Mesencephalic raphe alterations depicted by transcranial sonography do not result in serotonergic functional impairment assessed by loudness dependence of auditory evoked potentia…

Background: Transcranial sonography (TCS) has become a new diagnostic tool in the evaluation of neuropsychiatric disorders. Hypoechogenic signal of mesencephalic raphe structures has been described as a frequent finding in unipolar depression. It remains unclear, if raphe hypoechogenicity represents a correlate for an altered serotonergic system. The loudness dependence of auditory evoked potentials (LDAEP) has been proposed as an indirect indicator of central serotonergic activity. Aim of this study was to evaluate TCS and LDAEP as independent variables of the human cerebral serotonergic system. Methods: Sonogr…