Cortical Visual Symptoms

Transcription

1 대한안신경의학회지 : 제 6 권 Supplement 2 ISSN: Jeong-Yoon Choi Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Korea Jeong-Yoon Choi. MD. PhD. Department of Neurology, Seoul National University Bundang Hospital Most lesions of the visual system from the retina to the striate cortex characteristically cause scotoma. Lesions of extrastriate cortex lead to very different types of deficits. They cause a loss of a specific type of visual function that often is neither localized nor limited to one part of the field. Copyright 2016 The Korean Society of Neuro-Ophthalmology S121

2 Choi JY Where (dorsal) system: project to PO association cortex Analyzing motion Analyzing spatial relationships between objects, & between the body & visual stimuli Akinetopsia; Simultanagnosia; Optic ataxia; Ocular motor apraxia; Asterognosis What (ventral) system: project to TO association cortex Analyzing form (colors, faces, letters, and other visual stimuli) Achromatopsia; (General) Visual agnosia; Prosopagnosia; Pure alexia; Topographagnosia Striate cortex (V1, layer 4) Medial superior temporal region First stage Motion-specific neurons Direction selective Retinotopic & small receptive field within contralateral visual space) Project to MT Second stage Integration of individual orthogonal components relayed from V1 Retinotopic & large receptive field within contralateral visual space Opponent suppression Surface segmentation Third stage Respond to the pattern of motion (expanding contraction - rotations) Craniotopic (navigation & motion of objects) Spatial awareness Pursuit eye motion Depth perception Structure from motion Striate cortex (V1, layer 4) Motion selective neurons Direction selective Retinotopic small receptive field within contralateral visual space Project to MT S122

3 Choi JY Middle temporal region Integration of individual orthogonal components relayed from V1 Retinotopic & large receptive field within contralateral visual space Opponent suppression Integration of individual orthogonal components relayed from V1 Surface segmentation Depth perception Structure from motion Opponent suppression Depth perception Structure from motion Medial superior temporal region Respond to the pattern of motion (expanding contraction - rotations) Craniotopic (navigation & motion of objects) Allocentric representation Spatial awareness Pursuit eye motion S123

4 Choi JY Medial superior temporal region Heading direction Medial superior temporal region Craniotopic reference Medial superior temporal region Allocentric representation Vestibular-Visual information about self motion - D/Dx object motion (visual) - Update spatial orientation Dorsal Visual System: Motion perception Akinetopsia insufficiency normal excess S124

5 Choi JY Akinetopsia Epileptic Kinetopsia (Cerebral macrokinetopsia) An exaggerated motion perception of retinal image motion A 38-year-old right-handed woman developed simple partial seizures 1 year before presentation. Her first seizure occurred while driving: she saw the cars in the lane coming toward her, moving from the left to the right side. Epileptic: ictal illusory motion perception Neurology A 33-year-old right-handed woman had had pharmacoresistant focal epilepsy since age 15 months. Her habitual seizures started at age 16 years, characterized by visual perception of stationary objects located on her right side shift to the center or to the left. Epileptic kinetopsia localizes to superior parietal lobule and intraparietal sulcus Neurology Epileptic Kinetopsia (Cerebral macrokinetopsia) An exaggerated motion perception of retinal image motion P1: When I saw a stationary target on a passage, all things look as those are. However, a man who walked on my left side appeared to sway extremely from side to side. P2: When the attacks started, the surrounding objects suddenly came up to me. At times, the attacks develop when I was walking along the street, and the walking people appeared moving faster. : Function and Disorders Cerebral macrokinetopsia: Exaggerated perception of retinal image motion J Neurol Sci Color perception & Achromatopsia Achromatopsia Patients with achromatopsia cannot name, point to, or match colors presented visually, but name the appropriate color for an object described verbally. What is the color of tomato?: Red (0) S125

6 Choi JY Associating symptoms Right side hemianopsia Alexia without agraphia Color agnosia (anomia) Patients cannot name color presented visually. Perception of color is preserved, so that the patients can match the color presented visually. Agnosia Agnosia: normal perception stripped of its meaning. Associative agnosia: pure form of agnosia without perceptual deficits Apperceptive agnosia: agnosia that may be attributed to impaired primary sensory modality. What is the color of tomato?: Red (0) (so D/Dx with anomia aphasia) Facial recognition Agnosia in facial recognition (Prosopagnosia) Fusiform face area Occipital face area Prosopagnosia is the inability to recognize faces that were either previously known to the patient or recently learned. To recognize people, those patients use other visual cues or auditory cues (clothes, voices, & etc). Face Face recognition (0) / Face belong to someone (X) Agnosia in facial recognition (Prosopagnosia) General visual agnosis (-) Preserved knowledge about biographic details of celebrities. Celebrities recognition by voice. Face recognition (X) + Voice recognition (X) + Reduced semantic memory about people Multimodal person sematic deficit (Anterior temporal lesion) Face recognition (X) + Voice recognition (0) + Preserved semantic memory Prosopagnosia Staring at familiar face + Naming difficulty - Prosopanomia Thanks for your attentions S126