"Looks familiar, but I do not know who she is": The role of the anterior right temporal lobe in famous face recognition

Abstract

Processing a famous face involves a cascade of steps including detecting the presence of a face, recognizing it as familiar, accessing semantic/biographical information about the person, and finally, if required, production of the proper name. Decades of neuropsychological and neuroimaging studies have identified a network of occipital and temporal brain regions ostensibly comprising the 'core' system for face processing. Recent research has also begun to elucidate upon an 'extended' network, including anterior temporal and frontal regions. However, there is disagreement about which brain areas are involved in each step, as many aspects of face processing occur automatically in healthy individuals and rarely dissociate in patients. Moreover, some common phenomena are not easily induced in an experimental setting, such as having a sense of familiarity without being able to recall who the person is. Patients with the semantic variant of Primary Progressive Aphasia (svPPA) often recognize a famous face as familiar, even when they cannot specifically recall the proper name or biographical details. In this study, we analyzed data from a large sample of 105 patients with neurodegenerative disorders, including 43 svPPA, to identify the neuroanatomical substrates of three different steps of famous face processing. Using voxel-based morphometry, we correlated whole-brain grey matter volumes with scores on three experimental tasks that targeted familiarity judgment, semantic/biographical information retrieval, and naming. Performance in naming and semantic association significantly correlates with grey matter volume in the left anterior temporal lobe, whereas familiarity judgment with integrity of the right anterior middle temporal gyrus. These findings shed light on the neuroanatomical substrates of key components of overt face processing, addressing issues of functional lateralization, and deepening our understanding of neural substrates of semantic knowledge.

Keywords: Face processing; Neurodegenerative disorders; Primary progressive aphasia; Semantic knowledge; Voxel-based morphometry.

Fig. 1 –

UCSF Famous Faces Battery. a) Two examples of the stimuli used in the Confrontation Naming task, where subjects are asked to retrieve the proper name of each famous face presented. b) Two examples of the stimuli used in the Semantic Association task, in which subjects have to select, among three famous faces, the two sharing a semantic connection (i.e., being in the same profession). c) Two examples of the stimuli used in the Familiarity Judgment task, where subjects are asked to select the familiar face among three unfamiliar distractors.

Fig. 2 –

Famous face processing breakdown in neurodegenerative disorders. The results of the three tasks of the UCSF Famous Faces Battery allow descriptive comparisons of famous face processing deficits across different clinical profiles [average across clinical spectra, error bars represent standard deviation]. See Table 1 for details. AD = Alzheimer’s disease spectrum; FTD = frontotemporal dementia spectrum; svPPA = semantic variant Primary Progressive Aphasia; lvPPA = logopenic variant Primary Progressive Aphasia; nfvPPA = nonfluent variant Primary Progressive Aphasia.

Fig. 3 –

Brain regions associated with famous face naming performance. a) Voxel-based morphometry identify regions of GM atrophy that correlated with performance in the Confrontation Naming task across all 123 participants (p < .001, FWE-corrected at the cluster level). b) For descriptive purposes, behavioral scores are plotted as a function of grey matter volumes at the most significant cluster [colors indicate the different clinical groups].

Fig. 4 –

Brain regions associated with famous face semantic retrieval. a) The results of the voxel-based morphometry analyses conducted across 123 participants demonstrates the correlation between left-sided temporal pole GM volume and the performance in the Semantic Association task p < .001, FWE-corrected at the cluster level). b) For descriptive purposes, behavioral scores are plotted as a function of grey matter volumes at the most significant cluster [colors indicate the different clinical groups].

Fig. 5 –

Brain regions associated with famous face familiarity judgment. a) Voxel-based morphometry identify regions of GM atrophy that correlated with performance in the Familiarity Judgment task across all participants (p < .001, FWEcorrected at the cluster level). b) For descriptive purposes, behavioral scores are plotted as a function of grey matter volumes at the most significant cluster [colors indicate the different clinical groups].

Fig. 6 –

Isolating naming, semantic retrieval, and familiarity judgment. The three effects are overlaid on five axial slices and a rendered template brain (left and right hemisphere).