Spatial Learning

Question 1

OLTON & SAMUELSON (1976)

Answer 1

• how do animals learn spatial locations/routes in radical maze?
• WM = remembering places w/trial (ie. remember which arms already visited)
• reference memory = remember places between trials (ie. remember which arms contain food)
• rats learn spatial relations between arms/external landmarks rather than following rule/marking visited arms
• Q: which tests/evidence required for conclusion?

Question 2

HIPPOCAMPAL LESIONS IMPAIR SPATIAL LEARNING

Answer 2

• control condition in hippocampus lesion studies = non-spatial learning (cued learning)
  HUMANS
• declarative (facts) memories lost w/hippocampal damage BUT not procedural memories; old memories oft NOT lost
  ANIMALS
• hippocampus = important for acquisition of new info/spatial learning

Question 3

REINER (2009)

Answer 3

• new way of thinking about avian forebrain organisation/beh capabilities
• aka. spatial learning in birds
• hippocampus = involved in spatial orientation/learning in birds

Question 4

NAVIGATION

Answer 4

WHERE AM I?
- reference to abstract map/allocentric representation; allows to plan for novel route w/o learning it
HOW DO I GET FROM HERE -> GOAL LOCATION?
- following learned routes, novel routes link to learned info; egocentric/allocentric representations

Question 5

WOLF (2011)

Answer 5

• path integration in desert ant
• multimodal sensory info used
• cognitive map = using visual allocentric cues in object-centred reference frame to infer direction/distance
• view-matching = inferring direction/distance from views matched w/memorised views in egocentric frame of reference (ie. retiontopic maps)
• path integration (dead reckoning) = updating location/directional orientation by recording idiothetic cues over long distances (ie. turns/steps/odometry); prone to cummulative error

Question 6

EKSTRON, ARNOLD & IARIA (2014)

Answer 6

• pointing tasks
• egocentric pointing task = SOP task (ie. please point to ice-cream shop)
• allocentric pointing = JRD task (ie. imagine you’re standing at bookstore facing fast food restaurant; point to camera store)
• accuracy increased in JRD task
• humans may rely on allocentric knowledge for some tasks
• most ethological situations can be solved w/both; could be continuum how each contributes

Question 7

JRD TASK

Answer 7

• judgements of relative direction task
• human spatial cognition assay
• requires language use
• pps recall spatial layout in mind for pointing to landmark relative to others
• BUT independent of pps physical position/heading

Question 8

SOP TASK

Answer 8

• scene/orientation-dependent pointing task
• verbal instructions
• pps see scene; asked to point to landmarks relative to pps position/heading

Question 9

RINALDI ET AL. (2020)

Answer 9

• flexible use of allocentric/egocentric spatial memories activates dif neural networks in mice
• allocentric navigation isn’t only dependent on hippocampus but also distributed neural circuits (dorsomedial striatum/nucleus accumbens/prelimbic & infralimbic cortex)
• retrieval of allocentric/egocentric info = mediated by distinct neural systems

Question 10

FILIMON (2015)

Answer 10

• egocentric/allocentric representations in humans
• widely suggested that humans/mammals have cognitive maps based on allocentric representations in brain
• BUT many brain areas map spatila location of objects in egocentric reference frame (ie. relative to eye/head/hand) in (ie.) parieto-frontal cortex
• Q: could allocentric representations be explained via egocentric spatial reference frames?

Question 11

POTENTIAL ALLOCENTRIC TASK EFFECTS

Answer 11

• mental shift of objects to center it frontally (egocentric left-right decisions)
• mental rotation
• could mediate view-dependent object/scene recognition

Question 12

LIMBIC SYSTEM

Answer 12

• thalamus
• cingulate gyrus
• fornix
• amygdala
• hippocampus
• parahippocampal gyrus

Question 13

MORRIS ET AL. (1982)

Answer 13

• hippocampus lesions prior to training DON’T specifically impair working/reference memory BUT spatial task
• all rats showed same escape latency in 2nd experiment phase (cue-based navigation)
• reversal to hidden platform in 3rd phase = rats w/hippocampal lesions performed poorly again
• lesions after training = less strong effects; hippocampus ISN’T site for permanent memory storage

Question 14

O’KEEFE & DOSTROVSKY (1971)

Answer 14

• place cells in hippocampus; encoding of observer-independent spatial location
• populations of neurons (extracellular recordings of freely moving rats) w/dif spatial preferences in hippocampus; collectively said cells form spatial maps

Question 15

MULLER ET AL. (1987)

Answer 15

• place field maps; signal place recognition
• dif cells encode dif locations
• shape/size of firing fields vary
• not all complex spike cells act like place cells; preference can change in novel environment
• single cells can code for dif spatial locations in dif contexts firing w/varied patterns; may have dif patterns in same environment (ie. lights on/off)

Question 16

EICHENBAUM ET AL. (1987)

Answer 16

• place cells rely on spatial info derived from idiothetic cues
• vestibular activation/visual input from animal’s own movement modulate firing patterns of place cells
• place cells continue firing in dark (ie. when light switched off)
• rats trained to alternate turns; some place cells fired for location as expected BUT others fired location in conjunction w/anticipation of left/right turn to be made

Question 17

CAREW (2005)

Answer 17

• head direction cells fire w/directional pref maintained in familiar/novel environments
• head direction cells = location-invariant

Question 18

MOSER & MOSER (2007)

Answer 18

• coding representation of space
• grid cells (together w/other cells in entorhinal cortex that recognise direction of animal head/border of room) form networks w/place cells in hippocampus
• said circuitry constitutes comprehensive positioning system (aka. inner GPS) in brain; positioning system in appears to have similar components as those in rats

Question 19

TAUBE (2006)

Answer 19

AVH CELLS
- angular head velocity cells
- firing rate increases linearly as function of angular speed (ie. for both CW/CCW head turns in symmetrical AVH cells)
GRID CELL
- neuron that fires at multiple locations in environment; locations of high activity form repeating hexagonal grid-like pattern
HD CELLS
- head direction cells

Question 20

GOLGI’S METHOD

Answer 20

• staining neurons; revolutionised study of brains/neurons
  HIPPOCAMPAL FORMATION (MEDIAL TEMPORAL LOBE)
• dentate gyrus
• hippocampus proper (cornu ammonis)
• subiculum (incl. adjacent areas of parahippocampal gyrus (ie. presubiculum/parasubiculum/entorhinal cortex)

Question 21

LOPEZ-ROJAS & KREUTZ (2016)

Answer 21

• dentate gyrus filters incoming excitation from entorhinal cortex
• classical trisynaptic hippocampal circuit model of info processing (Anderson et al. (1971))
• parallel connectivity; entorhinal cortex projects to both CA1/CA3

Question 22

CAREW (2000)

Answer 22

• CA1/CA3 = major subdivisions in hippocampus
• CA = cornu ammonis (Ammon’s horn); pyramidal cell layers
• remarkably regular arrangement of soma/projections of principle neurons (pyramidal cells)
• can take slices from hippocampus that preserve functioning network

Question 23

TRISYNAPTIC CIRCUIT

Answer 23

1. connection from entorhinal cortex -> dentate granule cells via preforant path
2. connection from granule cells -> CA3 pyramidal cells via mossy fibers
3. connection from CA3 pyramidal cells -> CA1 pyramidal cells via Schaffer collaterals

Question 24

TSIEN ET AL. (1996)

Answer 24

• targeting NMDA receptor w/genetic tools
• LTP = normal in wild-type animals/controls (genetically engineered) BUT absent in NMDA knockouts

Question 25

MORRIS ET AL. (1986)

Answer 25

- Q: does hippocampal LTP have anything to do w/spatial learning? - APV = NMDA blocker - 8 days training w/hidden platform - day 9 = test w/o platform - same APV treatment also suppressed LTP

Question 26

SUMMARY (1)

Answer 26

- spatial info = important for beh - animals can find/learn routes & rely on egocentric ref frames - some animals (birds travelling over long distances/mice)/humans also form allocentric representations - hippocampus = major important for spatial learning/navigation in vertebrates BUT not exclusive role; other areas also involved

Question 27

SUMMARY (2)

Answer 27

- blocking NMDA receptors prevents LTP/spatial learning providing evidence for causal link - explanations for species/sex-based/individual dif = intuitive to human beh BUT can be influenced by researcher's confirmation/biases; experimental scrutiny/bias awareness/diversity = key to advance scientific knowledge