fMRI studies increasingly examine functions and properties of non-primary areas of human auditory cortex. However there is currently no standardized localization procedure to reliably identify specific areas across individuals such as the standard ‘localizers’ available in the visual domain. Here we present an fMRI ‘voice localizer’ scan allowing rapid and reliable localization of the voice-sensitive ‘temporal voice areas’ (TVA) of human auditory cortex. We describe results obtained using this standardized localizer scan in a large cohort of normal adult subjects. Most participants (94%) showed bilateral patches of significantly greater response to vocal than non-vocal sounds along the superior temporal sulcus/gyrus (STS/STG). Individual activation patterns, although reproducible, showed high inter-individual variability in precise anatomical location. Cluster analysis of individual peaks from the large cohort highlighted three bilateral clusters of voice-sensitivity, or “voice patches” along posterior (TVAp), mid (TVAm) and anterior (TVAa) STS/STG, respectively. A series of extra-temporal areas including bilateral inferior prefrontal cortex and amygdalae showed small, but reliable voice-sensitivity as part of a large-scale cerebral voice network. Stimuli for the voice localizer scan and probabilistic maps in MNI space are available for download.

The functional role of the superior temporal sulcus (STS) has been implicated in a number of studies, including those investigating face perception, voice perception, and face–voice integration. However, the nature of the STS preference for these ‘social stimuli’ remains unclear, as does the location within the STS for specific types of information processing. The aim of this study was to directly examine properties of the STS in terms of selective response to social stimuli. We used functional magnetic resonance imaging (fMRI) to scan participants whilst they were presented with auditory, visual, or audiovisual stimuli of people or objects, with the intention of localising areas preferring both faces and voices (i.e., ‘people-selective’ regions) and audiovisual regions designed to specifically integrate person-related information. Results highlighted a ‘people-selective, heteromodal’ region in the trunk of the right STS which was activated by both faces and voices, and a restricted portion of the right posterior STS (pSTS) with an integrative preference for information from people, as compared to objects. These results point towards the dedicated role of the STS as a ‘social-information processing’ centre.

The integration of emotional information from the face and voice of other persons is known to be mediated by a number of "multisensory" cerebral regions, such as the right posterior superior temporal sulcus (pSTS). However, whether multimodal integration in these regions is attributable to interleaved populations of unisensory neurons responding to face or voice or rather by multimodal neurons receiving input from the two modalities is not fully clear. Here, we examine this question using functional magnetic resonance adaptation and dynamic audiovisual stimuli in which emotional information was manipulated parametrically and independently in the face and voice via morphing between angry and happy expressions. Healthy human adult subjects were scanned while performing a happy/angry emotion categorization task on a series of such stimuli included in a fast event-related, continuous carryover design. Subjects integrated both face and voice information when categorizing emotion-although there was a greater weighting of face information-and showed behavioral adaptation effects both within and across modality. Adaptation also occurred at the neural level: in addition to modalityspecific adaptation in visual and auditory cortices, we observed for the first time a crossmodal adaptation effect. Specifically, fMRI signal in the right pSTS was reduced in response to a stimulus in which facial emotion was similar to the vocal emotion of the preceding stimulus. These results suggest that the integration of emotional information from face and voice in the pSTS involves a detectable proportion of bimodal neurons that combine inputs from visual and auditory cortices.

Temporal voice areas showing a larger activity for vocal than non-vocal sounds have been identified along the superior temporal sulcus (STS); more voice-sensitive areas have been described in frontal and parietal lobes. Yet, the role of voice-sensitive regions in representing voice identity remains unclear. Using a functional magnetic resonance adaptation design, we aimed at disentangling acoustic- from identity-based representations of voices. Sixteen participants were scanned while listening to pairs of voices drawn from morphed continua between 2 initially unfamiliar voices, before and after a voice learning phase. In a given pair, the first and second stimuli could be identical or acoustically different and, at the second session, perceptually similar or different. At both sessions, right mid-STS/superior temporal gyrus (STG) and superior temporal pole (sTP) showed sensitivity to acoustical changes. Critically, voice learning induced changes in the acoustical processing of voices in inferior frontal cortices (IFCs). At the second session only, right IFC and left cingulate gyrus showed sensitivity to changes in perceived identity. The processing of voice identity appears to be subserved by a large network of brain areas ranging from the sTP, involved in an acoustic-based representation of unfamiliar voices, to areas along the convexity of the IFC for identity-related processing of familiar voices.

Normal listeners effortlessly determine a person's gender by voice, but the cerebral mechanisms underlying this ability remain unclear. Here, we demonstrate 2 stages of cerebral processing during voice gender categorization. Using voice morphing along with an adaptation-optimized functional magnetic resonance imaging design, we found that secondary auditory cortex including the anterior part of the temporal voice areas in the right hemisphere responded primarily to acoustical distance with the previously heard stimulus. In contrast, a network of bilateral regions involving inferior prefrontal and anterior and posterior cingulate cortex reflected perceived stimulus ambiguity. These findings suggest that voice gender recognition involves neuronal populations along the auditory ventral stream responsible for auditory feature extraction, functioning in pair with the prefrontal cortex in voice gender perception.