An fMRI investigation of the cortical network underlying detection and categorization abilities in hemianopic patients

Céline Perez, Carole Peyrin, Céline Cavézian, Olivier Coubard, Florent Caetta, Noa Raz, Netta Levin, Gaëlle Doucet, Frédéric Andersson, Michaël Obadia, Olivier Gout, Françoise Héran, Julien Savatovsky, Sylvie Chokron

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

The current study aims to investigate visual scene perception and its neuro-anatomical correlates for stimuli presented in the central visual field of patients with homonymous hemianopia, and thereby to assess the effect of a right or a left occipital lesion on brain reorganization. Fourteen healthy participants, three left brain damaged (LBD) patients with right homonymous hemianopia and five right brain damaged (RBD) patients with left homonymous hemianopia performed a visual detection task (i.e. "Is there an image on the screen?") and a categorization task (i.e. "Is it an image of a highway or a city?") during a block-designed functional magnetic resonance imaging recording session. Cerebral activity analyses of the posterior areas - the occipital lobe in particular - highlighted bi-hemispheric activation during the detection task but more lateralized, left occipital lobe activation during the categorization task in healthy participants. Conversely, in patients, the same network of activity was observed in both tasks. However, LBD patients showed a predominant activation in their right hemisphere (occipital lobe and posterior temporal areas) whereas RBD patients showed a more bilateral activation (in the occipital lobes). Overall, our preliminary findings suggest a specific pattern of cerebral activation depending on the task instruction in healthy participants and cerebral reorganization of the posterior areas following brain injury in hemianopic patients which could depend upon the side of the occipital lesion.

Original languageEnglish (US)
Pages (from-to)264-277
Number of pages14
JournalBrain Topography
Volume26
Issue number2
DOIs
StatePublished - Apr 2013

Keywords

  • Categorization
  • Detection
  • Hemianopia
  • Natural scenes
  • fMRI

ASJC Scopus subject areas

  • Anatomy
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging
  • Neurology
  • Clinical Neurology

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