0
fMRI response amplitude (% change)
0.75Atlas-defined V1
S04
A widespread task-related hemodynamic response in human V1 is modulated by task difficultyMinyoung Ryoo1, Charlie S. Burlingham2*, Zvi Roth1, Saghar Mirbagheri2, David J. Heeger2,3 & Eli Merriam1*
1 Laboratory of Brain and Cognition, NIMH. 2 Department of Psychology, New York University. 3 Center for Neural Science, New York University.
Task-related hemodynamic responses:
• Endogenous responses in the absence of a visual stimulus at the earliest stages of visual cortical processing.
• Spatially global and entrained to task timing.
Background
Easy
10 15Time (s)
-0.1
0
0.2
-0.1
0
0.2CorrectIncorrect
50
N = 13
***
Hard
10 1550
N = 13
CorrectIncorrect
**
*** p < .001** p < .005* p < .05 Modulation index =
(Δeasy - Δhard) / (|Δeasy| + |Δhard|)
V1, Ispilateral hemisphere: widespread hemodynamic activity unrelated to visual stimulus or spatial attention
Experimental ProtocolLow Reward
0
• Orientation discrimination task; tone feedback.
• Separate runs (of 15 trials) for four conditions (easy vs. hard, low reward vs. high reward).
Conclusions
• Task-related responses entrained to task timing.
• Pupil dilation also modulated by difficulty, reward, and correct/incorrect feedback.
-> Task-related responses reflects arousal.
*Email: [email protected], [email protected], [email protected] by: NEI grant R01EY025330 (to E.M. & D.H.) and NIMH Intramural Reseach Program.Thanks to: Aniruddha Das.
fMRI responses in ipsilateral V1:
Pupil responses:
Task Difficulty
N = 5
160
Time (s)
0
Pup
il ar
ea (A
U)
0 2 4
***
-80
160
0
-80 N = 5
0 2 4
*
Low Reward
10 15Time (s)
-0.1
0
0.15
fMR
I res
po
nse
(% c
hang
e)
CorrectIncorrect
50
N = 9
10 15
-0.1
0
0.15
5
N = 9
*
High Reward*** Correct
Incorrect
Inco
rrec
t -
corr
ect
amp
litud
e (s
td)
Easy Hard
S01 S02 S05S03 S04 S09S06 S07 S08
0
0.1
0.2
0.3
S11 S12 S13
fMR
I res
po
nse
(% c
hang
e)
RewardfMRI responses in ipsilateral V1:
Pupil responses:
S14 S15 S18S16 S17
0
20
40
60
***
All
0.5
0
Mo
dul
atio
n in
dex
S19 S02 S04 S21S06 S20 S10
0
.025
.05
S11 S22
Low High
All
0
-0.5
All
0.2
-0.3
0
0
1
All
1
0
S19 S01 S20S04 S06 S13S10 S21 S11 S22 S23
0
10
20
30
-250
125
-250
125
Pup
il ar
ea (A
U)
Time (s)0 2 4 0 2 4
***
~90% correct stakes: $0.25 Easy
N = 11N = 11
Are task-related hemodynamic responses modulated by task difficulty and reward?
Are they linked to arousal?
Aim
Four
ier
amp
litud
e
0.1 0.2 0.30
0
0.1
0.2
Task frequency (1/15 Hz)
Frequency (Hz)1000
fMR
I res
po
nse
(% c
hang
e)
200
0
-0.3
0.3
Time (s)
Trial onsets
ITI 15 s
Stimulus 200 ms
or
Hard~70% correct stakes: $1.10
High Rewardor
