Researchers at the Netherlands Institute for Neuroscience (NIN) and Maastricht UMC are mapping the brain networks that regulate a tiny midbrain structure called the periaqueductal gray (PAG), the command center for defensive responses like fight, flight, or freeze. Their goal is to develop real-time fMRI neurofeedback therapies that could help people with PTSD and anxiety disorders learn to dampen chronic hyper-arousal.
The research
Neurobiologist Alexander Heimel and colleagues are combining two complementary approaches. In Amsterdam, the NIN team uses optogenetics and calcium imaging in mice to identify the precise cellular circuits involved in fear extinction and stress control. In Maastricht, researchers use ultra-high-field 7 Tesla functional MRI to test whether the same networks are active in humans.
The PAG is exceptionally small and buried deep in the brain stem, making it difficult to target directly. "The PAG is essentially the control center for our defensive responses," Heimel explained. "But because it is so small and located deep within the brain, we are looking for the brain regions that regulate the PAG instead. These regions may be much better suited as targets for teaching people to better control their stress responses."
By identifying the upstream cortical and subcortical regions that send inhibitory signals to the PAG, the alliance aims to establish biological targets for neurofeedback. In this paradigm, patients inside a 7T scanner receive real-time visual displays of their own upstream threat-network activity, gradually learning to consciously dampen overactive threat responses. The project also integrates this dual-focus circuit data into training curricula for early-career psychiatrists, psychologists, and clinical researchers.
Why it matters
In PTSD and anxiety disorders, the PAG can function like an unmonitored engine, running continuously without its normal regulatory brakes. This leaves the body in a state of constant alert, even when no threat is present. By mapping the higher-order brain regions that govern the PAG, researchers hope to create a non-invasive, targeted therapy that goes beyond symptom management. For anyone curious about their own brain, this work underscores that emotional regulation is not just a matter of willpower — it is rooted in specific, measurable neural circuits that can potentially be trained. Understanding these pathways may also help reduce stigma around stress-related conditions by framing them as biological, not personal, failures.
What you can do
While 7T neurofeedback is not yet available in clinics, you can support your brain's natural stress-regulation systems today. Practices like slow diaphragmatic breathing, mindfulness meditation, and regular aerobic exercise have been shown to modulate activity in brain regions involved in fear and stress control. If you struggle with chronic anxiety or hyper-arousal, consider seeking a mental health professional who can guide you through evidence-based approaches such as cognitive-behavioral therapy or biofeedback.
Source: Neuroscience News
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