1. Emotional & Spatial Learning in goldfish is dependant on different telencephalic pallial systems
M. Portavella & J. Vargas
European Journal of Neuroscience
Vol. 21, pp , 2005
Morris 1981
Rodrigo 2002
Portavella et al 2004 a, b

2. How big of a nerd am I?

5. Objectives
Test the effects of specific lesions on different learning capacities and explore the existence of differentiated learning and memory systems in fish
Establish homologies between pallial areas of both fish and other vertebrates

6. Which part of the telencephalon are you?
Hippocampus
Spatial, relational, contextual learning
Amygdala
Emotional learning, ‘nose brain’
Mammals, birds and reptiles
Not so clear if the divisions exist so clearly in the fish
Most lesion studies are entire telencephalon
Impairs aggressive and reproductive behaviors

8. DG Entorhinal Cortex CA3 Damage to any One specific area
Mossy
fiber
Entorhinal
Cortex
CA3
Schaffer
collateral
Damage to any
One specific area
Can affect new memory
Acquisition
CA1
Sub

9. Development of the Telencephalon
Eversion in teleost fishes
Evagination in land vertebrates

10. Lateral Telencephalic Pallium LP
Ablation of LP impairs spatial learning in T-maze

11. Medial Telencephalic Pallium MP
Ablation of MP impairs two way avoidance conditioning
Ablation of MP and LP negatively affect trace conditioning

12. Learning: process by which new information is used to modify subsequent responses
Memory: using processed information to modify
subsequent behavioral responses
Not directly measurable, inferred from changes in
Behavior over time
enter the behavioral models….

13. Spatial Learning Navigate through space to a discrete goal
Cartographic Strategy: navigation based on cognitive map
Integration of positional information derived from different views of environment at different times
Positioning vectors
Egocentric- specify landmarks in a body-centered coordinate system (relative to me)
Geocentric- specify my location in earth centered coordinates

14. The animal’s geocentric position vector is computed by the dead-reckoning mechanism. The egocentric position vector for the landmark – its direction (or bearing, β) and distance from the animal–is computed by the animal’s perceptual system. Rotating the egocentric vector by the animal’s geocentric orientation (its heading, η ) gives a vector of the same length with orientation η+β (heading+bearing). Adding
that vector to the animal’s geocentric position vector ag gives the landmark’s position in the geocentric coordinate framework

15. Morris Water Maze 1980 ish

16. Way Cool Michael Jordan Poster
Use landmarks and extra-maze cues to find platform located underwater
Perform worse if cues are mixed up
No effect if some cues are removed
No effect if maze is rotated
Learning is based on spatial relationships between landmarks

17. Spatial Learning Task used in this study
Pre exposure to box with all doors open
Acquisition phase = 25-trials/session daily
Error scored if fish bumped into glass plate
Correct choice scored if fish swims into correct exit
80% correct choices in 25 trials = learning criteron

18. Once learning criteria were met, fish were exposed
to reversal training, where goal was moved to other side
Of the tank. Same criteria for learning, 80% correct/25 trials

19. The Shocker

20. 2-Way Avoidance: shuttlebox
3 days of pre exposure, with no shock or lights
Daily session of 10 trials separated by 1-2 min for 20d
5 mins pre and post session acclimation
CS (discriminative stimulus; green light) for max 15 s
If fish escapes within 10 s, no shock delivered
If no response within 10 s, shock for a max of 5 seconds
Thus, 10 s of temporal separation btwn shock and CS

21. Responses classified in 2 categories
Avoidance response: escape within 10 s
Escape response: escape between s

22. Subjects 24 pet shop grade goldfish 3 experimental groups
LP (lateral pallium ablation) n=8
MP (medial pallium ablation) n=8
Control
Surgery but no ablation n=4
No surgery n=4

23. Surgery
Fish were anaesthetized and placed in surgical chamber, with constant flow or doped water over gills
Skull was opened and offending brain tissue was sucked out with a micro pipette driven by a vacuum
5 days recovery in home tank
Following experiments all brains were removed to verify ablation

24. Timeline Spatial task 2 way avoid 5 days rest Death. Brains fixed and
Checked for albation
accuracy
Surgery
4 surgery controls
4 non-surgery controls
8 LP
8 MP

26. Results: Avoidance Task
No diff between non-treated and sham controls, so they were grouped
MP group show lower level of avoidance responses compared to LP & Control

28. Results MP lesion group show escape
LP and control groups show avoidance

30. Results: Spatial Learning Task
No diff between groups in # of trials it takes to acquire spatial task
During reversal, LP lesion group requires more sessions to reach learning criteria, compared to original acquisition phase
P< .07 compared to MP group session #

31. *

32. Results
No diff between groups in # of errors scored in initial learning phase
During reversal, LP lesion group had significantly more errors than it did in the first learning trials

33. *

34. Discussion
Lesions of the Medial Pallium impair acquisition of an avoidance conditioning response
Similar to whole telencephalic lesion
Amygdalar lesions in land vertebrates produces same result
No effect on spatial learning or reversal

35. Cause deficits in spatial learning however
Lesions of the Lateral Pallium have no effect on acquisition of an avoidance conditioning response
Cause deficits in spatial learning however
More sessions necessary during reversal
More errors accrued during reversal
Less efficient in reversal
But they still did reverse
It was pretty easy

36. Differences in learning systems?
Cartographic vs Taxon Learning system
Taxon- can not detect changes in an environmental cue set, learn each time de novo
LP lesion fish using taxon system?
Cartographic- detect changes in the relations between environmental cues, facilitates re- learning of a task
MP and Control using cartographic system
I think this is bogus
Incomplete ablation
Help from other regions

37. MP lesion and pain
MP fish show escape from shock behavior in two way avoidance, but swim out within .5 to 1s after shock onset
The shock still hurts
No effect of MP lesion on pain tolerance
Or locomotion

38. Importantly, these results support the existence of different telencephalic based learning systems in a teleost
Support the homology hypothesis on functional features between mammalian and fish models