I am surprised that nobody mentioned pineal gland. As Descardes, it is where soul sits. Pineal gland also called "third eye". Pineal gland gets light information from skin and eyes and produces melatonin. Melatonin is a serotonin-derived hormone that modulates sleep patterns. People who has aphantasia also report that not having dreams. Calcification of pineal gland is proved scientifically and mostly caused by fluoride. Aphantasia might be related to this.