Macaque Area V2/V3 Reorganization Following Homonymous Retinal Lesions.

In the adult visual system, topographic reorganization of the primary visual cortex (V1) after retinal lesions has been extensively investigated. In contrast, the plasticity of higher order extrastriate areas following retinal lesions is less well studied. Here, we used fMRI to study reorganization of visual areas V2/V3 following the induction of permanent, binocular, homonymous retinal lesions in 4 adult macaque monkeys.

Population receptive field analysis of the primary visual cortex complements perimetry in patients with homonymous visual field defects.

Injury to the primary visual cortex (V1) typically leads to loss of conscious vision in the corresponding, homonymous region of the contralateral visual hemifield (scotoma). Several studies suggest that V1 is highly plastic after injury to the visual pathways, whereas others have called this conclusion into question. We used functional magnetic resonance imaging (fMRI) to measure area V1 population receptive field (pRF) properties in five patients with partial or complete quadrantic visual field loss as a result of partial V1+ or optic radiation lesions.

Visual cortex organisation in a macaque monkey with macular degeneration.

The visual field is retinotopically represented in early visual areas. It has been suggested that when adult primary visual cortex (V1) is deprived of normal retinal input it is capable of large-scale reorganisation, with neurons inside the lesion projection zone (LPZ) being visually driven by inputs from intact retinal regions. Early functional magnetic resonance imaging (fMRI) studies in humans with macular degeneration (MD) report > 1 cm spread of activity inside the LPZ border, whereas recent results report no shift of the LPZ border.

Detailed functional and structural characterization of a macular lesion in a rhesus macaque.

Purpose: Animal models are powerful tools to broaden our understanding of disease mechanisms and to develop future treatment strategies. Here we present detailed structural and functional findings of a rhesus macaque suffering from a naturally occurring bilateral macular dystrophy (BMD), partial optic atrophy and corresponding reduction of central V1 signals in visual fMRI experiments when compared to data in a healthy macaque (CTRL) of similar age.

Methods: Retinal imaging included infrared and autofluorescence recordings, fluorescein and indocyanine green angiography and spectral domain optical coherence tomography (OCT) on the Spectralis HRA + OCT platform.