Summary
This thesis investigates how early visual processing pathways — particularly the magnocellular and S-cone chromatic pathways — are altered by Parkinson's disease and represented in healthy human visual cortex, using electrophysiology, fMRI, and psychophysics. Findings suggest that visual pathway biomarkers may help classify neurodegenerative disease states, and that temporal contrast sensitivity varies across visual space in ways relevant to understanding lighting perception in clinical populations.
Key Findings
- Machine learning classifiers applied to multivariate visual response profiles from Drosophila and rodent Parkinson's disease models could accurately classify animals into their correct disease class.
- Temporal contrast sensitivity differed as a function of visual space, with peripherally tuned voxels in early visual areas showing increased contrast sensitivity at high temporal frequencies.
- Excitotoxicity was identified as a pathological mechanism in the visual system of Drosophila Parkinson's disease models.
- 7T fMRI investigation of S-cone population receptive field (pRF) sizes failed to replicate the expected eccentricity-dependent increase in pRF size, indicating methodological complications.
Categories
Eye Health & Vision: Investigates low-level visual processing pathways (magnocellular and S-cone chromatic) and how they are compromised in neurological disease, particularly Parkinson's disease.
The Science of Light: Examines spectral sensitivity and photoreceptor pathway biology including S-cone and magnocellular pathways using fMRI and electrophysiology.
Dementia & Elder Care: Uses animal models of Parkinson's disease to identify pathological visual processing mechanisms relevant to neurodegenerative conditions.
Author(s)
MM Himmelberg
Publication Year
2019
Related Publications
Eye Health & Vision
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Genetic reactivation of cone photoreceptors restores visual responses in retinitis pigmentosa
- Melanopsin and rod–cone photoreceptors play different roles in mediating pupillary light responses during exposure to continuous light in humans
- Characteristic patterns of dendritic remodeling in early-stage glaucoma: evidence from genetically identified retinal ganglion cell types
- Intrinsically photosensitive melanopsin retinal ganglion cell contributions to the pupillary light reflex and circadian rhythm
The Science of Light
- Phototransduction by retinal ganglion cells that set the circadian clock
- Color appearance models
- The mammalian circadian timing system: organization and coordination of central and peripheral clocks
- Diminished pupillary light reflex at high irradiances in melanopsin-knockout mice
- Melanopsin is required for non-image-forming photic responses in blind mice
Dementia & Elder Care
- Light therapy and Alzheimer's disease and related dementia: past, present, and future
- New strategies for neuroprotection in glaucoma, a disease that affects the central nervous system
- Sleep and circadian rhythms in Parkinson's disease and preclinical models
- Chronobioengineering indoor lighting to enhance facilities for ageing and Alzheimer's disorder
- The clock is ticking. Ageing of the circadian system: from physiology to cell cycle