Is the right anterior superior temporal sulcus involved in speaker-identity recognition? : a study using transcranial direct current stimulation

Neuroimaging studies have revealed regions in the human brain that respond preferentially to human voices. These regions are mostly located along the superior temporal gyrus and sulcus (STG/S). It has been hypothesized that the right anterior STG/S is crucial for voice-identity recognition because the amplitudes of anterior STG/S neuroimaging responses correlate positively with voice-identity recognition performance. Here, my aim was to test this hypothesis by using non-invasive transcranial direct current stimulation (tdcs) in a randomized double-blind sham- controlled within-participants design. 24 neurotypical participants were familiarized with four unfamiliar speakers voices and were then tested on voice-identity and speech recognition. While performing the voice-identity and speech recognition test, participants received anodal, cathodal, and sham tdcs on three different days, respectively. As hypothesized, voice-identity recognition was improved when applying anodal tdcs to the right anterior STG/S as compared to cathodal and sham. However, this was only the case on day three. My results support the hypothesis that the right anterior STG/S is behaviourally relevant for identifying a speakers voice.