Locating perceptual learning within the hierarchy of visual

areas

Geoff GhoseUniversity of Minnesota

Departments of Neuroscience and PsychologyCenter for Magnetic Resonance Research

Macaque Visual Cortex

(Felleman and Van Essen 1991)

Visual Cortex Hierarchy

V1

7a

PIT

CIT

AIT

TEO

VP

V4

MT

DP

V2

V4

MST

VIP

LIP

Low HighPreferred Stimulus Complexity

Receptive Field Size

Learning in V1?

• somatosensory and auditory map changes with training

• adult plasticity seen with retinal lesioning

• psychophysical experiments in which training effects were retinotopically specific

Training History

Orie

nta

tio

n C

ha

ng

e (

de

g)

Naive Humans

J Neurophysiology 2002

Trained

Trained

Opticnerve

Opticchiasm

Optictract

Opticradiation

LGN

V1

Control

V1 Hypotheses

Example Cell

V1 Expansion

45

Orientation

Preferred Orientation Distribution

Preferred Orientation (deg)

Trained

Location (N=139)

Untrained

Location (N=180)

0 45 90 1350

0.1

0.2

Pro

port

ion o

f C

ells

0 45 90 1350

0.1

0.2

V1 Refinement

45

Orientation

Orientation Bandwidth

0 45 90 1351800

50

Bandw

idth

(deg)

0 45 90 1351800

50

Trained Location

N=139

Preferred Orientation (deg)

Untrained Location

N=180

Orientation4545

Resp

onse

V1 V2Expansion no no

Preferred Orientation no no

Visuotopic Magnification no no

RefinementOrientation Bandwidth no no

Maximum Response no no

Tuning Amplitude no no

Response Variance no no

Receptive Field Size no no

Preferred Spatial Frequency no no

Orientation Relative to Preferred

No

rma

lize

d R

esp

on

se

0

1

-90° -45° 0° 45° 90°

Fig 16

Trained

(N=266)

Untrained

(N=215)

Orientation Discrimination Training in V4

(Yang and Maunsell 2004)

Perceptual learning in V1?Electrophysiology

Task Receptive Field Effect

Crist et al. (2001) Line Bisection Surround Only

Schoups et al. (2001)

Orientation Discrimination Orientation Tuning

Ghose et al. (2002)

Orientation Discrimination

Decrease in trained stimulus representation

Perceptual learning in V1?fMRI

Task Signal from Trained Stimuli

Schwartz et al. (2002) Texture Detection Increase

Furmanski et al. (2004)

Orientation Detection Increase

Sigman et al. (2005) Visual Search Increase

Kourtzi et al. (2005) Shape Detection Increase, No effect

(Kourtzi, Betts, Sarkheil, Welchman 2005)

Shape Analysis after LearningLow Salience

High Salience

Visual Hierarchy and Spatial Attention

V1

0.5

0.0

TEOMTV4V3AV3V2

Atte

ntio

n M

odul

atio

nIn

dex

(O’Connor, Fukui, Pinsk, Kaster 1989)

(Kourtzi, Betts, Sarkheil, Welchman 2005)

Shape Analysis after Learning

(Kourtzi, Betts, Sarkheil, Welchman 2005)

Positive Correlation between V1 Activity and Performance

Negative Correlation between V1 Activity and Performance

(Sigman et al. 2005)

Task Specific Orientation Learning

0 45 90 135 180

10

20

30

40

50

Discrimination Response Pooling

50%

100%

75%

Perf

orm

ance

Orientation (deg)Orienta

tion D

iffe

rence (

deg)

0 45 90 135 180

10

20

30

40

50

Behavior

0 45 90 135 180

10

20

30

40

50

Discrimination Detector Pooling

0 45 90 135 180

10

20

30

40

50

Stimulus Classification Response Pooling

Language as a representational hierarchy

?reisae yna siht sI

Visual Cortex Hierarchy

V1

7a

PIT

CIT

AIT

TEO

VP

V4

MT

DP

V2

V4

MST

VIP

LIP

Low High

Preferred Stimulus Complexity

Representation Plasticity

Attentional Modulation