The previous two studies showed what happens over years—shrinking amygdalas, thickening prefrontal cortexes. This one shows what happens in ninety minutes.
A 2020 study took 25 healthy adults, ages 24 to 52, and divided them into two groups. One completed the Ashtanga yoga primary series. The other performed an assigned series of physical exercises. Both groups underwent PET/MR brain scans before and immediately after.
The finding: the yoga group showed altered glucose metabolism—the brain’s energy consumption—in seven distinct regions. The exercise group didn’t.
🧠 The Seven Regions
The areas that changed tell a story:
Hippocampus and parahippocampus — memory formation and spatial navigation. Where we encode experience.
Striatum — reward processing and habit formation. Where repetition becomes pattern.
Amygdala — fear and emotional processing. The same region that shrinks over years of practice showed immediate metabolic shifts after one session.
Insula — interoception, the sense of the body from within. Where we feel ourselves breathing, our heart beating, our balance shifting.
Anterior midbrain — motor control and arousal. Where movement originates.
Cerebellum — coordination, timing, motor learning. Where vinyasa becomes fluid.
Not random scatter. A constellation of regions involved in memory, emotion, body awareness, and coordinated movement.
⚡ Why Primary Series?
The researchers specifically chose Ashtanga primary series—not generic yoga, not relaxation poses. The structured sequence with its counted breaths, bandha engagement, and consistent format creates conditions the brain can recognize and respond to.
This matters. The control group did physical exercise—movements that challenge the body—but their brains didn’t show the same pattern of changes. Something about the integration of breath, movement, gaze, and internal awareness activates these regions differently.
The eight limbs describe this integration. Asana coordinates the body. Pranayama regulates the breath. Pratyahara draws attention inward. In primary series, these happen simultaneously—and the brain lights up accordingly.
🔬 Immediate and Cumulative
What strikes me is the relationship between this study and the long-term research. The amygdala that shrinks over eight years showed immediate metabolic changes after one practice. The regions governing memory and attention that thicken over time were already working differently after ninety minutes.
Perhaps the structural changes are simply the accumulated residue of thousands of these immediate shifts. Each practice is a training session. The brain adapts to what we repeatedly ask of it.
The yogis called this samskara—the grooves worn by repeated action. The neuroscientists call it neuroplasticity. Same phenomenon, different vocabulary.
🪷 The Practice Itself
This is why the sequence matters. Why we return to the same poses in the same order. Why the breath counts stay consistent.
The brain recognizes patterns. It responds to ritual. When we step onto the mat and begin Surya Namaskar A, the brain already knows what’s coming—and it prepares accordingly.
Novelty has its place. But transformation lives in repetition.
— MJH