title: Extensive left temporal pole damage does not impact on theory of mind abilities.
abstract: The temporal poles (TPs) are among the brain regions that are often considered as the brain network sustaining our ability to understand other people's mental states or "Theory of Mind" (ToM). However, so far the functional role of the left and right TPs in ToM is still debated, and it is even not clear yet whether these regions are necessary for ToM. In this study, we tested whether the left TP is necessary for ToM by assessing the mentalizing abilities of a patient (C.M.) diagnosed with semantic dementia. Converging evidence from detailed MRI and (18)F-fluoro-2-deoxy-d-glucose PET examinations showed a massive atrophy of the left TP with the right TP being relatively unaffected. Furthermore, C.M.'s atrophy encompassed most regions of the left TP usually activated in neuroimaging studies investigating ToM. Given C.M.'s language impairments, we used a battery of entirely nonverbal ToM tasks. Across five tasks encompassing 100 trials, which probed the patient's ability to attribute various mental states (intentions, knowledge, and beliefs), C.M. showed a totally spared performance. This finding suggests that, despite its consistently observed activation in neuroimaging studies involving ToM tasks, the left TP is not necessary for ToM reasoning, at least in nonverbal conditions and as long as its right counterpart is preserved. Implications for understanding the social abilities of patients with semantic dementia are discussed.
authors.affiliation: Psychological Sciences Research Institute, Université catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Caroline
authors.initials: C
authors.lastname: Michel
authors.forename: Laurence
authors.initials: L
authors.lastname: Dricot
authors.forename: Renaud
authors.initials: R
authors.lastname: Lhommel
authors.forename: Cécile
authors.initials: C
authors.lastname: Grandin
authors.forename: Adrian
authors.initials: A
authors.lastname: Ivanoiu
authors.forename: Agnesa
authors.initials: A
authors.lastname: Pillon
authors.forename: Dana
authors.initials: D
authors.lastname: Samson
mesh_terms: D001284:Atrophy / Q000175:diagnosis / Q000523:psychology; D001931:Brain Mapping / Q000379:methods*; D003071:Cognition / Q000502:physiology; D057180:Frontotemporal Dementia / Q000175:diagnosis* / Q000523:psychology; D006801:Humans; D007807:Language Tests; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D013702:Temporal Lobe / Q000473:pathology*; D056345:Theory of Mind / Q000502:physiology