The Role of the Left and Right Anterior Temporal Poles in People Naming and Recognition

Abstract

People’s identity recognition and the neural correlates underlying this process are still a matter of debate. While neuropsychological reports on single cases show a crucial role of the left anterior temporal lobe (ATL) in proper naming, and of the right ATL in people’s identification, reviews are less consistent. Moreover, it is still controversial whether familiarity and personal semantics access rely on amodal processes or follow modality-dependent paths. To disentangle these issues, we tested, in a parallel-group design, neurologically unimpaired subjects in two famous people recognition tasks after anodal tDCS over the left or right ATL or after a placebo stimulation condition. In the famous people recognition task, subjects were presented with visual (face recognition) or auditory (voice recognition) stimuli and subjects had to judge whether stimuli belonged to a famous or non-famous person (familiarity test); then, if the stimulus was recognized as famous, participants had to provide personal semantic information about the character; finally, to investigate proper naming, subjects were asked to name the famous person. While right ATL anodal tDCS increased accuracy in famous faces (but not voices) judgment and personal semantics retrieval, left ATL stimulation increased proper naming for both visual and auditory stimuli. Our data support a key role of the right ATL in famous people recognition and access to personal semantics from visual inputs, while the left ATL seems crucial for proper naming, which seems to occur at a later stage, when presentation modality no longer affects the process.