Download Location of macaque MT

Cytochrome
Oxidase blobs
in V1
V2 Striping pattern in cytox
V1 contains
direction
selective cells
Many are in IVB
Direction Selectivity
V1 input-output flow
Visual Cortex
Can Be
Subdivided
into Multiple
Distinct
Visual Areas
Based on
Maps and
Other
Criteria
(Van Essen et al.,
Vision Research,
2001)
Macaque visual areas
Macaque visual
cortex is very
extensive and much
of it is buried in
sulci. Its extent is
best appreciated
when the brain is
cut horizontally. In
this view, several
visual areas can be
identified.
V5 receives
input from the
thick stripes in
V2
Motion
selective
neurons in
IVB
project to
and MT/V5
The
direction
selective
cells in V5
are
organized
into a spatial
map
Functional MRI
• Non-invasive, measures
an intrinsic signal
• Spatial
• resolution
• localization
~ 5 mm
~ 1-2 mm
• Temporal
• resolution
• localization
~ 5 sec
~ 200 ms
• Can study individual
subjects in detail
fMRI Methods
GE 3.0T MR scanner
Head Coil
FMRI Measures Local Changes In Blood
Oxygenation, An Indirect Measure of
Neural Activity
fMRI response
Example of motion sensitivity in human MT+
4
2
0
-2
-4
0
36
72
108 144 180 216
Time (sec)
R
L
Comparison of V1 and MT+ Responses
Signal Processing Should Account For
Cortical Topology
(a)
(b)
Widely Used Visualization Methods Do
Not Respect Cortical Topology
(a)
(b)
Different Visualizations Are Used
Commonly
PO-s
Dorsal
IP-s
PO-s
Ca-s
Lateral
Medial
Li-g
Ca-s
ST-s
Fu-g CoL-s
Li-g
Fu-g
Col-s
Ventral
Visual Cortex Contains Several Maps of
The Visual Field: V1 Is Illustrated
Upper VM
HM
Lower VM
80
Traveling Wave In V1
Phase-Encoded Retinotopies
(Engel et al., 1994,1997)
Eccentricity
Maps
20 deg
(Folded
Representation)
SH/081798
Eccentricity Map
Flattened Representation
20 deg
60 mm radius unfold
V1
V2d
V3d
WAP