An 80-year-old right-handed man suddenly became impossible to recognize any color 7 years prior to admission. He complained that everything looked like of the same color, monochromatic. On admission, he could not discriminate any color and any familial face. Left homonymous hemianopsia associated with right lower partial visual filed defect was observed, but visual acuity of both eyes was well preserved. Visual-visual color tasks (Ishihara, matching, Hue test, Panel-D15) disclosed the disturbances in color perception. However, he could roughly distinguished red or brown from the other colors. The color test was also impaired regarding the visual-verbal color tasks (naming, pointing). However, verbal description of the color concept, which was shown by the verbal-verbal color tasks, was well preserved. In addition, we observed left hemispatial neglect, disturbance of face recognition and topographical disorientation. MRI revealed old hemorrhagic infarcts in the bilateral occipital and temporal lobes, including the bilateral lateral and medial occipito-temporal gyri. Disturbance of color recognition in this case was diagnosed as cerebral achromatopsia on the basis of clinical characteristics and MRI findings. This is the first case of cerebral achromatopsia of which lesions were detected by MRI in detail.
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Am J Ophthalmol Case Rep
March 2025
Texas A and M School of Medicine, Bryan, TX, USA.
Brain
January 2025
Faculty of Social and Behavioural Sciences, University of Amsterdam, 1001 NK, Amsterdam, The Netherlands.
Mid-level visual processing represents a crucial stage between basic sensory input and higher-level object recognition. The conventional model posits that fundamental visual qualities like color and motion are processed in specialized, retinotopic brain regions (e.g.
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December 2024
Affiliated Mental Health Center (ECNU), School of Psychology and Cognitive Science, East China Normal University, Shanghai, China.
The assessment of color vision is crucial in both fundamental visual research and clinical diagnosis. However, existing tools for color vision assessment are limited by various factors. This study introduces a novel, efficient method for color vision assessment, which is based on a continuous motion tracking task and a Kalman filter model.
View Article and Find Full Text PDFBrain Res Bull
September 2024
UCL Institute of Cognitive Neuroscience, University College London, UK; The Wellcome Centre for Human Neuroimaging, University College London, UK.
Achromatopsia is an inherited retinal disease that affects 1 in 30,000-50,000 individuals and is characterised by an absence of functioning cone photoreceptors from birth. This results in severely reduced visual acuity, no colour vision, marked sensitivity to light and involuntary oscillations of the eyes (nystagmus). In most cases, a single gene mutation prevents normal development of cone photoreceptors, with mutations in the CNGB3 or CNGA3 gene being responsible for ∼80 % of all patients with achromatopsia.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2024
School of Electronic Science and Engineering, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China.
The human brain efficiently processes only a fraction of visual information, a phenomenon termed attentional control, resulting in energy savings and heightened adaptability. Translating this mechanism into artificial visual neurons holds promise for constructing energy-efficient, bioinspired visual systems. Here, we propose a self-rectifying artificial visual neuron (SEVN) based on a NiO/GaO bipolar heterojunction with attentional control on patterns with a target color.
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