Visual Processing (Higher Centres) Flashcards
Define
Ablation
the surgical removal of body tissue.
Define
Area V1
the first stage of cortical processing of visual information. It contains a complete map of the visual field covered by the eyes
Define
Brain imaging
the use of various techniques to either directly or indirectly image the structure, function, or pharmacology of the nervous system
Define
Contralateral eye
the eye ball which is on the opposite side of the body of some other item of construction
Define
Cortical magnification
describes how many neurons in an area of the visual cortex are ‘responsible’ for processing a stimulus of a given size, as a function of visual field location
Define
Distributed representation
describes the same data features across multiple scalable and interdependent layers. Each layer defines the information with the same level of accuracy, but adjusted for the level of scale
Define
Dorsal pathway
a pathway that carries visual information from the primary visual cortex to the parietal lobe. According to one widely-accepted hypothesis, it carries information related to movement and spatial relationships between objects in the visual field. It is sometimes called the “where” pathway
Define
Double dissociations
two related mental processes are shown to function independently of each other
Define
Expertise hypothesis
suggests the mechanisms involved in face processing are also engaged by objects with high within-class similarity for which people have become experts at rapid individuation
Define
Extrastriate body area (EBA)
a subpart of the extrastriate visual cortex involved in the visual perception of human body and body parts, akin in its respective domain to the fusiform face area, involved in the perception of human faces
Define
Functional magnetic resonance imaging (fMRI)
a device that measures brain activity by detecting changes associated with blood flow
Define
Fusiform face area (FFA)
a part of the human visual system that is specialized for facial recognition. It is located in the Inferior temporal cortex (IT)
Define
Hippocampus
the elongated ridges on the floor of each lateral ventricle of the brain, thought to be the centre of emotion, memory, and the autonomic nervous system.
Define
How pathway
Also known as the parietal stream or the “where” stream, this pathway stretches from the primary visual cortex (V1) in the occipital lobe forward into the parietal lobe. It is interconnected with the parallel ventral stream (the “what” stream) which runs downward from V1 into the temporal lobe
Define
Hypercolumn
a 1 mm block of V1 containing both the ocular dominance and orientation columns for a particular region in visual space
Define
Ipsilateral eye
the eye located on the same side of the body as another structure or object
Define
Landmark discrimination problem
the behavioral task used in Ungerleider and Mishkin’s experiement in which they provided evidence for the dorsal, or where, visual processing stream
Define
Lateral occipital complex (LOC)
a large cortical region that appears to play a central role in object recognition
Define
Location columns
columns of the visual cortex that contain information from receptive fields at the same location on the retina
Define
M-ganglion cell
cells project to the magnocellular layers of the lateral geniculate nucleus
Define
Magnetic resonance imaging (MRI)
a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body
Define
Mind-body problem
a debate concerning the relationship between thought and consciousness in the human mind, and the brain as part of the physical body
Define
Modularity
the idea that there are self-contained areas in the brain that store mental processes such as the “lower level” reflexes
Define
Modules
functionally specialized cognitive systems that are domain-specific and may also contain innate knowledge about the class of information processed
Define
Neuropsychology
a branch of psychology that aims to study the relationships between the brain and behaviour
Define
Object discrimination problem
the behavioral task used in ungerleider and mishkins experiment in which they provided evidence for the ventral, or what, visual processing stream
Define
Ocular dominance columns
Columns in the visual cortex that respond preferentially to one eye
Define
Orientation columns
organized regions of neurons that are excited by visual line stimuli of varying angles. These columns are located in the primary visual cortex (V1) and span multiple cortical layers
Define
P-ganglion cell
cells project to the parvocellular layers of the lateral geniculate nucleus
Define
Parahippocampal place area (PPA)
a region in the human collateral sulcus that responds more strongly to visual scenes (e.g. images of landscapes or cityscapes) than to other visual stimuli
Define
Prosopagnosia
a neurological condition characterized by the inability to recognize the faces of familiar people
Define
Retinotopic map
the point-by-point representation of the retinal surface in another structure in the visual system, such as the striate cortex
Define
Spatial organisation
an aspect of spatial perception and concerns the perception of spatial relationships
Define
Ventral pathway
a pathway that carries visual information from the primary visual cortex to the temporal lobe. According to one widely-accepted hypothesis, it carries information related to object form and recognition
Define
What pathway
also known as the ventral stream, it leads to the temporal lobe, which is involved with object and visual identification and recognition
Define
Where pathway
Also known as the parietal stream or the “how” stream, this pathway stretches from the primary visual cortex (V1) in the occipital lobe forward into the parietal lobe. It is interconnected with the parallel ventral stream (the “what” stream) which runs downward from V1 into the temporal lobe
Definition
the surgical removal of body tissue.
Ablation
Definition
the first stage of cortical processing of visual information. It contains a complete map of the visual field covered by the eyes
Area V1
Definition
the use of various techniques to either directly or indirectly image the structure, function, or pharmacology of the nervous system
Brain imaging
Definition
the eye ball which is on the opposite side of the body of some other item of construction
Contralateral eye
Definition
describes how many neurons in an area of the visual cortex are ‘responsible’ for processing a stimulus of a given size, as a function of visual field location
Cortical magnification
Definition
describes the same data features across multiple scalable and interdependent layers. Each layer defines the information with the same level of accuracy, but adjusted for the level of scale
Distributed representation
Definition
a pathway that carries visual information from the primary visual cortex to the parietal lobe. According to one widely-accepted hypothesis, it carries information related to movement and spatial relationships between objects in the visual field. It is sometimes called the “where” pathway
Dorsal pathway
Definition
two related mental processes are shown to function independently of each other
Double dissociations
Definition
suggests the mechanisms involved in face processing are also engaged by objects with high within-class similarity for which people have become experts at rapid individuation
Expertise hypothesis
Definition
a subpart of the extrastriate visual cortex involved in the visual perception of human body and body parts, akin in its respective domain to the fusiform face area, involved in the perception of human faces
Extrastriate body area (EBA)
Definition
a device that measures brain activity by detecting changes associated with blood flow
Functional magnetic resonance imaging (fMRI)
Definition
a part of the human visual system that is specialized for facial recognition. It is located in the Inferior temporal cortex (IT)
Fusiform face area (FFA)
Definition
the elongated ridges on the floor of each lateral ventricle of the brain, thought to be the centre of emotion, memory, and the autonomic nervous system.
Hippocampus
Definition
Also known as the parietal stream or the “where” stream, this pathway stretches from the primary visual cortex (V1) in the occipital lobe forward into the parietal lobe. It is interconnected with the parallel ventral stream (the “what” stream) which runs downward from V1 into the temporal lobe
How pathway
Definition
a 1 mm block of V1 containing both the ocular dominance and orientation columns for a particular region in visual space
Hypercolumn
Definition
the eye located on the same side of the body as another structure or object
Ipsilateral eye
Definition
the behavioral task used in Ungerleider and Mishkin’s experiement in which they provided evidence for the dorsal, or where, visual processing stream
Landmark discrimination problem
Definition
a large cortical region that appears to play a central role in object recognition
Lateral occipital complex (LOC)
Definition
columns of the visual cortex that contain information from receptive fields at the same location on the retina
Location columns
Definition
cells project to the magnocellular layers of the lateral geniculate nucleus
M-ganglion cell
Definition
a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body
Magnetic resonance imaging (MRI)
Definition
a debate concerning the relationship between thought and consciousness in the human mind, and the brain as part of the physical body
Mind-body problem
Definition
the idea that there are self-contained areas in the brain that store mental processes such as the “lower level” reflexes
Modularity
Definition
functionally specialized cognitive systems that are domain-specific and may also contain innate knowledge about the class of information processed
Modules
Definition
a branch of psychology that aims to study the relationships between the brain and behaviour
Neuropsychology
Definition
the behavioral task used in ungerleider and mishkins experiment in which they provided evidence for the ventral, or what, visual processing stream
Object discrimination problem
Definition
Columns in the visual cortex that respond preferentially to one eye
Ocular dominance columns
Definition
organized regions of neurons that are excited by visual line stimuli of varying angles. These columns are located in the primary visual cortex (V1) and span multiple cortical layers
Orientation columns
Definition
cells project to the parvocellular layers of the lateral geniculate nucleus
P-ganglion cell
Definition
a region in the human collateral sulcus that responds more strongly to visual scenes (e.g. images of landscapes or cityscapes) than to other visual stimuli
Parahippocampal place area (PPA)
Definition
a neurological condition characterized by the inability to recognize the faces of familiar people
Prosopagnosia
Definition
the point-by-point representation of the retinal surface in another structure in the visual system, such as the striate cortex
Retinotopic map
Definition
an aspect of spatial perception and concerns the perception of spatial relationships
Spatial organisation
Definition
a pathway that carries visual information from the primary visual cortex to the temporal lobe. According to one widely-accepted hypothesis, it carries information related to object form and recognition
Ventral pathway
Definition
also known as the ventral stream, it leads to the temporal lobe, which is involved with object and visual identification and recognition
What pathway
Definition
Also known as the parietal stream or the “how” stream, this pathway stretches from the primary visual cortex (V1) in the occipital lobe forward into the parietal lobe. It is interconnected with the parallel ventral stream (the “what” stream) which runs downward from V1 into the temporal lobe
Where pathway
What is the order of the brain structures that signals from the retina pass through?
Signals from the retina travel through the optic nerve to the:
- Lateral geniculate nucleus (LGN)
- Primary visual receiving area in the occipital lobe (the striate cortex)
- And then through two pathways to the temporal lobe and the parietal lobe (what and how pathways)
- Finally ariving at the frontal lobe
What type of receptive field do all LGN cells have?
Center-surround
What is the major function of the LGN?
Regulate neural information from the retina to the visual cortex
Where does the LGN receive signals from?
Retina
Cortex
Brain stem
Thalamus
The LGN organises retinal signals by what categories?
Eye
Receptor type
Type of environmental information
Where do 90% of the fibers from the eye immediately project to?
Describe the bottom-up and top-down processing of the LGN
Top-down: information received from cortex
Bottom-up: information received from eyes
How many layers does the LGN have?
6
True or False:
Each layer of the LGN receives signals from only one eye
True
Which eye does layers 2,3 and 5 recieve signals from?
Ipsilateral eye
Which eye does layers 1, 4 and 6 recieve signals from?
Contralateral eye
Which LGN layers receive information from the ipsilateral eye?
2, 3 and 5
Which LGN layers receive information from the contralateral eye?
1, 4 and 6
True or False:
the LGN combines information from the left and right eyes
False
the LGN keeps information from the left and right eyes seperate in layers
How is the visual information in the LGN arranged?
Retinotopic map
How do you determine the retinotopic map of an organism?
Record from neurons with an electrode that penetrates the LGN obliquely
Stimulating receptive felds on the retina shows the location of the corresponding neuron in the LGN
Penetrating the LGN obliquely would pass through neurons with what in common?
Retinal receptive fields adjacent to one another
Penetrating the LGN perpendicular would pass through neurons with what in common?
Neurons with roughly the same visual field
True or False:
The cortex displays a retinotopic map
True
What types of neurons are found in the striate cortex?
Simple cortical cells
Complex cells
End-stopped cells
What does the receptive field of a simple cortical cells with an excitatory centre that favours vertical light look like?
What do simple cortical cells respond best to?
Respond best to bar of light oriented along the length of the receptive field
What does an orientation tuning curve show?
Shows response of simple cortical cell for orientations of stimuli
How are complex cells similar to simple cells? How are the different?
Similar: Respond to bars of light of a particular orientation
Different: Respond to moveent of bars of light in specific direction
What do end-stopped cells respond to? What do they not respond to?
Respond to: Moving lines of specific length; Moving corners or angles
No response to: Stimuli that are too long
What cortical cells are considered feature detectors?
Simple cortical cell
Complex cortical cell
End-stopped cortical cell
What is the term given to neurons that fire to specific features of a stimulus?
Feature detectors
What does neural fatigue or adaption to stimulus cause?
- Neural firing rate to decrease
- Neuron to fire less when stimulus immediately presented again
What is the method for selective adaptation?
- Measure sensitivity to tange of one stimulus characteristic (i.e. orientation)
- Adapt to that characteristic by extended exposure (i.e. staring)
- Re-measure the sensitivity/contrast threshold to range of the stimulus characteristic (see how adaptation has changed perception of the stimuli)
How does contrast threshold and orientation tuning curves demonstrate the link between perception and physiology?
What type of columns are found within the visual cortex?
Hypercolumns that contain:
Location columns
Orientation columns
Ocular dominance columns
Removal of the ____________ lobe tissue resulted in problems with the object discrimination task
Removal of the temporal lobe tissue resulted in problems with the object discrimination task
Removal of the ____________ lobe tissue resulted in problems with the landmark discrimination task
Removal of the parietal lobe tissue resulted in problems with the landmark discrimination task
What do both the what and where/how pathways have in common?
- Originate in retina and continue through ganglion cells in the LGN
- Have some interconnections
- Receive feedback from higher brain areas
What type of ganglion cell is involved in the parietal “where” pathway?
M-ganglion cells
What type of ganglion cell is involved in the temporal “what” pathway?
P-ganglion cell
Which has a larger receptive field: M- or P-ganglion cells?
M-ganglion cell
Large receptive field makes it easier to determine location
Which visual pathway helps determine function of an observed object?
Where/how pathway
Which region of the brain responds best to faces in monkeys? What about humans?
Monkeys: Inferotemporal (IT) cortex
Humans: Fusiform face area (FFA)
What does damage to the fusiform face area (FFA) cause?
Face blindness
Fusiform face area (FFA) responds best to ___________
Parahippocampal place area (PPA) responds best to _________________
Extrastriate body area (EBA) responds best to __________________
Lateral occipital complex (LOC) responds best to _________
Fusiform face area (FFA) responds best to faces
Parahippocampal place area (PPA) responds best to spatial layout
Extrastriate body area (EBA) responds best to pictures of full bodies and body parts
Lateral occipital complex (LOC) responds best to objects
What is the evidence that nature is the main cause of neural specialisation? What about for nurture?
Nature:
- Newborn monkeys respond to direction of movement and depth of objects
- Babies prefer looking a picture of assembled parts of faces
Nurture:
- Brain imaging experiments show areas that respond best to letters and words
- fMRI experiments whoe that training results in areas of the FFA responding best to:
- Cars and birds for experts in these areas
- Greeble stimuli
