On the definition and interpretation of voice selective activation in the temporal cortex

Abstract

Regions along the superior temporal sulci and in the anterior temporal lobes have been found to be involved in voice processing. It has even been argued that parts of the temporal cortices serve as voice-selective areas. Yet, evidence for voice-selective activation in the strict sense is still missing. The current fMRI study aimed at assessing the degree of voice-specific processing in different parts of the superior and middle temporal cortices. To this end, voices of famous persons were contrasted with widely different categories, which were sounds of animals and musical instruments. The argumentation was that only brain regions with statistically proven absence of activation by the control stimuli may be considered as candidates for voice-selective areas. Neural activity was found to be stronger in response to human voices in all analyzed parts of the temporal lobes except for the middle and posterior STG. More importantly, the activation differences between voices and the other environmental sounds increased continuously from the mid-posterior STG to the anterior MTG. Here, only voices but not the control stimuli excited an increase of the BOLD response above a resting baseline level. The findings are discussed with reference to the function of the anterior temporal lobes in person recognition and the general question on how to define selectivity of brain regions for a specific class of stimuli or tasks. In addition, our results corroborate recent assumptions about the hierarchical organization of auditory processing building on a processing stream from the primary auditory cortices to anterior portions of the temporal lobes.

The Effect of Familiarity on Neural Representations of Music and Language

“…), areas along the superior and middle temporal gyri are more active for stimuli with vocalizations than without vocalizations (Belin et al, 2000;Fecteau et al, 2004). In a direct comparison between speech and musical instruments, the posterior portions of the superior and middle temporal gyri were more active to human voice than to nonvocal sounds (Bethmann & Brechmann, 2014). In the current study, activity did not differ across the three different conditions involving the voice, confirming that these areas are generally active in response to the human voice.…”

Optical imaging during toddlerhood: brain responses during naturalistic social interactions

“…We know from previous research that adults and infants display increased responses in the anterior-middle STS region to human voice relative to nonvocal sounds. 46,48,[65][66][67][68][69] Indeed, on the same day, the infants in this study were also involved in a study of social visual and auditory (vocal) cues prior to taking part in this live session, and group data from the first study showed a similar localized pattern of activation to vocal > nonvocal sounds accompanied by visual social cues. 48 However, we believe that the observed responses cannot be wholly explained by voice-selective activation.…”

Interaction of language, auditory and memory brain networks in auditory verbal hallucinations

“…As observed in anatomical studies, some of the regions involved have functions in multiple networks. The best such example is the superior temporal area where the secondary auditory cortex overlaps with Wernicke’s area (Bethmann and Brechmann, 2014). Patients with AVH exhibit abnormal anatomical and functional connections in all three networks.…”