MICROCRYSTALS OF CALCITE IN THE PINEAL GLAND OF THE HUMAN BRAIN

摘要

A new form of biomineralization has been found in the pineal gland of the human brain. The crystals are 10 to 20 mum in length and have well-defined morphologies. Several structure types have been identified using scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) showed that the crystals contain only the elements calcium, carbon and oxygen. Selected-area electron diffraction (SAED) and near infrared Raman spectroscopy established that the crystals are calcite. With the exception of the otoconia structure of the inner ear, this is the first report of the presence of non-pathological calcite in the human body. These microcrystals are believed to be responsible for the previously observed second harmonic generation (SHG) in pineal tissue samples and they may also exhibit piezoelectricity, suggesting a unique electromechanical biological transducer mechanism in the human brain.