However there is a physiologic basis to support the association between PHPT and neurocognitive symptoms, as co-distribution in specific regions of the brain of parathyroid hormone 2 receptor (PTH2R) and an endogenous peptide (tuberoinfundibular peptide of 39 residues, able to locally activate PTH2R) suggested the existence of a neuromodulatory system in specific regions of the brain (52) which can be involved in auditory and limbic functions as well as stress regulation or anxiety levels. This evidence concerns the gene PTH2R and Anxiety.