Every Muslim knows that Zikr (recitation of Quran, or chanting the names of Allah, or chanting various tasbeeh’s like Subhan Allah etc) is described in the Quran as “Verily Zikr of Allah is a tranquility for the heart” (Alaa bi zikrillahi tatmainnal quloob).
The Holy Quran when recited and recoreded over a frequency analyzer shows modulation. When one recites the Quran in Salaat the domes of the Masjids amplify the Imaam frequency of recitation driving the listeners to tears. The heart is elated and the brain becomes active. In fact, the Huffaz of Quran are known to do very well in Secular education because all areas of the brain are active due to Quranic recitation.
Similarly, the Zikr during salaat is “jehri” (loud) and “sirri” (silent). Allah ta’ala has chosen Fajr, Maghrib and Isha for “jehri” zikr. All salaats are audible and loud. Zuhr and Asr have been chosen by Allah ta’ala for silent zikr. However, the Imaam still mentions Allah’s name when changing positions.
Even the zikr made in group and in person has effects. This is what science has to say:
Dr. Ian A. Cook of UCLA and colleagues published findings in 2008 of an experiment in which regional brain activity in a number of healthy volunteers was monitored by EEG through different resonance frequencies.
Findings indicated that at 110 hz the patterns of activity over the prefrontal cortex abruptly shifted, resulting in a relative deactivation of the language center and a temporary switching from left to right-sided dominance related to emotional processing. People regularly exposed to resonant sound in the frequency of 110 or 111 hz would have been “turning on” an area of the brain that bio-behavioral scientists believe relates to mood, empathy and social behavior.
Why 110 Hz?
Many archaeo-acoustic investigations of prehistoric, megalithic structures have identified acoustic resonances at frequencies of 95-120 Hz, particularly near 110-12 Hz, all representing pitches in the human vocal range. These chambers may have served as centers for social or spiritual events, and the resonances of the chamber cavities might have been intended to support human ritual chanting.
A recent study  evaluated the possibility that tones at these frequencies might specifically affect regional brain activity. In a pilot project, 30 healthy adults listened to tones at 90, 100, 110, 120, and 130 Hz while brain activity was monitored with electroencephalography (EEG). Activity in the left temporal region was found to be significantly lower at 110 Hz than at other frequencies. Additionally, the pattern of asymmetric activity over the prefrontal cortex shifted from one of higher activity on the left at most frequencies to rightsided dominance at 110 Hz.
These findings are compatible with relative deactivation of language centers and a shift in prefrontal activity that may be related to emotional processing. (see Left Brain:Right Brain by Dan Eden). These intriguing pilot findings suggest that the acoustic properties of ancient structures may influence human brain function, andsuggest that chanting might have been used to enhance right brain activities!