Hearing suppression induced by electrical stimulation of human auditory cortex

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Neurosurgery

Background:

• Electrical Stimulation Functional Mapping (ESFM) is used in neurosurgery.
• The superior temporal gyrus (STG) is a key area for auditory processing.
• Previous research has not extensively documented hearing suppression during STMS.

Purpose of the Study:

• To investigate the phenomenon of hearing suppression during ESFM.
• To identify the specific cortical sites responsible for hearing suppression within the STG.
• To correlate these sites with known auditory cortical fields.

Main Methods:

• ESFM was performed on neurosurgery patients.
• Auditory event-related potentials (ERPs) were recorded using intracranial electrodes.
• Stimulation sites were mapped and their effects on hearing documented.

Main Results:

• Three subjects experienced hearing suppression during stimulation of anterior lateral Heschl's gyrus (HG) and posterior lateral STG.
• This suppression affected both ears and persisted post-stimulation.
• Stimulation of core auditory cortex (posterior medial HG) evoked sounds or tinnitus, affecting only the contralateral ear and not persisting.

Conclusions:

• Confirms a rare experimental observation of hearing suppression.
• Identifies specific auditory belt and parabelt fields within the STG associated with hearing suppression.
• Differentiates the effects of stimulating core auditory cortex versus surrounding fields.