The Importance of Auditory Cortex Abnormalities in Type I Bipolar Disorder

Functional and structural abnormalities of auditory cortices are associated with the neuropathology of schizophrenia [1-3]. Superior temporal lobe (STL) host primary and secondary auditory cortices and STLs have been associated with auditory hallucinations [2,4] and thought disorder [1] in schizophrenia. On the contrary, there are no significant differences in volumetric measurements of the STL regions in euthymic patients with bipolar disorder [5]. However, in the absence of auditory hallucinations or thought disorder in euthymia, functional studies with auditory paradigms have reported significant abnormalities in bipolar disorder [6-8]. In a recent in vivo neurochemical investigation with magnetic resonance spectroscopy study, we reported metabolic abnormalities in the left hemispheric STL in euthymic patients with bipolar disorder [9]. These findings are suggesting a specific neuropathology for bipolar disorder, which is independent of the clinical course of the disorder. STLs are among the most prominent brain regions that are explicitly influenced by the certain neuropathological processes.