Podcast
Questions and Answers
What does the right visual pathway primarily involve in terms of visual information processing?
What does the right visual pathway primarily involve in terms of visual information processing?
Which of the following accurately describes the crossing of axons for the left eye's visual pathway?
Which of the following accurately describes the crossing of axons for the left eye's visual pathway?
What is known as homonymous hemianopsia?
What is known as homonymous hemianopsia?
What stream is responsible for identifying the 'what' aspect of visual information?
What stream is responsible for identifying the 'what' aspect of visual information?
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What characterizes a primary visual cortex in each occipital lobe?
What characterizes a primary visual cortex in each occipital lobe?
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Which visual field loss condition occurs with damage to an occipital lobe?
Which visual field loss condition occurs with damage to an occipital lobe?
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What kind of visual information processing occurs in the right temporal lobe?
What kind of visual information processing occurs in the right temporal lobe?
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Which statement about the visual pathways is true?
Which statement about the visual pathways is true?
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What is one of the most common symptoms of a posterior stroke?
What is one of the most common symptoms of a posterior stroke?
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What percentage of cerebral strokes occur in the cerebral posterior region?
What percentage of cerebral strokes occur in the cerebral posterior region?
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In patients with visual field cuts, what is their typical awareness regarding the condition?
In patients with visual field cuts, what is their typical awareness regarding the condition?
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What condition is characterized by problems with object identification and spatial navigation often starting from the occipital lobe?
What condition is characterized by problems with object identification and spatial navigation often starting from the occipital lobe?
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Which part of the brain processes signals from the right visual field of each eye?
Which part of the brain processes signals from the right visual field of each eye?
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Which of the following difficulties is NOT typically associated with posterior cortical atrophy?
Which of the following difficulties is NOT typically associated with posterior cortical atrophy?
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What phenomenon describes the way light waves interact with the lens before entering the retina?
What phenomenon describes the way light waves interact with the lens before entering the retina?
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What is a common misconception about strokes affecting the posterior cortical areas?
What is a common misconception about strokes affecting the posterior cortical areas?
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What is the main characteristic of homonymous quadrantanopsia?
What is the main characteristic of homonymous quadrantanopsia?
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In visual anosognosia, individuals may demonstrate which behavior?
In visual anosognosia, individuals may demonstrate which behavior?
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Which ability is primarily affected by impairments in visuospatial perception?
Which ability is primarily affected by impairments in visuospatial perception?
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What is a common outcome of damage to the posterior circulation that affects speech?
What is a common outcome of damage to the posterior circulation that affects speech?
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Which condition is characterized by damage to the primary visual cortex, leading to inability to perceive images?
Which condition is characterized by damage to the primary visual cortex, leading to inability to perceive images?
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What aspect of perception remains intact in cortical blindness?
What aspect of perception remains intact in cortical blindness?
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Which of the following best describes prosopagnosia?
Which of the following best describes prosopagnosia?
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What occurs as a result of damage to the ventral pathway?
What occurs as a result of damage to the ventral pathway?
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Study Notes
Posterior Cortical Areas
- Posterior cortical areas share a blood supply from the posterior cerebral artery, including the occipital lobe, posterior parietal lobe, and inferior/posterior temporal lobe.
- A stroke affecting these areas can cause various symptoms due to the shared blood supply.
Posterior Stroke Symptoms (Video)
- Visual field defects are a common symptom of a posterior stroke.
Posterior Stroke Diseases
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Strokes:
- 15-20% of all cerebral strokes occur in the posterior region.
- Often related to diabetes.
- Frequently present with visual field cuts and ataxia.
- Initial misdiagnosis is common as these strokes don't typically lead to language problems or hemiparesis.
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Degenerative Diseases:
- Less likely to be affected by degenerative diseases (e.g., dementia) but might be impacted.
- Posterior cortical atrophy in people aged 50-65.
- Starts with occipital and posterior temporal lobes.
- Symptoms include dementia (like Alzheimer's and Lewy bodies dementia).
- Characterized by problems with object identification, driving, walking on uneven surfaces, localizing objects, navigating, gauging distance/depth, and spatio-motor skills.
Visual Field Cuts
- Visual field cuts affect reading, writing, communication, and visual information like gestures.
- Patients are usually aware of the cuts and compensate by moving their head or eyes.
Visual Pathways (Page 2)
- Visual Fields: Phototransduction in the retina, contralateral sensorimotor control, and visual field testing. The left occipital lobe processes signals from the right visual field of each eye, and the right occipital lobe processes signals from the left visual field of each eye.
- Visual Pathways: Light waves hit the eyeballs, then are refracted by the lens and the retinal image is inverted. Information from the left visual field projects to the right side of the retina and vice-versa.
- Right Visual Pathway: Starts on the left side of each eyeball and ends in the left occipital lobe. Information from the right eye travels to the left occipital lobe. Axons don't cross the optic chiasm in this case. Information from the left eye needs to cross the optic chiasm.
- Left Visual Pathway: Starts on the right side of each eyeball and ends in the right occipital lobe. The information from the left eye goes to the right occipital lobe, and the optic chiasm isn't crossed. Axons from the right eye also go to the right occipital lobe, but the optic chiasm is crossed in this case.
Occipital Lobe & Visual Streams (Page 3)
- Homonymous Visual Field Cut: Vision loss on the same visual field (left or right) in both eyes.
- Types include homonymous hemianopsia (loss of half a visual field) and homonymous quadrantanopsia (loss of a quarter of a visual field).
- Cortical Blindness: Bilateral damage to the primary visual cortex resulting in the inability to perceive images although light and dark can still be perceived.
Visual Anosognosia (Anton's Syndrome)
- A condition where people with cortical blindness lack awareness of the blindness. They may confabulate (falsely describe what they "see").
Visuospatial Perception (Page 4)
- Ability to locate and discriminate objects, judge distance, orient the body in space, and perceive dimensions.
- Impairments can include distortions, trouble with reading, writing, and judging distances.
Visuospatial Construction (Page 4)
- Ability to draw, build, copy.
Spatial Cognition (Page 4)
- Ability to recognize shapes, use mental rotation, navigate mazes, and spatial organization.
Speech Disorders (Page 4)
- Posterior circulation stroke can cause dysarthria (difficulty with articulation) if corticobulbar nerve tracts are damaged.
Language Disorders (Page 4)
- Posterior damage can lead to alexia (reading problems) and agraphia (writing problems).
Swallowing Disorders (Page 4)
- Dysphagia (difficulty swallowing) rarely occurs with damage to the posterior hemispheres due to the absence of necessary motor regions or pathways.
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Description
Explore the impact of strokes on posterior cortical areas, including the occipital lobe and posterior parietal lobe. This quiz covers common symptoms resulting from posterior strokes and their link to degenerative diseases. Test your understanding of how these areas are affected and the resulting clinical presentations.
