title: The importance of premotor cortex for supporting speech production after left capsular-putaminal damage.
abstract: The left putamen is known to be important for speech production, but some patients with left putamen damage can produce speech remarkably well. We investigated the neural mechanisms that support this recovery by using a combination of techniques to identify the neural regions and pathways that compensate for loss of the left putamen during speech production. First, we used fMRI to identify the brain regions that were activated during reading aloud and picture naming in a patient with left putamen damage. This revealed that the patient had abnormally high activity in the left premotor cortex. Second, we used dynamic causal modeling of the patient's fMRI data to understand how this premotor activity influenced other speech production regions and whether the same neural pathway was used by our 24 neurologically normal control subjects. Third, we validated the compensatory relationship between putamen and premotor cortex by showing, in the control subjects, that lower connectivity through the putamen increased connectivity through premotor cortex. Finally, in a lesion-deficit analysis, we demonstrate the explanatory power of our fMRI results in new patients who had damage to the left putamen, left premotor cortex, or both. Those with damage to both had worse reading and naming scores. The results of our four-pronged approach therefore have clinical implications for predicting which patients are more or less likely to recover their speech after left putaminal damage.
authors.affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, United Kingdom m.seghier@ucl.ac.uk.
authors.forename: Mohamed L
authors.identifier: http://orcid.org/0000-0002-1146-8800
authors.initials: ML
authors.lastname: Seghier
authors.affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Juliana
authors.initials: J
authors.lastname: Bagdasaryan
authors.affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Dorit E
authors.initials: DE
authors.lastname: Jung
authors.affiliation: Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, United Kingdom.
authors.forename: Cathy J
authors.initials: CJ
authors.lastname: Price
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000502:physiology*; D011699:Putamen / Q000473:pathology* / Q000502:physiology*; D013060:Speech / Q000502:physiology*; D055815:Young Adult
keywords: Premotor cortex; putamen; reading words; recovery pathways; subcortical stroke