Author name cluster

Pieter B. de Best

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2 papers

1 author row

YNIMG Journal 2025 Journal Article

Cortical visual field representation and data integration following optic neuritis

Ruth Abulafia
Pieter B. de Best
Ayelet McKyton
Adi Vaknin-Dembinsky
Panayiota Petrou
Atira S. Bick
Netta Levin

Optic neuritis (ON) is an inflammatory, demyelinating optic neuropathy commonly associated with multiple sclerosis. Its clinical presentation typically includes monocular vision loss, with most visual functions recovering within several weeks. In addition to spontaneous remyelination, brain adaptation has been suggested to play a role in the recovery process. To further investigate this hypothesis, we examined cortical visual field representation and data integration during the first year following a first-ever ON episode. Eight ON participants and ten controls underwent fMRI scans under three viewing conditions: two monocular conditions (affected/fellow eye for ON; dominant/non-dominant eye for controls) and one binocular condition (both eyes open). For each condition, population receptive field (pRF) and connective field (CF) modeling were applied to assess spatial properties and sampling extent across the early visual cortical hierarchy (V1-V3). Consistent with previous studies, controls demonstrated an increase in average pRF and CF sizes along the visual hierarchy, with no significant differences between viewing conditions. In contrast, the ON group exhibited unique patterns. In the fellow eye condition, the typical pRF size increase along the visual hierarchy was absent, primarily due to reduced pRF sizes in V3. Additionally, in the affected eye, CF sizes were significantly larger than in the fellow eye. These modulations may reflect enhanced resolution for the unaffected eye and an increased extent of data processing when visual input is impaired (originating from the affected nerve). Therefore, we suggest that these cortical changes may be part of a spatial adaptation mechanism.

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YNICL Journal 2022 Journal Article

Structural changes to primary visual cortex in the congenital absence of cone input in achromatopsia

Barbara Molz
Anne Herbik
Heidi A. Baseler
Pieter B. de Best
Richard W. Vernon
Noa Raz
Andre D. Gouws
Khazar Ahmadi

Autosomal recessive Achromatopsia (ACHM) is a rare inherited disorder associated with dysfunctional cone photoreceptors resulting in a congenital absence of cone input to visual cortex. This might lead to distinct changes in cortical architecture with a negative impact on the success of gene augmentation therapies. To investigate the status of the visual cortex in these patients, we performed a multi-centre study focusing on the cortical structure of regions that normally receive predominantly cone input. Using high-resolution T1-weighted MRI scans and surface-based morphometry, we compared cortical thickness, surface area and grey matter volume in foveal, parafoveal and paracentral representations of primary visual cortex in 15 individuals with ACHM and 42 normally sighted, healthy controls (HC). In ACHM, surface area was reduced in all tested representations, while thickening of the cortex was found highly localized to the most central representation. These results were comparable to more widespread changes in brain structure reported in congenitally blind individuals, suggesting similar developmental processes, i.e., irrespective of the underlying cause and extent of vision loss. The cortical differences we report here could limit the success of treatment of ACHM in adulthood. Interventions earlier in life when cortical structure is not different from normal would likely offer better visual outcomes for those with ACHM.

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