Stability of human V1 retinotopy

measured with moving patterns

Junjie Liu

David Ress

Satoshi Nakadomari

Brian A. Wandell

Stanford University

V1 retinotopic organization

(Credit: J.C. Horton)

(deg)

Calcarine sulcus

Occipital pole

Human V1

Occipital pole

Calcarine sulcus

FMRI Measurement

Coherence

1.0

0.4

Eccentricity Map

20 deg

Occipital pole

From Science, 2003

Motion-dependent Responses

In

Time (sec)

Out0 12 24

· · ·

In vs. Out

We confirm data in Whitney et al.(Science, 2003).

But, these are merely responses to motion direction changes.

In Out

In Out

FM

RI

Sig

nal (

%)

Time (sec)0 12 24

0

-1

1

0

-1

1

Retinotopic representations

We measure:

In vs. Out does not measure retinotopic

representations.

In Blk In Blk · · ·

In vs. Blank

Retinotopic representations

We measure:

In vs. Out does not measure retinotopic

representations.

In Blk · · ·

In vs. Blank

Out

Time (sec)

Blk0 12 24

· · ·

Out vs. Blank

In Blk

Out Blk

No significant difference

Out vs. BlankIn vs. Blank

Coherence:1.00.4

Quantitative measurements (All voxels in V1)

In Blank

FM

RI

Sig

nal (

%)

Time (sec)

0

2

-2

-1

1

0 12 24

FMRI Amplitude: 2.1%

(Dougherty et al., 2003)

Distance measurement,Bins along calcarine

FM

RI A

mpl

itude

(%

)

Amplitude Profile

0 10 20 30 40 50

3

2

1

0

Cortical distance (mm)

In vs. Blank

posterior anterior

Stable retinotopic representations:

0 10 20 30 40 50

FM

RI A

mpl

itude

(%

)

3

2

1

0

Cortical distance (mm)

In vs. Blank

Out vs. Blank

“shift” model

0 10 20 30 40 50

FM

RI A

mpl

itude

(%

)

3

2

1

0

Cortical distance (mm)

In vs. Blank

Out vs. Blank

Shift

“edge” model

0 10 20 30 40 50

FM

RI A

mpl

itude

(%

)

3

2

1

0

Cortical distance (mm)

In vs. Blank

Out vs. Blank

Asymmetricaledge response

In vs. Out: Responses to motion direction

changes

0 10 20 30 40 50

FM

RI A

mpl

itude

(%

)

3

2

1

0

Cortical distance (mm)

In vs. Out

Three independent measurements

0 10 20 30 40 50

FM

RI A

mpl

itude

(%

)

3

2

1

0

Cortical distance (mm)

In vs. Blank

Out vs. Blank

In vs. Out

(In vs. Out) > (In vs. Blank) – (Out vs. Blank)

Responses to motion direction changes

Differences between retinotopic

representations

0 10 20 30 40 50

FM

RI A

mpl

itude

(%

)

1

0

Cortical distance (mm)

(In vs. Blank) – (Out vs. Blank)In vs. Out

Retinotopy is Stable

• We confirm the (In vs. Out) measurements.

• Additional measurements (e.g., In vs. Blank), show that retinotopic representations do not shift, or shift very little, with stimulus motion direction.

• Hence, this stimulus manipulation has negligible impact on estimated retinotopic maps.

Out vs. BlankIn vs. Blank

In vs. Out

Thank you!