Identification of Proper and Common Names in the Anterior Temporal Lobe: An FMRI Study

Temporal lobe epilepsy is a neurological disease that affects millions of individuals worldwide. They are usually treated through surgical resection of portions of the anterior temporal lobe (ATL). Surgical resection is effective for seizure control, but produces language and verbal memory deficits such as anomic aphasia, which adversely affects an individual's quality of life. The purpose of this study was to develop a functional MRI protocol for mapping the function of ATL in healthy subjects, and to better understand the role of the ATL and other regions of the semantic system. Such a protocol may ultimately be used by surgeons to predict and reduce or prevent side effects of cognitive decline that occur after ATL resection in epilepsy patients. The aims were: (1) To study the ATL response to associations with abstract and concrete concepts and (2) To study the ATL response to names of people and places, and the information associated with these names. Our results indicated that ATL and inferior parietal areas are modulated by the amount of information associated with proper names. ATL is activated for abstract and concrete words relative to nonwords but is not modulated by associative measures. Angular and posterior cingulate gyri, on the other hand, are modulated by information associated with both common and proper names, underlining their role in semantic representations. A very high degree of overlap between person- and word-specific networks suggests that a common semantic system underlies both types of knowledge, rather than segregation of social and non-social knowledge. These results also demonstrate robust activation of ATL by proper and common names, and point to their potential use in mapping eloquent and functionally relevant cortex in epilepsy patients.