1. Different coding schemes in dorsal and ventral hippocampus
Sebastien Royer
Jagdish Patel

2. rodent primate cortex cortex P D V A Space representation
Other-than-space representation

3. Extrapolation from existing data
dMEC
Prediction: giant place fields in VH
small ?
larger ?
Jung et al. Hippocampus (1994)
Hafting et al. Nature 2005
Maurer, Vanrhoads, Sutherland, Lipa, McNaughton, Hippocampus 2005
Hafting et al. Science 2008

4. water port
7-arm radial
zig-zag maze
open field

5. Absence of place cells in the ventral hippocampus?
Dorsal CA3
Ventral CA3
Large, diffuse or multiple peak firing fields, low peak firing rates
1 m
Discrete place fields, high peak firing rates

6. Absence of place cells in the ventral hippocampus?
Field size (# pixels)
% area
Field size (contour)
% area
stability
(R: first half/second half)
spatial information
bits

7. Dorsal CA3 neurons have small, single, direction-specific place fields
(as in McNaughton, Barnes, O’Keefe, Brain Res, 1983) 1
neuron #
329

8. Ventral CA3 neurons fire on multiple-arms, in a direction-specific manner

9. vCA3 neurons fire on multiple-arms
% of arms
# of active arms
vCA3 neurons fire on multiple-arms
% of cells r
vCA3 neurons are more direction-specific than dCA3

10. Ventral CA3 neurons are arm type-specific (only on reward-bound journeys)

11. Ventral CA3 population increases firing rate on reward-bound travels
dorsal CA3
ventral CA3

12. Ventral CA3 neurons in the zig-zag maze respond to local geometrical features
dorsal CA3
ventral CA3

13. Firing fields of vCA3 neurons are larger and less directional
right journey
right journey
left journey

14. Firing patterns of vCA3 neurons in the zig-zag maze reflect distances from the goal

15. Paucity of theta oscillations in ventral hippocampus

16. Paucity of theta-rhythmic vCA3 neurons
dCA3 pyramidal cells
vCA3 pyramidal cells
1313
162
dCA3 interneurons
107
vCA3 interneurons 35

17. Fewer vCA3 neurons show phase precession
vCA3 pyramidal cells
dCA3 pyramidal cell

18. Differences between vCA3 and dCA3
vCA3 neurons fired on multiple arms of the radial maze
firing fields of vCA3 often formed a ring (similar mechanisms in each arm)
vCA3 neurons differentiated between open and closed arms in the radial maze.
Both arm type differentiation and arm segment generalization (ring) of v CA3 depended on the direction of travel
vCA3 neurons showed mirror-symmetric firing patterns in the zig-zag maze (distance from the goal)
cone-shaped place fields were exceptionally rare in vCA3
LFP theta power in vCA3 was smaller than in dCA3
Only a small fraction of vCA3 pyramidal cells and interneurons showed theta rhythmicity
Only a small fraction of vCA3 neurons showed phase precession

19. Hypothesis: Ventral hippocampus in the rat is functionally similar to pes and body of the primate hippocampus Dorsal hippocampus may be functionally similar to the tail
tail
pes/uncus
body VH

20. Li, Somogyi, Ylinen, Buzsaki, J comp Neurol 1994
CA1
Differential CA3 projections (ventral CA3 strongly projects to granule cells)
mol layer
CA1
mol layer
CA1
Li, Somogyi, Ylinen, Buzsaki, J comp Neurol 1994