SPATIAL COGNITION

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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.

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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
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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 StreamsParallel
systems with substantial interconnectivity.
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Whats the Parietal Lobe Doing?

• Attention
• Neglect
• Simultanagnosia (in Balints syndrome)
• Optic Ataxia
• Spatial representation
• Apraxia
• Visuomotor integration
• Hemisphere diffs

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Hypothesis Parietal Cortex neurons construct
space by combining multi-sensory modalities with
motor signals.
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• VIP Perioral space
• visual tactile responses
• Tactile RFs are centered around the mouth
• VT 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 (lt 5cm)
• Connected to F4, which controls head/mouth
  movements
• Head movt / grasping with mouth

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• AIP Object Shape
• Visual, motor, and visuomotor 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

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• 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

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"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"
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Parietal Cortex Neurons in RatsReflect Route
traversals
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Behavioral Correlates of PC Neurons
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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.
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Recording Cells in the Hipocampus(Does it have a
spatial map?)
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Hippocampal Cell Layers
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Hippocampal Cell Layers
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Electrodes Finding Cells
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Computer Monitoring of Activity After
Amplification
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Hippocampal Pyramidal Cell Complex Spike
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Place cells are stable when the entire
environment rotates as long as the animal is not
disoriented during the rotation.
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Place Field on Circular Track
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Place Field Expansion
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Place Field Expansion
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Spatial Grid Cells in Entorhinal Cortex
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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
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GRID CELLS DONT SCALE
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GRID Cells Align to External Cues, but persist
when the cues are removed.
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Grids persist in the dark!
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GRID Cells Code similarly in different
environments
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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
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Background

• The hippocampus is KNOWN to be involved in
  spatial navigation cognition in animals
• ? in relative hippocampal volume in small mammals
  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

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Hippocampal refresher
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Background

• The hippocampus is strongly BELIEVED to play a
  similar role in humans
• 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??

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Hypothesis
? In healthy humans, the hippocampus will be the
most likely brain region to show physical changes
associated with extensive navigation
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Analysis of volumes for 3 sections of the
hippocampus
Anterior Body Posterior
Volume Controllarger No difference b/n grps Taxi grp larger
Hemisphere Right side was larger (for control) Right side was larger (for control) insignificant
Interaction none none none
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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

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Implications

• Plasticity of hippocampus results from spatial
  experience
• 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
• 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