SUPPLEMENTARY MATERIAL
The following document contains supplementary tables and figures to the article
“Individual Differences in Impulsive Action Reflect Variation in the Cortical Serotonin 5-
HT
2A
Receptor System” (Fink, LHL et al .).
Supplementary Tables
LI MI HI
Accuracy (% )
Reinforcers Earned
Premature
Omissions
Latency to Reinforcer
Avg SEM
94.8 1.7
26.2 0.8
60.5 1.6
11.9 1.3
1.61
0.08
Avg SEM Avg SEM
96.1 1.3
24.3 0.7
96.3 1.1
20.6
* #
1.1
67.2
*
0.6 74.4
* #
1.5
7.5
*
0.7 4.2
* #
0.8
1.72
0.13
1.45 0.09
Average performance of LI ( n= 8), MI ( n= 13), and HI ( n= 8) rats during two ITI8 challenge sessions.
* p <0.05 vs. LI
# p <0.05 vs. MI

Fink, Latham HL et al 5-HT
2A
Receptor in Impulsive Action
Table S2. Comparison of stable HI and LI performance in the 1-CSRT task across five cohorts of outbred
Sprague-Dawley rats
LI (n = 7-8/cohort)
Cohort 1
(mean +/- SEM)
Cohort 2
(mean +/- SEM)
Cohort 3
(mean +/- SEM)
Cohort 4
(mean +/- SEM)
Cohort 5
(mean +/- SEM)
Premature Responses
(F
4,32
= 2.43, n.s.)
Reinforcers Earned
(F
4,32
= 0.76, n.s.)
22.5
70.6
± 1.5
± 2.3
(F
Accuracy
4,32
= 1.04, n.s.)
98.5 ± 0.4
16.0
72.0
98.1
± 1.9
± 1.7
± 0.7
22.4
69.1
97.7
± 1.3
± 2.7
± 0.8
19.4
74.1
98.7
± 2.6
± 3.0
± 0.4
21.9
73.5
99.2
± 1.6
± 1.4
± 0.4
% Omissions
(F
4,32
= 2.55, n.s.)
5.5 ± 1.9
10.4 ± 1.8
7.0 ± 1.6
5.3 ± 1.4
4.1 ± 0.4
HI (n=7-9/cohort)
Cohort 1
(mean +/- SEM)
Cohort 2
(mean +/- SEM)
Cohort 3
(mean +/- SEM)
Cohort 4
(mean +/- SEM)
Cohort 5
(mean +/- SEM)
Premature Responses
(F
4,32
= 1.33, n.s.)
Reinforcers Earned
(F
4,32
= 0.92, n.s.)
31.8
64.1
± 3.9*
± 4.1
24.4
70.1
± 2.2*
± 2.1
30.6
64.5
± 2.4*
± 3.0
27.9
68.3
± 2.2
± 2.4
# 28.6
66.4
± 1.5*
± 1.5
Accuracy
(F
4,32
= 0.60, n.s.)
97.8
± 0.7
97.7
± 0.5
98.5
± 0.6
97.1
± 0.6
97.9
± 0.7
% Omissions
(F
4,32
= 1.81, n.s.)
2.9 ± 0.6
3.8 ± 0.6* 4.0 ± 0.8
1.8 ± 0.4
3.6 ± 0.6
Average performance measures of HI and LI rats during stable ITI5 maintenance sessions. * p <0.05 vs . LI within each respective cohort. # p =0.06 vs . LI within respective cohort.
2

Fink, Latham HL et al
Supplementary Figures
5-HT
2A
Receptor in Impulsive Action
Figure S1. Following 1-CSRT task training and phenotypic identification, the effects of
DOI (0.01, 0.03, and 0.1 mg/kg) were evaluated under ITI5 conditions. A) In HI rats, DOI significantly decreased reinforcers earned at 0.03 mg/kg and 0.01 mg/kg (# p <0.05 vs .
HI-VEH). In LI rats, DOI significantly decreased reinforcers earned at only the 0.03 mg/kg dose (
* p <0.05 vs . LI-VEH). B) A significant effect of phenotype on omissions was observed ( F
1,15
= 11.94, p <0.01), however DOI had no effect on omissions.
3

Fink, Latham HL et al 5-HT
2A
Receptor in Impulsive Action
Figure S2. Following 30 min pretreatment with vehicle (VEH) or M100907 (0.001, 0.01, and 0.1 mg/kg), rats were evaluated in the 1-CSRT task under ITI5 conditions. A)
Following vehicle treatment, HI rats tended to earn few reinforcers than LI rats ( n.s.
).
M100907 increased reinforcers earned in HI (0.1 mg/kg; # p <0.05 vs . HI-VEH), but not LI rats ( n.s
.). B) Administration of M100907 did not significantly alter omissions in the 1-
CSRT task. LI rats tended to omit more trials than HI rats (main effect: F
1,14
= 4.54, p =0.051), and M100 tended to increase omissions (main effect: F
3,42
= 2.58, p =0.06).
However, no treatment × phenotype interaction was observed ( F
3,42
= 0.27, n.s.
). Except at the highest dose tested (0.1 mg/kg M100907), omissions were well below criterion for stable performance (<20).
4

Fink, Latham HL et al 5-HT
2A
Receptor in Impulsive Action
550
40
500
LI
MI
HI
30
450
20
400
10
350
r = 0.508
p < 0.01
300 0
10 15 20 25 30 35 40
LI HI
Figure S3. A ) Cortical [ 3 H]-ketanserin binding correlates with premature responses under ITI5 conditions ( see Figure 4A ), with phenotypic identification of individual rats as determined by ITI8 challenge (LI – open circles, MI – grey circles, and HI – closed circles). Following phenotype stratification by ITI8 challenge, unusually high premature responses in a single LI rat weakened B ) the difference in premature responses between LI ( n =7, white bar) and HI rats ( n =8, black bar) under ITI5 conditions ( p= 0.06).
5

Fink, Latham HL et al 5-HT
2A
Receptor in Impulsive Action
5
4
3
2
1
0
LI HI
Figure S4 . No difference in Htr2A mRNA expression in the mPFC was observed between LI (white bar, n =7) and HI (black bar, n =7) rats. Htr2A mRNA abundance was evaluated in triplicate by qRT-PCR and normalized to the housekeeping gene cyclophilin.
Data are presented as normalized crossing threshold (ΔC
T
).
6

Fink, Latham HL et al
Supplementary Materials and Methods
5-HT
2A
Receptor in Impulsive Action
Htr2a transcript quantitation . Reverse transcription was performed using SuperScript III
First Strand Synthesis System (Life Technologies) with random hexamer primers. RT-
PCR reactions were assayed in triplicate on a 7500 Fast RT PCR System using TaqMan
Fast Advanced Master Mix and TaqMan gene specific primer/probes [ Htr2a :
Rn00568473_m1; Cyclophilin A ( Ppia) : Rn00690933_m1; Life Technologies]. Data were analyzed in terms of Crossing Threshold (Ct), for which ΔC
T
=C
T
( Htr2a ) –C
T
( Ppia )
(Anastasio et al , 2014).
7