Investigation of Heschl's gyrus and planum temporale in patients with schizophrenia and bipolar disorder: A proton magnetic resonance spectroscopy study

Abstract

Background Superior temporal cortices include brain regions dedicated to auditory processing and several lines of evidence suggest structural and functional abnormalities in both schizophrenia and bipolar disorder within this brain region. However, possible glutamatergic dysfunction within this region has not been investigated in adult patients. Methods Thirty patients with schizophrenia (38.67 ± 12.46 years of age), 28 euthymic patients with bipolar I disorder (35.32 ± 9.12 years of age), and 30 age-, gender- and education- matched healthy controls were enrolled. Proton Magnetic Resonance Spectroscopy data were acquired using a 3.0T Siemens MAGNETOM TIM Trio MR system and single voxel Point REsolved Spectroscopy Sequence (PRESS) in order to quantify brain metabolites within the left and right Heschl's Gyrus and Planum Temporale of superior temporal cortices. Results There were significant abnormalities in Glutamate (Glu) (F(2,78)=8.52, p<0.0001), n-Acetyl Aspartate (tNAA) (F(2,81)=5.73, p=0.005), Creatine (tCr) (F(2,83)=5.91, p=0.004) and Inositol (Ins) (F(2,82)=8.49, p<0.0001) concentrations in the left superior temporal cortex. In general, metabolite levels were lower for bipolar disorder patients when compared to healthy participants. Moreover, patients with bipolar disorder exhibited significantly lower tCr and Ins concentrations when compared to schizophrenia patients. In addition, we have found significant correlations between the superior temporal cortex metabolites and clinical measures. Conclusion As the left auditory cortices are associated with language and speech, left hemisphere specific abnormalities may have clinical significance. Our findings are suggestive of shared glutamatergic abnormalities in schizophrenia and bipolar disorder.

Main Effects of Diagnoses, Brain Regions, and their Interaction Effects for Cerebral Metabolites in Bipolar and Unipolar Depressive Disorders

“…For example, Glu concentrations in the left Heschl’s Gyrus and Planum Temporale of the superior temporal gyrus of patients with schizophrenia and BDd have been proved to be lower than healthy cohorts10. Comparing to schizophrenia patients and healthy cohorts, lower Glu, NAA, Cr and Inositol in patients with BDd suggested that a possible location-specific abnormality was existed in the dominant hemisphere of auditory cortices in patients with BDd11. As the main excitatory transmitter in the human brain, altered Glx was found in gray matter areas of patients with BDd1213.…”

“…As a putative marker of glial cells, the level of mI has been shown to be significantly reduced in UDd while increased in BDd paitents714. Cr plays a key role in maintaining energy stores, and its level is considered relatively constant141618, but recent research have report that Cr levels are not stable in some psychiatric populations1119.…”

Perisylvian GABA levels in schizophrenia and bipolar disorder

“…Since auditory hallucinations are one of the most frequent symptoms of schizophrenia and abnormalities of the auditory cortices are associated with hallucinations [15], auditory cortices are among the most relevant brain regions in schizophrenia. In a recent 1 H-MRS study, we have detected metabolic abnormalities within the left hemisphere superior temporal lobe in both schizophrenia and bipolar disorder [16]. Neural synchronization deficits with auditory tasks may indicate GABAergic abnormalities in auditory cortices in bipolar disorder and schizophrenia [17].…”

Heschl’s Transverse Gyri: Anatomy and Morphological Variations

“…It is located in the posterior part of the area on the superior surface of the temporal lobe or, the planum temporale. Heschl's gyrus is also known as transverse temporal gyrus (2,3). The morphology of this gyrus has been reported to be variable (3).…”

“…Besides auditory disorders, Heschl's gyrus morphology may be affected in different diseases. For example, it has been reported that the volume of Heschl's gyrus is reduced in patients with schizophrenia (2). Therefore, identification of Heschl's gyrus on sectional imaging techniques, especially on MR imaging is important.…”