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Questions and Answers
Hemianopia is a type of cortical blindness that affects a quarter of the visual field.
Hemianopia is a type of cortical blindness that affects a quarter of the visual field.
False
A person with achromatopsia sees the world in shades of color, but not as vividly as people with normal color vision.
A person with achromatopsia sees the world in shades of color, but not as vividly as people with normal color vision.
False
Blindsight is the ability to consciously perceive visual stimuli, but not respond to them.
Blindsight is the ability to consciously perceive visual stimuli, but not respond to them.
False
Quadrantanopia is a type of cortical blindness that affects the entire visual field.
Quadrantanopia is a type of cortical blindness that affects the entire visual field.
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V5 (or MT) is a region of extrastriate cortex associated with color perception.
V5 (or MT) is a region of extrastriate cortex associated with color perception.
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A person with akinetopsia has difficulty perceiving colors due to damage to V4.
A person with akinetopsia has difficulty perceiving colors due to damage to V4.
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Apperceptive agnosia is a failure to recognize objects due to a deficit at the level of semantic memory.
Apperceptive agnosia is a failure to recognize objects due to a deficit at the level of semantic memory.
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The extrastriate body area (EBA) is an area of the brain that responds to scenes more than objects.
The extrastriate body area (EBA) is an area of the brain that responds to scenes more than objects.
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The case of HJA is an example of associative agnosia.
The case of HJA is an example of associative agnosia.
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The fusiform face area (FFA) is an area in the inferior temporal lobes that responds to objects other than faces.
The fusiform face area (FFA) is an area in the inferior temporal lobes that responds to objects other than faces.
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Agnosia is a failure in object recognition due to a deficit at the level of structural descriptions.
Agnosia is a failure in object recognition due to a deficit at the level of structural descriptions.
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Categorical perception refers to the notion that the brain represents different categories in the same way.
Categorical perception refers to the notion that the brain represents different categories in the same way.
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The parahippocampal place area (PPA) is an area of the brain that responds to objects more than scenes.
The parahippocampal place area (PPA) is an area of the brain that responds to objects more than scenes.
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Prosopagnosia is the inability to recognize previously unfamiliar faces.
Prosopagnosia is the inability to recognize previously unfamiliar faces.
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The brain merely interprets the real image from the eyes without any active construction of the visual representation.
The brain merely interprets the real image from the eyes without any active construction of the visual representation.
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Rod cells are specialized for high intensity of light and color information.
Rod cells are specialized for high intensity of light and color information.
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The fovea is made up of both rod and cone cells.
The fovea is made up of both rod and cone cells.
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The optic nerve is responsible for transmitting visual information from the eye to the brain.
The optic nerve is responsible for transmitting visual information from the eye to the brain.
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Simple cells in the primary visual cortex respond to movement and orientation.
Simple cells in the primary visual cortex respond to movement and orientation.
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Hypercomplex cells are found within the primary visual cortex (V1).
Hypercomplex cells are found within the primary visual cortex (V1).
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There are only two pathways in the visual system.
There are only two pathways in the visual system.
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The primary visual cortex is responsible for transmitting visual information to the suprachiasmatic nucleus in the hypothalamus.
The primary visual cortex is responsible for transmitting visual information to the suprachiasmatic nucleus in the hypothalamus.
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Neurons receive information through the axon.
Neurons receive information through the axon.
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The presynaptic neuron is the information receiver.
The presynaptic neuron is the information receiver.
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Lateral refers to the central regions of the brain.
Lateral refers to the central regions of the brain.
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Gray matter consists of axons and glia.
Gray matter consists of axons and glia.
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The subcortex is a part of the cerebral cortex.
The subcortex is a part of the cerebral cortex.
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The basal ganglia is involved in emotion regulation.
The basal ganglia is involved in emotion regulation.
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The thalamus and hypothalamus are part of the limbic system.
The thalamus and hypothalamus are part of the limbic system.
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The midbrain and hindbrain are part of the forebrain.
The midbrain and hindbrain are part of the forebrain.
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Study Notes
Sensation & Perception
- Sensation: Effects of stimulus on sensory organs
- Perception: Interpretation of stimulus based on prior experience
- The brain actively constructs the visual representation of the world
From Eye to Brain
- Rod cells: Specialized for low intensity of light and movement
- Cone cells: Specialized for high intensity of light and color information
- Fovea: Entirely made of cones, responsible for visual acuity
- Blind spot: Where the optic nerve leaves the eye
Geniculostriate Pathway
- Optic nerve → Optic chiasm → Optic tract → Lateral Geniculate Nucleus (LGN) → Primary visual cortex (V1)
Primary Visual Cortex (V1)
- Located in the occipital lobe, responsible for visual processing
- V1 is the first stage of processing in the cortex
- Simple cells: Respond to particular orientation and single points of light
- Complex cells: Combination of simple cells, larger receptive fields, respond to movement of orientation, do not respond to single points of light
- Hypercomplex cells: Just outside V1, built from responses of complex cells, respond to orientation and length
Cortical & Non-Cortical Routes
- Geniculostriate pathway is the best understood and makes the largest contribution to human visual perception
- Other routes are evolutionary older
- Pathway to suprachiasmatic nucleus in the hypothalamus provides information about time of day
- Pathways via superior colliculus and inferior pulvinar are important for orienting stimuli
Problems with Primary Visual Cortex
- Retinotopic organization: Layout of the receptive fields of neurons in V1 reflect the spatial organization of the retina
- Hemianopia: Cortical blindness restricted to one half of the visual field
- Quadrantanopia: Cortical blindness restricted to a quarter of the visual field
- Scotoma: A small region of cortical blindness
Blindsight
- Inability to report perceiving visual stimulus even though performance suggests otherwise
- Case of DB: Reported not seeing stimuli but oriented his eyes correctly toward stimuli
Extrastriate Areas in Vision
- V4: Associated with color perception and color constancy
- Achromatopsia: A failure to perceive color due to damage to V4
- V5 (or MT): Associated with motion perception
- Akinetopsia: A failure to perceive visual motion due to damage to V5
Dual Stream Visual Processing
- No specific information provided
Object Recognition
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- Perception of basic elements (e.g., edges of various lengths, contrasts & orientations)
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- Grouping physical elements (depth cues and divide surfaces)
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- The viewer-centered description is then matched onto stored 3D descriptions of the structure of objects
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- Meaning is attributed to the stimulus
Agnosia
- Failure in object recognition
- Apperceptive agnosia: A failure to recognize objects due to a deficit at the level of object perception
- Associative agnosia: A failure to recognize objects due to a deficit at the level of semantic memory
- Case of HJA: Seeing the part but not the whole, impaired at deciding if objects are real or made up and naming objects
Categorical Perception
- Category specificity: The brain represents different categories in different ways (and/or different regions)
- Parahippocampal place area (PPA): Area of the brain that responds to scenes more than objects
- The extrastriate body area (EBA): Area of the brain that responds to the human body more than to faces, scenes or objects
Face Recognition
- Fusiform face area (FFA): An area in the inferior temporal lobes that responds more to faces than other visual objects
- Prosopagnosia: Inability to recognize previously familiar faces
Introducing the Brain
- Neurons are cells that make up the nervous system, consisting of a cell body (soma), dendrites, and axon.
- The cell body contains the nucleus and organelles.
- Dendrites receive information, while the axon sends information.
Neural Communication
- Terminal buttons of a neuron and dendrites of another neuron communicate through a small gap called a synapse.
- Presynaptic neuron is the information giver, while postsynaptic neuron is the information receiver.
- Action potential electrically charges the presynaptic neuron, inducing the release of informative chemicals called neurotransmitters.
Terms of Directional References
- Lateral: refers to the outer regions of the brain.
- Medial: refers to the central regions of the brain.
Gross Organization of the Brain
- Gray matter consists of cell bodies.
- White matter consists of axons and glia (support cells involved in tissue repair and myelin formation).
Cerebral Cortex
- Folded sheets of gray matter.
- Raised surfaces are called gyri (gyrus).
- Folds are called sulci (sulcus).
- The folded structure helps to increase area/volume ratio (efficiency in packaging of the brain).
4 Main Parts of the Cerebral Cortex
- No specific information provided about the 4 main parts.
Subcortex
- Lies under the white matter.
- Consists of a gray matter collection.
- Includes basal ganglia, limbic system, thalamus, and hypothalamus.
Basal Ganglia
- Responsible for motor control and skill learning.
- Disorders associated with poverty or excess of movement (e.g., Parkinson's and Huntington's).
Limbic System
- No specific information provided about the limbic system.
Diencephalon
- Includes thalamus and hypothalamus.
Midbrain and Hindbrain
- No specific information provided about midbrain and hindbrain.
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Description
This quiz covers the basics of vision and perception, including sensation and perception, the role of the brain in constructing visual representation, and the functions of rod and cone cells.
