Delta (3hz – 0.2hz) – Deep, dreamless sleep. Intuition. Empathy. Brainwave expert Judith Pennington calls it the doorway to Universal Consciousness and “A radar that scans the environment and psychically picks up information and energy.” According to British physicist C. Maxwell Cade “There have been reports that delta waves appear at the onset of paranormal phenomena.” (More information can be found in Cade’s book The Awakened Mind)

The brain has two hemispheres that operate somewhat independently from one another. The two hemispheric structures of the brain are connected by a large nerve, called the corpus callosum, which sends information back and forth between the two sides of the brain. In most people, the left hemisphere controls language, logical thinking, and analytic processes and the right side contains the centers for emotion, intuition, and non-linear creative thinking.
In 1956, the famous neuroscientist W. Gray Walter published the results of studying thousands of test subjects using photic stimulation, showing their change in mental and emotional states. He also learned that photic stimulation not only altered brainwaves, but that these changes were occurring in areas of the brain outside of vision. In Walter’s words:
Want to use it as a serious tool for self-development, long-term meditation support, etc.? Find a supplier that is in alignment with your own values and knows what they are doing. E.g. Holosync have decent entrainment technology, but make ridiculous claims and are very salesy and pushy...  I have tried several and always come back to the Monroe Institute and their well tried and tested sessions, mainly from the gateway experience and lucid dreaming series.
So I began to look at other instances in which the nervous system is being stimulated on a daily basis and discovered that sports science has a lot to teach us about this. Whether you are practicing yoga, meditation, using brainwave entrainment, or working out, it’s all pushing the nervous system. One of the things that sports science teaches us is that the nervous system waxes and wanes like a sine wave in its capacity to recover from, and grow from, the stimulation we give it every day. Static levels of stimulation, where you’re getting the same smack every day, day in and day out, do not allow for the fact that there are times when the nervous system is at its peak to handle the stimulation, and there are other times when the nervous system is in its trough, or valley period, when it is harder for it to recover from stimulation.
To further illustrate how brainwave entrainment enhances your meditation practice, here is an explanation. When an experienced and advanced meditator is hooked into equipment that reads their brainwave patterns, it is most common for their brain to move from whatever state they are in before they meditate (normally a Beta or higher Alpha state) slowly down into a deep Theta rhythm.  Very advanced meditators are able to bring their brain all the way into a Delta state, which is most normally where deep sleep occurs.  To be able to bring the brain into these deep brainwave states through the process of meditation can take years of meditative practice, and lots of discipline.
Neural oscillations are rhythmic or repetitive electrochemical activity in the brain and central nervous system. Such oscillations can be characterized by their frequency, amplitude and phase. Neural tissue can generate oscillatory activity driven by mechanisms within individual neurons, as well as by interactions between them. They may also adjust frequency to synchronize with the periodic vibration of external acoustic or visual stimuli.[3]