Pathways of interhemispheric transfer in normals and in a split-brain subject. A positron emission tomography study

C. A. Marzi, D. Perani, G. Tassinari, A. Colleluori, A. Maravita, C. Miniussi, E. Paulesu, P. Scifo, F. Fazio

Research output: Contribution to journalArticlepeer-review

Abstract

We studied with PET the intra- and interhemispheric pathways subserving a simple, speeded-up visuomotor task. Six normal subjects and one patient with a complete section of the corpus callosum (M.E.) underwent regional cerebral blood flow (rCBF) measurements under conditions of lateralized tachistoscopic visual presentations in a simple manual reaction time paradigm. Confirming previous behavioural findings, we found that on average crossed hand and/or hemifield conditions, i.e. those requiring an interhemispheric transfer of information, yielded a longer RT than uncrossed conditions. This difference (0.7 ms) was dramatically larger (45.6 ms) in the callosum-sectioned patient M.E. In normal subjects the cortical areas selectively activated in uncrossed and crossed conditions were different. In the former condition, most activation foci were anterior to the ventral anterior commissure (VAC) plane, whereas in the latter there was a prevalent parietal and occipital activation. This shows that a simple model in which the cortical visuo-motor pathways are similar in the intra- and the interhemispheric condition, with an extra callosal route for the latter, is too simplistic. Furthermore, these results suggest that the bulk of visuomotor interhemispheric transfer takes place through the widespread callosal fibres interconnecting the parietal cortices of the two hemispheres. The pattern of activation in the two crossing conditions was markedly different in M.E., in whom interhemispheric transfer might take place via his intact anterior commissure or subcortical commissures.

Original languageEnglish
Pages (from-to)451-458
Number of pages8
JournalExperimental Brain Research
Volume126
Issue number4
DOIs
Publication statusPublished - 1999

Keywords

  • Corpus callosum
  • Human
  • Interhemispheric transfer
  • Positron emission tomography
  • Split brain

ASJC Scopus subject areas

  • Neuroscience(all)

Fingerprint Dive into the research topics of 'Pathways of interhemispheric transfer in normals and in a split-brain subject. A positron emission tomography study'. Together they form a unique fingerprint.

Cite this