comparison, 16 patients with epilepsy without PTSD were examined (seven men and nine women, mean age 37 years).
Before ablation, the man more often than healthy participants called ambiguous faces frightened. Electrical stimulation of the right amygdala caused tingling and elevated mood in him, while stimulation of the left produced almost nothing. During the procedure, doctors used electrodes to heat selected areas to 58-60 degrees while the patient was awake. Twenty minutes after inactivation of 47% of the right amygdala, he less often rated ambiguous and moderately frightened faces as scary, became slower in making decisions (reaction time increased from 0.7 to 1.1 seconds) and was less confident in his judgments.
Two months later, his PTSD scale score fell from 50 (severe disorder) to 21 - below the diagnostic threshold of 31-33. The seizure frequency did not change during this time (about 10 per month), meaning the symptom relief was not a consequence of epilepsy control. The man did not undergo psychotherapy and did not take medications targeting PTSD.
Willie calls the result "the first clear demonstration of a causal role of the right amygdala in maintaining PTSD," but emphasizes that this is an early study in a single patient. He warns that amygdala ablation is not well enough studied to be offered as a broad therapy, and calls for larger controlled trials. Among the limitations are the impossibility of a "blind" placebo during awake surgery, the influence of expectations, and the subsequent hippocampal surgery, which did not allow assessment of the long-term effect of isolated ablation.