Neurophysiology, Basic And ClinicalIs frontal lobe involved in the generation of auditory evoked P50?Weisser, Regina; Weisbrod, Matthias1, CA; Roehrig, Miriam1; Rupp, André; Schroeder, Johannes1; Scherg, MichaelAuthor Information Section of Biomagnetism, Neurology Department and 1Psychiatry Department, University of Heidelberg, Voss-Str. 4, 69115 Heidelberg, Germany CACorresponding Author Received 9 July 2001; accepted 11 August 2001 NeuroReport: October 29th, 2001 - Volume 12 - Issue 15 - p 3303-3307 Buy Abstract This study examined the functional substrate of P50 suppression. Auditory evoked potentials (AEPs) and magnetic fields (AEFs) were recorded from healthy subjects simultaneously and analyzed using spatio-temporal source analysis. The resulting equivalent dipole model for the AEP consisted of one source in the auditory cortex (AC) of each hemisphere and an radially oriented medial frontal source, both with maximum AEP activity around 50 ms. The frontal source was functionally separated from the AC sources since it peaked significantly later and showed significantly larger P50 amplitude suppression. P30m showed neither suppression nor substantial frontal activity. In sum, this study relates P50 suppression to reduction of AC source activity and is the first to yield direct evidence for frontal involvement in P50 suppression. © 2001 Lippincott Williams & Wilkins, Inc.