I will not write anything more about value of संध्या & ब्रह्म मुहूर्त in this post. But this research gives vital hint about its importance. If you are performing संध्या or at least waking up at 4, you will surely connect with the research and importance of this critical period of the day.
We say that, this is time to connect self with the Universe. With ब्रह्म, to the self. Research says that, this is the time when our senses are most efficiency to even perceive weakest signals. This is the time to sharpen our worldview, to even remain receptive to the unknown world.