Chapter 21 Flashcards
spatial behavior
behaviors to guide our bodies through space
topographic memory
the ability to orient oneself to move through space
- derives from idea that movements take place between or in relation to points or objects that are spatially distinct such as the points of a map
body space
clothes or contact with external objects can be localized
- perceptual impairments - affect body schema causing body disorientation and body neglect
grasping space
surrounding the body, monitored by ventral visual field
distal space
body moves through, monitored by dorsal visual field
time space
alternating awareness - bind together the awareness of oneself as continuous entity through time
Topographic Disorientation
inability to orient oneself in relation to one’s environment, even in environments that are pretty familiar to them before the injury
topographic disorientation
deficits
- fails to recognize previously familiar individual landmarks
- can no longer compute the relationship between landmarks
- impaired in spatial guidance
types of topographic disorientation
retrograde spatial amnesia, anterograde spatial amnesia, egocentric disorientation, heading disorientation, landmark agnosia, anterograde disorientation, spatial distortion deficits
retrograde spatial amnesia
inability to navigate in environments that were familiar before
anterograde spatial amnesia
- inability to navigate in novel environments
- but can navigate in environments that were familiar before
egocentric disorientation
unable to represent the location of objects with respect to self
- have either unilateral or bilateral injuries in posterior parietal cortex
- can gesture towards objects as long as their eyes are open → ability is lost when eyes closed
- performance impaired during visual spatial tasks, including mental rotation (ability to visualize appearance of 3D objects from different perspectives) and ability to judge distances between objects
- impaired in wayfinding tasks both in formerly familiar and in novel environments
heading disorientation
unable to represent direction of orientation with respect to environment
- unable to set a course to where they want to go
- able to recognize landmarks, to recognize their own location in relation to those landmarks, and to describe where they are
- injury in the right posterior cingulate cortex
landmark agnosia
unable to use prominent environmental features to orient themselves
- can recognize churches, houses, and other landmarks so they do not have a deficit in perceiving environmental information
- cannot use a particular church or house to guide their movement
- lesion sites either bilateral or solely confined to the right side of the medial aspect of occipital lobe including the lingual and fusiform gyri as well as the parahippocampal gyrus
anterograde disorientation
unable to learn new representations of environmental information
- no problem navigating in formerly familiar environments but experience difficulty in novel environments
- inability to learn about unfamiliar objects by looking at them
- If shown a novel object they are not likely to be able to select it from an array of objects a short while later in contrast they are able to recall auditory and tactile information that is novel
- damage in the parahippocampal gyrus of the inferior ventral cortex on the right side
spatial distortion deficits
unable to perceive themselves accurately relative to the environment
- seeing themselves as too small or too large relative to their spatial world
- out-of-body experiences consisting of seeing themselves as occupying space at a distance from their body or imagining that they have more than one body
- damage to medial parietal lobe extending to the cingulate cortex
dual-stream theory
- starts in visual cortex
- what pathway: through the temporal lobes, identifies objects
- where pathway: projects through the parietal lobe, guides movement
- frontal lobe: synthesize what and where
dual stream theory
what pathway
through the temporal lobes, identifies objects
dual stream theory
where pathway
projects through the parietal lobe, guides movement
dual stream theory
frontal lobe
synthesize what and where
three dorsal stream targets theory
- Visual information enters a domain in parietal cortex that then sends projection to premotor cortex, prefrontal cortex, and the medial temporal lobe
- visually guided action (the premotor cortex)
- spatial navigation (the prefrontal cortex)
- spatial memory (the medial temporal lobe)
three dorsal stream targets theory
parieto-premotor pathway
visually guided action
premotor cortex
three dorsal stream targets theory
parieto-medial temporal pathway
spatial memory
medial temporal lobe
three dorsal stream targets theory
parieto-prefrontal pathway
spatial navigation
prefrontal cortex
deficits in visuospatial exploration
result from?
list
(result from bilateral parietal lesions)
- displaced visual attention
- inability to perceive more than one stimulus
- defective visual control of movement (optic ataxia)
- inability to follow a moving target (motion blindness)
- defective accommodation and convergence
- inability to maintain fixation
- inability to direct gaze to targets voluntarily (gaze apraxia)
- abnormal visual search
balint’s syndrome
damage
bilateral damage to the occipital and parietal cortex including parts of the dorsal temporal lobe, zone of unilateral damage to the dorsal parietal and motor cortex
in patients w hemineglect:
- defective eye movements may mimic ocular apraxia
- difficulty in performing hand movements may mimic optic ataxia
- deficits in perception can mimic simultagnosia
balints syndrome
describe
deficits in visuospatial exploration
- inability to visualize more than one object in the visual field at a time
- inability to identify different items inn a visual scene simultaneously
- failure to reach an object w rt hand but able to do so with left
- optic ataxia
- oculomotor apraxia
- wiggling activates attention
- simultagnosia
- ex: when provided w a pic of forest w trees, they are unable to see the forest, although they can see individual tree
optic ataxia
lack of coordination between visual input and hand movements
ocuolomotor apraxia
inability to voluntarily shift gaze despite the intact function of extraocular muscles
simultagnosia
lack of ability to perceive more than a single object at a time
balints sydrome
preserved and deficits
- preserved:
- complete visual fields
- capable of eye movements
- ability to name colors, objects, and pictures
- deficits:
- after his attention had been directed to an object he noticed nothing else
visual localization
task: projected one or two dots on a screen for 3000 milliseconds, 2 sec later then projected an array of numbers and subjects asked to pick the number or numbers located in that same position or positions as the dot
patients with rt hemi lesions - impaired
depth perception
task: random dot stereograms
- intact patients and patients w left hemi damage - easily percieved contour
- patients with rt hemi damage - deficit in depth perceptionn
- → some part of the mechanism for depth perception is more strongly represented in the right hemisphere.
parietal cortex
spatial
- closely linked to body senses
- likely contribution is to provide spatial coordinate system related to the body → to aid us in locating objects inn space relative to ourselves, especially in egocentric coordinates
- contains neurons that have role in directing body, hand, and eye movements toward stimuli, providing further evidence that the parietal cortex has a special role inn directing movements to targets relative to body coordinates
Frontal Cortex Involvement
important in spatial demonstration
nakamura: spared all of the visual areas of the posterior cortex while removing the entire cortex anterior to it in monkeys
- failed to show any signs of vision
- normal functioning of cells in the visual areas
- conclusion: removal of the frontal cortex renders animals chronically blind and unable to navigate even though the visual system, at least the early visual system, is still functioning properly
goldman-rakic: rhesus monkeys in dorsolateral prefrontal lobe along principal sulcus
- orienting deficits in rhesus monkeys in dorsolateral prefrontal lobe along principal sulcus
- similar pattern found in people with frontal lobe damage
temporal cortex involvement in spatial
combine egocentric spatial guidance with allocentric spatial guidance related to objects in a complex pattern of routes through numerous temporal lobe regions including the cingulate cortex, the parahippocampal gyrus, the internal cortex in various cell fields of the hippocampus
dorsal and ventral stream
dorsal stream
temporal cortex
spatial navigation
ventral stream
temporal cortex
object perception
where ventral and dorsal streams converge
hippocampus
lesion to hippocampus
- lesion to hippocampus: can still produce what was called a schematic cognitive map of the environment in which they lived before the injury, their memory of that environment’s rich contextual details is impaired and they’re usually not able to navigate that present environment
- right parahippocampal gyrus is sufficient for learning a single location but additional temporal lobe structures including the hippocampus are necessary for more complex spatial memory including the memory of having previously performed and learned the task
taxi drivers
- four-year course devoted to learning London streets layout trainees
- increased gray matter volume in the most posterior part of the hippocampus as shown in orange and yellow areas in the figure
route following/cue learning
- a response made to a specific cue
- ex: following a road or path, moving toward a landmark, or reaching for an object that we can see
landmark agnosia
unable to identify familiar places
piloting (aka x2)
- ability to find a place without a direct cue
- aka topographic guidance
- guided by rich array of environmental cues or cognitive mapping on the assumption that guidance is provided by neural processes that represent the environment in map-like coordinates
- aka place learning
- goal of our trip is to reach a specific place or local navigation which again emphasizes the importance of location
caching behavior
- natural food caching activity of speciesex: food caching birds can remember hundreds of locations at which food is stored
- use distal spatial cues to locate food
- require a hippocampus to do so suggesting that the hippocampus plays an important role in spatial behavior
- hippocampus
dead reckoning
- ability to monitor one’s movement speed, travel time, and directional changes
- path integration
- integrating an outward path provides information about present location and also information about how to set a direct course homeward
- hippocampal formation contributes
patients who had undergone elective surgery to remove the hippocampus as a treatment for epilepsy
task: test of object recall and asked to place the objects in same arrangement
- name recall - both patients with right and with left hippocampus damage were moderately impaired
- patients with left hippocampal damage had lower scores compared to the right hippocampal patients
visualization tests
evaluate ability to manipulate, rotate, twist, or invert two or three dimensional stimuli
amnesic patients including patients with hippocampal damage
task: subjects are presented with a picture within a frame and are asked to draw it
- amnesic patients including patients with hippocampal damage → display spatial performance superior to that of control participants
- health control - draw the object with a reduced size relative to the frame.
- boundary expansion - displayed by control participants but not amnesic patients
- amnesiac patients - produce an accurate drawing of he object relative to the size of the frame
place cells
- discharge when an animal enters a specific location in its environment
- Within a short time of a rat being placed in a novel environment hippocampal formation place cells begin to discharge in relation to the animal’s location
- place-by-direction cells encode the location, direction, and speed
- if lights are turned off after animals have explored new environment, place cells maintain their activity relative to the previously visualized cue locations
- if the rat is walking on a straight path active place cells are more likely to code by direction as well as location
- only hippocampal place cells appear to change activity in response to changes in environmental cues
head direction cells
- discharge when a rats head is pointed in a particular direction
- maintain their rate of discharge as long as the head is in the preferred direction
- discharge even when the animal is restrained
- not activated by the presence of a particular object in environment rather such a cell is responsive to direction itself
grid cells
- discharge at regular spatial intervals that divide the environment into a grid
- invariant in the face of changes in the animal’s direction, movement, or speed
- different cells at the same location have the same grid spacing and orientation relative to the environment, but they differ in node location
- cells located in different parts of the medial entorhinal cortex demark grids of different sizes, as if to map the size of the environment
place system
allows animal to navigate by using the relations between environmental cues (allocentric guidance)
head direction system
allows animal to navigate in relation to its own spatial position
grid system
provides a spatial framework that indicates the size of a space and the animal’s location in that space
hippocampus
patient RB
- role in memory especially in episodic memory
- patient RB
- a bilateral loss of cells in a part of the hippocampus led to the anterograde amnesia and spatial impairments
spatial memory as distinct from episodic memory
argument for the idea that spatial memory is distinct from other episodic memory comes from studying people who have no known brain injury and who display selective spatial disabilities
developmental topographic disorientation (DTD)
inability to integrate landmarks and derive navigational information from them, navigate through aa nonverbal process, or generate cognitive maps
frequently lost or disoriented even in their own homes or in the surrounding neighborhood
spatial and episodic memory as hippocampal functions
theories
dual contribution theory
scene construction theory
dual contribution theory
- spatial and episodic memory are two hippocampal functions
- Dorsal stream projections to the medial temporal lobe contribute to spatial memory
- ventral stream processes contribute to episodic memory
- damage to the hippocampus impairs both
scene construction theory
- most of our spatial imagination future thinking and even memory distortion is related to scene construction
- produce a higher order memory composite which is in the form of spatially coherent scenes
- hippocampus functions for neither spatial memory nor episodic memory, rather the hippocampus employs both to create more namely spatially coherent scenes that involve four elements:
- spacial navigation
- episodic memory
- imagining
- future thinking
- based on numerous lines of evidence including their findings that all four elements of spatially coherent scenes are lost together in people with hippocampal damage
theory of mind
- the ability to attribute mental states to ourselves and others and to understand that others experience similar states
- tested by giving them a picture for example of a family having a picnic and questioning them about the family members’ activities past, present, and future
- Amnesic subjects including patients with complete absence of hippocampus do demonstrate that they have a theory of mind but it is stereotypical in its features and probably based on the semantic knowledge of what people may typically do, have done, or might do
- Control participants provide richer descriptions and make more complex decisions
_____ memory is the name given to the ability to move through space from one place to another.
topographic
You see a patient in clinic who exhibits an inability to represent the location of objects with respect to herself. This deficit would be termed:
egocentric disorientation
Patients with heading disorientation are unable to plan a course of direction, despite being able to describe where they want to go. This disorder is associated with lesions to which brain region?
right posterior cingulate cortex
The form of topographic disorientation in which individuals cannot use prominent environmental features for orientation is called _____.
landmark agnosia
Goldman-Rakic and coworkers found that there is a spatial impairment in the visual detection deficits observed in monkeys with _____ lobe lesions.
frontal
The studies conducted on food caching in birds may demonstrate that:
- testosterone is crucial to producing birdsong and also to remembering cache sites
- birds who cache seeds have a larger hippocampus
- African and Asian birds are more likely to use dead reckoning to find their cache sites
- irds with frontal lobe lesions show no difficulty in finding the seeds that they have cached
birds who cache seeds have a larger hippocampus
Which is NOT a type of cell discovered in the hippocampus and thought to play a role in spatial behavior?
- complex
- place
- head direction
- grid
complex
Which is NOT a brain region where place cells have been found to exist?
- the hippocampus
- the entorhinal cortex
- the dentate gyrus
- the subiculum
the dentate gyrus
behaviors to guide our bodies through space
spatial behavior
the ability to orient oneself to move through space
- derives from idea that movements take place between or in relation to points or objects that are spatially distinct such as the points of a map
topographic memory
clothes or contact with external objects can be localized
- perceptual impairments - affect body schema causing body disorientation and body neglect
body space
surrounding the body, monitored by ventral visual field
grasping space
body moves through, monitored by dorsal visual field
distal space
alternating awareness - bind together the awareness of oneself as continuous entity through time
time space
inability to orient oneself in relation to one’s environment, even in environments that are pretty familiar to them before the injury
Topographic Disorientation
- fails to recognize previously familiar individual landmarks
- can no longer compute the relationship between landmarks
- impaired in spatial guidance
topographic disorientation can occur bc:
retrograde spatial amnesia, anterograde spatial amnesia, egocentric disorientation, heading disorientation, landmark agnosia, anterograde disorientation, spatial distortion deficits
types of topographic disorientation
inability to navigate in environments that were familiar before
retrograde spatial amnesia
- inability to navigate in novel environments
- but can navigate in environments that were familiar before
anterograde spatial amnesia
unable to represent the location of objects with respect to self
- have either unilateral or bilateral injuries in posterior parietal cortex
- can gesture towards objects as long as their eyes are open → ability is lost when eyes closed
- performance impaired during visual spatial tasks, including mental rotation (ability to visualize appearance of 3D objects from different perspectives) and ability to judge distances between objects
- impaired in wayfinding tasks both in formerly familiar and in novel environments
egocentric disorientation
unable to represent direction of orientation with respect to environment
- unable to set a course to where they want to go
- able to recognize landmarks, to recognize their own location in relation to those landmarks, and to describe where they are
- injury in the right posterior cingulate cortex
heading disorientation
unable to use prominent environmental features to orient themselves
- can recognize churches, houses, and other landmarks so they do not have a deficit in perceiving environmental information
- cannot use a particular church or house to guide their movement
- lesion sites either bilateral or solely confined to the right side of the medial aspect of occipital lobe including the lingual and fusiform gyri as well as the parahippocampal gyrus
landmark agnosia
unable to learn new representations of environmental information
- no problem navigating in formerly familiar environments but experience difficulty in novel environments
- inability to learn about unfamiliar objects by looking at them
- If shown a novel object they are not likely to be able to select it from an array of objects a short while later in contrast they are able to recall auditory and tactile information that is novel
- damage in the parahippocampal gyrus of the inferior ventral cortex on the right side
anterograde disorientation
unable to perceive themselves accurately relative to the environment
- seeing themselves as too small or too large relative to their spatial world
- out-of-body experiences consisting of seeing themselves as occupying space at a distance from their body or imagining that they have more than one body
- damage to medial parietal lobe extending to the cingulate cortex
spatial distortion deficits
- starts in visual cortex
- what pathway: through the temporal lobes, identifies objects
- where pathway: projects through the parietal lobe, guides movement
- frontal lobe: synthesize what and where
dual-stream theory
through the temporal lobes, identifies objects
dual stream theory
what pathway
projects through the parietal lobe, guides movement
dual stream theory
where pathway
synthesize what and where
dual stream theory
frontal lobe
- Visual information enters a domain in parietal cortex that then sends projection to premotor cortex, prefrontal cortex, and the medial temporal lobe
- visually guided action (the premotor cortex)
- spatial navigation (the prefrontal cortex)
- spatial memory (the medial temporal lobe)
three dorsal stream targets theory
visually guided action
premotor cortex
three dorsal stream targets theory
parieto-premotor pathway
spatial memory
medial temporal lobe
three dorsal stream targets theory
parieto-medial temporal pathway
spatial navigation
prefrontal cortex
three dorsal stream targets theory
parieto-prefrontal pathway
(result from bilateral parietal lesions)
- displaced visual attention
- inability to perceive more than one stimulus
- defective visual control of movement (optic ataxia)
- inability to follow a moving target (motion blindness)
- defective accommodation and convergence
- inability to maintain fixation
- inability to direct gaze to targets voluntarily (gaze apraxia)
- abnormal visual search
deficits in visuospatial exploration
result from?
list
bilateral damage to the occipital and parietal cortex including parts of the dorsal temporal lobe, zone of unilateral damage to the dorsal parietal and motor cortex
balint’s syndrome
damage
deficits in visuospatial exploration
- inability to visualize more than one object in the visual field at a time
- inability to identify different items inn a visual scene simultaneously
- failure to reach an object w rt hand but able to do so with left
- optic ataxia
- oculomotor apraxia
- wiggling activates attention
- simultagnosia
- ex: when provided w a pic of forest w trees, they are unable to see the forest, although they can see individual tree
balints syndrome
describe
lack of coordination between visual input and hand movements
optic ataxia
inability to voluntarily shift gaze despite the intact function of extraocular muscles
ocuolomotor apraxia
lack of ability to perceive more than a single object at a time
simultagnosia
- preserved:
- complete visual fields
- capable of eye movements
- ability to name colors, objects, and pictures
- deficits:
- after his attention had been directed to an object he noticed nothing else
balints sydrome
preserved and deficits
- intact patients and patients w left hemi damage - easily percieved contour
- patients with rt hemi damage - deficit in depth perceptionn
- → some part of the mechanism for depth perception is more strongly represented in the right hemisphere.
depth perception
task: random dot stereograms
- closely linked to body senses
- likely contribution is to provide spatial coordinate system related to the body → to aid us in locating objects inn space relative to ourselves, especially in egocentric coordinates
- contains neurons that have role in directing body, hand, and eye movements toward stimuli, providing further evidence that the parietal cortex has a special role inn directing movements to targets relative to body coordinates
parietal cortex
spatial
important in spatial demonstration
Frontal Cortex Involvement
combine egocentric spatial guidance with allocentric spatial guidance related to objects in a complex pattern of routes through numerous temporal lobe regions including the cingulate cortex, the parahippocampal gyrus, the internal cortex in various cell fields of the hippocampus
dorsal and ventral stream
temporal cortex involvement in spatial
temporal cortex
spatial navigation
dorsal stream
temporal cortex
object perception
ventral stream
- lesion to ____: can still produce what was called a schematic cognitive map of the environment in which they lived before the injury, their memory of that environment’s rich contextual details is impaired and they’re usually not able to navigate that present environment
lesion to hippocampus
- four-year course devoted to learning London streets layout trainees
- increased gray matter volume in the most posterior part of the hippocampus as shown in orange and yellow areas in the figure
taxi drivers
- a response made to a specific cue
- ex: following a road or path, moving toward a landmark, or reaching for an object that we can see
route following/cue learning
unable to identify familiar places
landmark agnosia
- ability to find a place without a direct cue
- aka topographic guidance
- guided by rich array of environmental cues or cognitive mapping on the assumption that guidance is provided by neural processes that represent the environment in map-like coordinates
- aka place learning
- goal of our trip is to reach a specific place or local navigation which again emphasizes the importance of location
piloting (aka x2)
- natural food caching activity of speciesex: food caching birds can remember hundreds of locations at which food is stored
- use distal spatial cues to locate food
- require a hippocampus to do so suggesting that the hippocampus plays an important role in spatial behavior
- hippocampus
caching behavior
- ability to monitor one’s movement speed, travel time, and directional changes
- path integration
- integrating an outward path provides information about present location and also information about how to set a direct course homeward
- hippocampal formation contributes
dead reckoning
- name recall - both patients with right and with left hippocampus damage were moderately impaired
- patients with left hippocampal damage had lower scores compared to the right hippocampal patients
patients who had undergone elective surgery to remove the hippocampus as a treatment for epilepsy
task: test of object recall and asked to place the objects in same arrangement
evaluate ability to manipulate, rotate, twist, or invert two or three dimensional stimuli
visualization tests
- amnesic patients including patients with hippocampal damage → display spatial performance superior to that of control participants
- health control - draw the object with a reduced size relative to the frame.
- boundary expansion - displayed by control participants but not amnesic patients
- amnesiac patients - produce an accurate drawing of he object relative to the size of the frame
amnesic patients including patients with hippocampal damage
task: subjects are presented with a picture within a frame and are asked to draw it
- discharge when an animal enters a specific location in its environment
- Within a short time of a rat being placed in a novel environment hippocampal formation place cells begin to discharge in relation to the animal’s location
- place-by-direction cells encode the location, direction, and speed
- if lights are turned off after animals have explored new environment, place cells maintain their activity relative to the previously visualized cue locations
- if the rat is walking on a straight path active place cells are more likely to code by direction as well as location
- only hippocampal place cells appear to change activity in response to changes in environmental cues
place cells
- discharge when a rats head is pointed in a particular direction
- maintain their rate of discharge as long as the head is in the preferred direction
- discharge even when the animal is restrained
- not activated by the presence of a particular object in environment rather such a cell is responsive to direction itself
head direction cells
- discharge at regular spatial intervals that divide the environment into a grid
- invariant in the face of changes in the animal’s direction, movement, or speed
- different cells at the same location have the same grid spacing and orientation relative to the environment, but they differ in node location
- cells located in different parts of the medial entorhinal cortex demark grids of different sizes, as if to map the size of the environment
grid cells
allows animal to navigate by using the relations between environmental cues (allocentric guidance)
place system
allows animal to navigate in relation to its own spatial position
head direction system
provides a spatial framework that indicates the size of a space and the animal’s location in that space
grid system
- role in memory especially in episodic memory
- a bilateral loss of cells in a part of the hippocampus led to the anterograde amnesia and spatial impairments
hippocampus
patient RB
inability to integrate landmarks and derive navigational information from them, navigate through aa nonverbal process, or generate cognitive maps
frequently lost or disoriented even in their own homes or in the surrounding neighborhood
developmental topographic disorientation (DTD)
dual contribution theory
scene construction theory
spatial and episodic memory as hippocampal functions
theories
- spatial and episodic memory are two hippocampal functions
- Dorsal stream projections to the medial temporal lobe contribute to spatial memory
- ventral stream processes contribute to episodic memory
- damage to the hippocampus impairs both
dual contribution theory
- produce a higher order memory composite which is in the form of spatially coherent scenes
- hippocampus functions for neither spatial memory nor episodic memory, rather the hippocampus employs both to create more namely spatially coherent scenes that involve four elements:
- spacial navigation
- episodic memory
- imagining
- future thinking
- based on numerous lines of evidence including their findings that all four elements of spatially coherent scenes are lost together in people with hippocampal damage
scene construction theory
- the ability to attribute mental states to ourselves and others and to understand that others experience similar states
- tested by giving them a picture for example of a family having a picnic and questioning them about the family members’ activities past, present, and future
- Amnesic subjects including patients with complete absence of hippocampus do demonstrate that they have a theory of mind but it is stereotypical in its features and probably based on the semantic knowledge of what people may typically do, have done, or might do
- Control participants provide richer descriptions and make more complex decisions
theory of mind
