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A Large Lateral Craniotomy Procedure for Mesoscale Wide-field Optical Imaging of Brain Activity
Published on: May 7, 2017
Training-induced cortical representation of a hemianopic hemifield
L Henriksson1, A Raninen, R Näsänen
1Advanced Magnetic Imaging Centre and Brain Research Unit of Low Temperature Laboratory, Helsinki University of Technology, Espoo, Finland. henriksson@neuro.hut.fi
Journal of Neurology, Neurosurgery, and Psychiatry
|September 19, 2006
Summary
Intensive flicker training in a stroke patient with homonymous hemianopia reorganized visual processing. The intact hemisphere took over processing for the blind visual field, showing cortical plasticity in adults.
Area of Science:
- Neuroscience
- Neuroplasticity
- Visual Rehabilitation
Background:
- Homonymous hemianopia (HH) patients retain some visual sensitivity in their blind field.
- Extrastriate cortical areas are implicated in residual vision for HH patients.
- Visual training outcomes for HH are inconsistent.
Observation:
- A 61-year-old patient with HH underwent flicker stimulation training 22 months post-stroke.
- Magnetoencephalography (MEG) tracked functional changes during training.
- Functional magnetic resonance imaging (fMRI) assessed cortical organization post-training.
Findings:
- Post-training, both hemifields' visual information was processed in the intact hemisphere.
- fMRI revealed representations of both blind and normal hemifields within the intact hemisphere's visual areas.
- These areas included V5, superior temporal sulcus region, and retinotopic areas V1, V2, V3, and V3a.
Implications:
- Intensive hemifield training can induce significant cortical reorganization in adult stroke survivors.
- This case demonstrates ipsilateral visual field representation in multiple cortical areas, including primary visual cortex (V1).
- Findings suggest potential for visual rehabilitation strategies targeting cortical plasticity in hemianopia.
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