01880nas a2200217   4500008004100000245011000041210006900151260001200220300001600232490000700248520116000255100001201415700001901427700001501446700001601461700001601477700001501493700001901508700001601527856011901543       2023                        eng d00aUnexpected sound omissions are signaled in human posterior superior temporal gyrus: an intracranial study0 aUnexpected sound omissions are signaled in human posterior super  c07/2023  a8837–88480 v333 aContext modulates sensory neural activations enhancing perceptual and behavioral performance and reducing prediction errors. However, the mechanism of when and where these high-level expectations act on sensory processing is unclear. Here, we isolate the effect of expectation absent of any auditory evoked activity by assessing the response to omitted expected sounds. Electrocorticographic signals were recorded directly from subdural electrode grids placed over the superior temporal gyrus (STG). Subjects listened to a predictable sequence of syllables, with some infrequently omitted. We found high-frequency band activity (HFA, 70-170 Hz) in response to omissions, which overlapped with a posterior subset of auditory-active electrodes in STG. Heard syllables could be distinguishable reliably from STG, but not the identity of the omitted stimulus. Both omission- and target-detection responses were also observed in the prefrontal cortex. We propose that the posterior STG is central for implementing predictions in the auditory environment. HFA omission responses in this region appear to index mismatch-signaling or salience detection processes.1 aCho, H.1 aFonken, Y., M.1 aAdamek, M.1 aJimenez, R.1 aLin, J., J.1 aSchalk, G.1 aKnight, R., T.1 aBrunner, P.  uhttps://www.neurotechcenter.org/publications/2023/unexpected-sound-omissions-are-signaled-human-posterior-superior