The auditory cortex network in the posterior superior temporal area

Objective This study investigated the function and networks of the auditory cortices in the posterior lateral superior temporal area (PLST) using a combination of electrical cortical stimulation and diffusion tensor imaging (DTI). Methods Seven patients with intractable focal epilepsy in which the PLST auditory cortices were identified during the electrical cortical stimulation were enrolled in this study (left side: four patients, right side: three patients). Electrical stimulation at 50 Hz was applied to the chronically implanted subdural electrodes to identify the PLST auditory cortices. DTI was used to identify the subcortical fibers originating from the PLST auditory cortices found by electrical stimulation. Results Electrical stimulation of the right PLST auditory cortices induced hearing impairment in three patients and left side stimulation elicited hearing illusory sounds in four patients. DTI detected the middle longitudinal fasciculus (MLF) in all patients, the superior longitudinal fasciculus (SLF) in six patients and the inferior fronto-occipital fasciculus (IFOF) in three patients, originating from the PLST auditory cortices. Conclusion This study suggests different functional roles between the right and left PLST auditory cortices, and the networks originating from these areas. Significance MLF, SLF and IFOF might be associated with the auditory processing.