Hemispheric asymmetry of primary auditory cortex and Heschl's gyrus in schizophrenia and nonpsychiatric brains

• Authors: John F. Smiley, Nathan Kline Institute for Psychiatric Research; Troy A. Hackett, Vanderbilt University; Todd Preuss, Emory University; Cynthia Bleiwas, Nathan Kline Institute for Psychiatric Research; Khadija Figarsky, Nathan Kline Institute for Psychiatric Research; J. John Mann, Columbia University; Gorazd Rosoklija, Columbia University; Daniel C. Javitt, Nathan Kline Institute for Psychiatric Research; Andrew J. Dwork, Columbia University
• Journal Title: Psychiatry Research
• Volume: Volume 214, Number 3
• Publisher: Elsevier: 12 months | 2013-12-30, Pages 435-443
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.pscychresns.2013.08.009
• Subjects: Biology, Neuroscience; Psychology, General
• Keywords: Science & Technology; Life Sciences & Biomedicine; Clinical Neurology; Neuroimaging; Psychiatry; Neurosciences & Neurology; Cerebral cortex; Human; Postmortem; Stereology; Neuron number; SUPERIOR TEMPORAL GYRUS; PLANUM TEMPORALE; GRAY-MATTER; 1ST-EPISODE SCHIZOPHRENIA; ALZHEIMERS-DISEASE; CORTICAL THICKNESS; VOLUME MEASUREMENT; NEURON DENSITY; SPEECH SOUNDS; ABNORMALITIES

Abstract

Heschl's gyrus (HG) is reported to have a normal left>right hemispheric volume asymmetry, and reduced asymmetry in schizophrenia. Primary auditory cortex (A1) occupies the caudal-medial surface of HG, but it is unclear if A1 has normal asymmetry, or whether its asymmetry is altered in schizophrenia. To address these issues, we compared bilateral gray matter volumes of HG and A1, and neuron density and number in A1, in autopsy brains from male subjects with or without schizophrenia. Comparison of diagnostic groups did not reveal altered gray matter volumes, neuron density, neuron number or hemispheric asymmetries in schizophrenia. With respect to hemispheric differences, HG displayed a clear left>right asymmetry of gray matter volume. Area A1 occupied nearly half of HG, but had less consistent volume asymmetry, that was clearly present only in a subgroup of archival brains from elderly subjects. Neuron counts, in layers IIIb-c and V-VI, showed that the A1 volume asymmetry reflected differences in neuron number, and was not caused simply by changes in neuron density. Our findings confirm previous reports of striking hemispheric asymmetry of HG, and additionally show evidence that A1 has a corresponding asymmetry, although less consistent than that of HG.