In pranayama practice, “the human consciousness begins to be internalized and supersensuous perceptions begin to be possible. Worlds subtler and still subtler begin to be opened up in proportion to the consciousness itself getting more and more refined, till at last the individual consciousness merges into the cosmic and the individual becomes one with the infinite.” From the Kaivalyadham brochure Pranayama Practice and Teaching.
“Now in the case of Jalandhara, the closure of the glottis, the tightening of the neck muscles, and the sharp bend of the neck in pressing the chin on chest, all contribute to exercise considerable pressure on the carotid sinus, so that the carotid nerve gets stimulated. When by constant practice this Bandha is perfected, its effect on the brain becomes accentuated and a trancelike condition may supervene.” From Chapter Two of Swami Kuvalayananda’s Pranayama (11th ed.)
Risa demonstrates one round of Brahma Mudra at a pace quickened for this video. Her eyes lead in bringing her head as far left and right as possible, then back to center. She directs eyes to tip of nose as she brings head backwards, then to a point between her eyebrows as she drops her chin all the way down to her chest. Shoulders remain relaxed and fixed throughout this preparatory exercise. It can feel pleasant to hold the most extreme positions (left, right, up, down) for 2 to 3 seconds each. One minute per round is the correct pace. (A more advanced version would be to keep eyes closed.)
A few rounds of Brahma Mudra can get you in the right state for pranayama, as it has the immediate effect of calming the mind and bringing you inward. It can also be a nice way to cap off an asana class. Just be sure to go really, really slow. It also helps relax the neck and shoulders, bringing about good circulation especially in the regions above the neck.