Magnetoencephalographic Studies of Language Reorganization After Cerebral Insult

Co-registered MEG-MRI scans (the left hemisphere is on the left side of the image) for (A) a patient with apparent bilateral language representation preoperatively (upper row) and a shift of lateralization to the right hemisphere after anterior temporal lobectomy (lower row) and (B) a patient with left hemisphere representation preoperatively (upper row) who showed an intrahemispheric shift postoperatively (lower row). Green squares show the activity sources observed during the first session and red squares show activity observed during the second session. The region of spatial overlap between the 2 maps within a given hemisphere is marked by a white circle. From Pataraia et al.¹⁶ Reprinted with permission.

Co-registered MEG-MRI scans (the left hemisphere is on the left side of the image) for (A) an epilepsy patients with left mesial temporal sclerosis and apparent bilateral language representation and (B) a patient with a pilocystic astrocytoma in the left supramarginal gyrus showing an atypical localization of receptive language in left hemisphere. Green squares show the activity sources observed during the first session and red squares show activity observed during the second session. The region of spatial overlap between the 2 maps within a given hemisphere is marked by a white circle. From Pataraia et al.²⁵ Reprinted with permission.

Co-registered MEG-MRI scans (the left hemisphere is on the left side of the image) for (A) a control subject and (B) a subject with a history of left-hemisphere stroke. From Breier et al.²⁴ Reprinted with permission.

Mean number of sources in each of the consecutive 50-ms epochs for (A) controls and (B) patients within left (solid lines) and right (dashed lines) STG. The arrow indicates the approximate time of onset of late, language-specific activity. Abbreviations: LH, left hemisphere; RH, right hemisphere. Reprinted with permission.²⁴