ABSTRACT
The key auditory processing regions of the brain are found in the superior temporal cortex. The primary auditory cortex is approximately coincident with Heschl’s gyrus on the superior surface of the superior temporal gyrus (STG) lying within the Sylvian fissure (Da Costa et al. 2011). In humans, the STG also contains perhaps the most prominently asymmetrical brain area: the auditory association cortex of the planum temporale. This cortical area lies posterior and lateral to Heschl’s gyrus, thus contributing to the hemispheric asymmetry of the posterior Sylvian fissure. This region in the posterior STG plays a key role in phonological processing and forms part of the receptive language region often identified as Wernicke’s area. The anterior STG is also implicated in syntactic processing. With regards to psychosis, the auditory region offers one of the clearest associations between psychotic symptoms and brain structure, as it is activated during auditory hallucinations (Shergill et al. 2000; Ropohl et al. 2004). Electrophysiological (“mismatch”) responses to anomalous sounds in a series or words at the end of a sentence are also reduced in patients with schizophrenia. At a structural level, reduced gray matter in the STG is one of the most replicated structural changes in the disorder.
