[Results of a functional magnetic resonance study of the primary auditory cortex (I): general characteristics and individual outcomes]. / Resultados en el estudio del córtex auditivo mediante resonancia magnética funcional (I): características generales y resultados individuales.

OBJECTIVE: To demonstrate and investigate the activation patterns of the primary auditory cortex (Heschl's gyrus) using functional magnetic resonance imaging (fMRI). MATERIAL AND METHODS: Pure tone stimuli at 750 Hz and 2000 Hz were delivered to the right and left ear of 32 normal-hearing volunteers (18-49 years old) in 20-second on-off cycles. The fMRI data were obtained using a 1.5 Tesla scanner and processed with SPM2. RESULTS: For both tone frequencies, bilateral hemispheric activation was identified in the transverse temporal gyrus (Heschl's gyrus) in 29 subjects (90.62 %) in response to pure tone stimuli with a probability level of p < 0.001. For monaural stimulation, bilateral hemispheric activation was observed with generally greater extent of activation in the Heschl's gyrus (HG) contralateral to the stimulated ear. CONCLUSIONS: These results demonstrate that fMRI is a useful imaging technique to investigate the auditory cortex. The contralateral auditory cortex is more responsive than the ipsilateral cortex to tones presented monaurally.

Resultados en el estudio del córtex auditivo mediante resonancia magnética funcional (I): características generales y resultados individuales / Results of a functional magnetic resonance study of the primary auditory cortex (I): general characteristics and individual outcomes

Objetivo: Investigar y demostrar los modelos de activación en el córtex auditivo primario mediante la resonancia magnética funcional (RMf). Material y métodos: Se estimuló la audición, a 32 voluntarios normo oyentes (intervalo de edad, 18-49 años), con tonos de 750 y 2.000 Hz en ciclos de 20 s de estimulación, seguidos por 20 s de reposo. Se empleó un escáner de RM de 1,5 T y la herramienta estadística SPM2. Resultados: Para ambas frecuencias (750 y 2.000 Hz) en 29 de 32 sujetos (90,62 %) se registró una activación cortical auditiva en la circunvolución de Heschl de ambos hemisferios con una p < 0,001. Ante la estimulación auditiva monoaural se ha registrado una activación cortical auditiva bilateral que, generalmente, fue mayor en el hemisferio contralateral al oído estimulado. Conclusiones: Estos resultados demuestran que la RMf es una técnica de imagen útil para la investigación del córtex auditivo. La estimulación monoaural con tonos puros activa, predominantemente, el córtex auditivo contralateral (AU)

Objective: To demonstrate and investigate the activation patterns of the primary auditory cortex (Heschl’s gyrus) using functional magnetic resonance imaging (fMRI). Material and methods: Pure tone stimuli at 750 Hz and 2000 Hz were delivered to the right and left ear of 32 normal-hearing volunteers (18-49 years old) in 20-second on-off cycles. The fMRI data were obtained using a 1.5 Tesla scanner and processed with SPM2. Results: For both tone frequencies, bilateral hemispheric activation was identified in the transverse temporal gyrus (Heschl’s gyrus) in 29 subjects (90.62 %) in response to pure tonestimuli with a probability level of p < 0.001. For monaural stimulation, bilateral hemispheric activation was observed with generally greater extent of activation in the Heschl’s gyrus (HG) contralateral to the stimulated ear. Conclusions: These results demonstrate that fMRI is a useful imaging technique to investigate the auditory cortex. The contralateral auditory cortex is more responsive than the ipsilateral cortex to tones presented monaurally (AU)