Walking in a forest is just a way to give your brain a controlled distraction. The greenery pulls the brain out of a state of constant alertness, which activates the parasympathetic nervous system and lowers cortisol. That downtime lets the prefrontal cortex and hippocampus reorganize synapses, especially the connections that regulate emotion. You can see it as a gentle pruning that boosts gray matter in those areas, and the vagus nerve is a key conduit. So, every time you stroll under a canopy, you’re essentially tuning the brain’s plasticity for better focus and less stress.