Transcript spatial cognition - UCSD Cognitive Science

SPATIAL COGNITION
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Spatial Cognition is concerned
with the acquisition, organization,
utilization, and revision of
knowledge about spatial
environments. These capabilities
enable humans to manage basic
and high-level cognitive tasks in
everyday life.
SPATIAL COGNITION
A Couple Aspects of Spatial Cognition:
I. Visuospatial Perception
including "Spatial Awareness"
a. Spatial Coordinate Systems or
Spatial Reference Frames.
b. Spatial Feature Integration
II. Spatial Navigation
a. spatial cognitive map and
route finding.
b. path integration
Neuroanatomy of Spatial Cogntion???
A. Ventral Visual Stream leading downward
into the temporal lobe
(inferotemporal cortex - IT).
What is it?
B. Dorsal Visual Stream leading upward or
forward into the Parietal Cortex (area
PG).Where is it?
Dorsal and Ventral Streams:Parallel systems
with substantial interconnectivity.
What’s the Parietal Lobe
Doing?
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Attention
Neglect
Simultanagnosia (in Balint’s syndrome)
Optic Ataxia
Spatial representation
Apraxia
Visuomotor integration
Hemisphere diffs
Hypothesis:
Parietal Cortex neurons construct space by combining
multi-sensory modalities with motor signals.
• VIP: Perioral space
– visual + tactile responses
– Tactile RFs are centered around the mouth
– V+T units have similar movement direction
tuning
– Visual responses can be eye- or head-centered
– Some visual responses are tuned to movement
of an object toward a particular portion of the
face, independent of gaze
– Some visual responses are sensitive only to
stimuli that are near the face (< 5cm)
– Connected to F4, which controls head/mouth
movements
• AIP: Object Shape
– Visual, motor, and visuo+motor responses
– Visual units are object shape and orientation
sensitive
– Motor responses are hand-movement sensitive
– Deactivation causes grasping deficits
– Connected to area F5, which is involved in
grasping
*Grasping with hand
• MIP: Immediate Extrapersonal Space
– Visual, somato, and bimodal units
– Pure somato units have RFs on the hand
– Bimodal units activate strongly during reaching
– Some pure visual units show stronger
responses when a target is within reaching
distance
– Bimodal RFs are located near each other
(tactile RF on the hand = visual RF near hand)
• Visual RF moves with hand!
• Visual RF expands when monkey uses a tool for
reaching!
*Reaching with arm
"Spatial Awareness" - Posterior Parietal Cortex
LIP (lateral intraparietal)Neurons respond to the onset of visual stimuli.
Visual responses are enhanced by
requiring that the monkey attends to the stimulus.
Prolonged responses occur
when the monkey must remember the location of in
which the stimulus occurred.
Neurons contribute to the updating of the
internal image.
"Eye-centered spatial representation"
Parietal Cortex Neurons in Rats
Reflect Route traversals
Behavioral Correlates of PC
Neurons
For parietal neurons, high correlations were observed between outbound and
inbound unit activity vectors aligned according to behavioral sequence (first
versus second traces = rbeh), but were negative when aligned according to
the sequence of spatial positions encountered (first versus third traces =
rspace). The opposite pattern was observed for the CA1 hippocampal
neuron.
Recording Cells in the
Hipocampus
(Does it have a spatial map?)
Hippocampal Cell Layers
Hippocampal Cell Layers
Electrodes Finding Cells
Computer Monitoring of Activity
After Amplification
Hippocampal Pyramidal Cell
Complex Spike
Place cells are stable when the entire
environment rotates as long as the animal is
not disoriented during the rotation.
Place Field on Circular Track
Place Field Expansion
Place Field Expansion
Spatial “Grid Cells” in Entorhinal Cortex
Grid Cells:
Tessellation of a city map by squares provides information about position,
distance and direction, allowing specific places to be easily located. b, Hafting
et al.1 find that as a rat explores an experimental enclosure, the discharge rate
of a neuron in the dorsocaudal medial entorhinal cortex increases at regular
intervals corresponding to the vertices of a triangular grid. c, Integration of
information from several grid components (that is, from the outputs of
several neurons) can increase the spatial resolution of the environment.
Three triangular grids are represented here, with red displaced and blue
rotated relative to a neuron grid shown in black. GR
GRID CELLS DON’T SCALE
GRID Cells Align to External Cues,
but persist when the cues are
removed.
Grids
persist in
the dark!
GRID Cells Code
similarly in different
environments
Navigational-related structural change
in the Hippocampi of Taxi Drivers
Maguire, Gadian, Johnsrude, Good, Ashburner, Frackowiak & Frith.
Presented by Jill Campbell, Monica Chattha, James Collins
Kellie Gray and Kristen Lai Fatt
Background
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The hippocampus is KNOWN to be involved in
spatial navigation & cognition in animals
– ↑ in relative hippocampal volume in small mammals
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and birds that engage in behaviour requiring spatial
memory (i.e. food storing)
↑ in hippocampal volumes specifically during seasons
when demand for spatial ability greatest – species
specific
 tendency for animal hippocampi to undergo
structural changes in response to behaviour
requiring spatial memory
Hippocampal refresher
Background
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The hippocampus is strongly BELIEVED to play
a similar role in humans
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structural brain differences b/w distinct groups of
subjects documented (ex. Males vs. females,
musicians vs. non-musicians)
lesion work and functional neuroimaging have
confirmed the involvement of human hippocampus in
spatial memory and navigation but not its precise role
 differences in brain morphology predetermined
OR due to plastic change in response to
environmental stimulation??
Hypothesis
 In healthy humans, the hippocampus will be
the most likely brain region to show physical
changes associated with extensive navigation
Analysis of volumes for 3 sections of the
hippocampus
Volume
Anterior
Body
Posterior
Control:larger
No difference
b/n grps
Taxi grp:
larger
Right side
was larger
(for control)
none
insignificant
Hemisphere Right side was
larger (for
control)
none
Interaction
none
Changes with Navigation Experience
• The more time spent being a taxi driver, the larger the
right posterior hippocampus
•The more time spent being a taxi driver, the smaller
the anterior hippocampus
Implications
• Plasticity of hippocampus results from spatial experience
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Extensive spatial experience causes growth of posterior
hippocampus
•
Trade off between size of Anterior and Posterior
hippocampus
•
Posterior HC = storage of previously learned
spatial information in humans
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Anterior HC = encoding of new spatial environment
in humans
 If this is true then Taxi Drivers should be slower
at learning spatial orientation of completely new &
unique environments