title: Topographical gradients of semantics and phonology revealed by temporal lobe stimulation.
abstract: Word retrieval is a fundamental component of oral communication, and it is well established that this function is supported by left temporal cortex. Nevertheless, the specific temporal areas mediating word retrieval and the particular linguistic processes these regions support have not been well delineated. Toward this end, we analyzed over 1000 naming errors induced by left temporal cortical stimulation in epilepsy surgery patients. Errors were primarily semantic (lemon → "pear"), phonological (horn → "corn"), non-responses, and delayed responses (correct responses after a delay), and each error type appeared predominantly in a specific region: semantic errors in mid-middle temporal gyrus (TG), phonological errors and delayed responses in middle and posterior superior TG, and non-responses in anterior inferior TG. To the extent that semantic errors, phonological errors and delayed responses reflect disruptions in different processes, our results imply topographical specialization of semantic and phonological processing. Specifically, results revealed an inferior-to-superior gradient, with more superior regions associated with phonological processing. Further, errors were increasingly semantically related to targets toward posterior temporal cortex. We speculate that detailed semantic input is needed to support phonological retrieval, and thus, the specificity of semantic input increases progressively toward posterior temporal regions implicated in phonological processing. Hum Brain Mapp 38:688-703, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Psychology, The New School, New York.
authors.forename: Michele
authors.initials: M
authors.lastname: Miozzo
authors.affiliation: Department of Neurology, Columbia University Medical Center, New York.
authors.forename: Alicia C
authors.initials: AC
authors.lastname: Williams
authors.affiliation: Department of Neurology, Columbia University Medical Center, New York.
authors.forename: Guy M
authors.initials: GM
authors.lastname: McKhann
authors.affiliation: Department of Neurology, Columbia University Medical Center, New York.
authors.forename: Marla J
authors.initials: MJ
authors.lastname: Hamberger
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D004566:Electrodes; D004827:Epilepsy / Q000000981:diagnostic imaging / Q000601:surgery; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010700:Phonetics; D010775:Photic Stimulation; D012660:Semantics; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000503:physiopathology*; D055815:Young Adult
keywords: cortical stimulation; epilepsy; language production; lexical access; naming errors