Transcript buzsaki-banbury-2009

Different coding schemes in
dorsal and ventral hippocampus
Sebastien
Royer
Jagdish Patel
rodent
primate
cortex
cortex
D
V
A
Space representation
Other-than-space representation
P
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
water port
open field
7-arm radial
zig-zag maze
Absence of place cells in the ventral hippocampus?
Dorsal CA3
Ventral CA3
1m
Discrete place fields, high peak
firing rates
Large, diffuse or multiple peak
firing fields, low peak firing rates
Absence of place cells in the ventral hippocampus?
Field size (# pixels)
% area
Field size (contour)
% area
spatial information
stability
(R: first half/second half)
bits
Dorsal CA3 neurons have small, single,
direction-specific place fields
(as in McNaughton, Barnes, O’Keefe, Brain Res, 1983)
n e u r o n
#
1
329
Ventral CA3 neurons fire on multiple-arms, in a
direction-specific manner
vCA3 neurons fire on multiplearms
% of arms
# of active arms
vCA3 neurons are more
direction-specific than dCA3
% of cells
vCA3
r
Ventral CA3 neurons are arm type-specific
(only on reward-bound journeys)
Ventral CA3 population increases
firing rate on reward-bound travels
dorsal CA3
ventral CA3
Ventral CA3 neurons in the zig-zag maze
respond to local geometrical features
dorsal CA3
ventral CA3
right journey
right journey
Firing fields of vCA3 neurons are larger and
less directional
left journey
Firing patterns of vCA3 neurons in the zig-zag
maze reflect distances from the goal
vCA3
vCA3
R
L
R
L
int
Paucity of theta oscillations in ventral hippocampus
Paucity of theta-rhythmic vCA3 neurons
dCA3 pyramidal cells
1313
vCA3 pyramidal cells
162
dCA3 interneurons
107
vCA3 interneurons
35
Fewer vCA3 neurons show phase precession
vCA3 pyramidal cells
dCA3 pyramidal cell
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
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
CA1
mol layer
CA1
mol layer
CA1
Li, Somogyi, Ylinen, Buzsaki, J comp Neurol 1994
Differential CA3
projections
(ventral CA3
strongly projects
to granule cells)