Supplementary material
Supplementary Figure S1. Average (A) scotopic and (B) photopic ERG and VEP waveforms an hour
after IOP was returned to baseline (10 mmHg). These were elicited by the same flash intensity as in
Figures 1 and 3, respectively, of the manuscript. Both control (gray traces) and IOP-treated waveforms
(black traces) taken at the initial baseline (thin traces) and at one hour after cessation of the IOP
challenge (bold traces), were comparable. The exception being the photopic ERG (Fig. (B) left panel),
the potential reasons for which are discussed in the main text.
Page 1 of 4
Supplementary Figure S2. (A) Schematic ‘occlusion’ configurations to determine retinal contributions to
the pigmented rat full-field flash VEP. Occlusion was achieved via non-invasive (i.e. dim flash sub-VEP
threshold, -5.93 log cd.s.m-2) or invasive means (i.e. pharmacological blockade). Unfilled eyes;
unoccluded, filled eyes; occluded, cross; VEP measurement location; thick solid and dashed afferents;
retinostriate contributions from stimulated contralateral and ipsilateral eyes, respectively, thin afferents;
those that are blocked, horizontal arrows; potential inter-hemispheric influences. Line thickness
represent relative amount of contribution given the occlusion configuration. (B) Representative ERG and
STR (inset) waveforms illustrating the effect of each drug used for uni- and bilateral retinal blockade.
ERG effects are in agreement with literature.1-4 Briefly, pre- and post-cannulated test flashes (0.24 log
cd.s.m-2) confirmed that the ERG remained normal within test/retest variability. BaCl2 (inset, thick trace)
inhibits the inner retinal STR (-4.99 log cd.s.m-2, vs. untreated, inset thin trace). PDA and APB block
OFF- and ON-bipolar cell output (1.52 log cd.s.m -2), respectively. Only the photoreceptoral negativity
Page 2 of 4
remained when ‘All’ agents are injected (thick trace). Thus there should be no retinal output. (C) Average
monocular VEP waveforms recorded following unilateral retinal block with BaCl2 (n = 7). The
contralateral VEP (cortical response from the control eye, thin black trace) was markedly larger (~ 2 to
2.5 times) than the ipsilateral VEP (from BaCl2-treated eye, thick black trace), as have been previously
reported.5-7 Also included is the putative binocular VEP (gray trace) calculated post hoc. (D) Comparison
of non-visual cortical (thick traces) and ipsilateral retinal contributions (thin traces) to the VEP. Average
signals generated after bilateral injection of a drug combination that blocks retinal output from both eyes
(bilateral APB/PDA/BaCl2, n = 6), as well as extrapolated from cortical recording to a sub-VEP threshold
flash (-5.93 log cd.s.m-2, n = 7). Cortical responses from both methods were significantly smaller than the
ipsilateral retinal VEP. (E) Summary of VEP amplitudes (mean ± SEM, P1N1 and N1P2, see legend)
from the various isolation methods described. Average values are provided in Table S1. (F) Comparison
of relative contribution of remnant ipsilateral eye vs. non-visual cortical waveforms (see legend). P1N1
and N1P2 amplitudes are shown as a percentage of their respective controls for each group (mean ±
SEM). Ipsilateral waveform amplitudes (from unilatateral BaCl2) were significantly larger than those of
non-visual cortical noise (binocular dimmest flash and bilateral drugs). Arrows; putative visual P1N1 and
N1P2 proportions from the ipsilateral eye.
Supplementary Table S1 - Summary of the VEP parameter amplitudes and implicit times (mean ±
SEM) recorded from the approaches described in Figure S2 to examine relative monocular
(contralateral, ipsilateral) and non-ocular contributions to the binocular VEP. Scotopic 1.52 log
cd.s.m-2, unless stated otherwise.
Amplitude (µV)
P1N1
N1P2
P1
N1
P2
280  13
439  15
23  2
34  1
73  4
Contra-eye VEP (contra-BaCl2 control)
273  11
414  12
21  2
35  1
70  3
Ipsi-eye VEP (contra-BaCl2)
112  23
171  28
18  2
45  5
77  7
29  6
49  12
23  3
44  6
76  7
Non-visual signal (bilateral drugs)
40  8
56  11
25  5
49  6
76  7
Contra-eye VEP, photopic (contra-BaCl2 C)
143  15
135  16
21  2
47  2
65  3
Ipsi-eye VEP, photopic (contra-BaCl2)
44  10
61  9
29  4
46  2
63  3
Binocular VEP
(putative‡)
Non-visual signal
‡
Implicit time (ms)
(dim†)
From post hoc addition of monocular contralateral and ipsilateral waveforms.
† VEP
contralateral to the untreated control eye under scotopic conditions elicited with a -5.93 log cd.s.m-2 flash.
Supplementary Table S2 – Summary of VEP amplitude comparisons between visual and nonvisual signals described in Figure S2 and Table S1. Signals measured under scotopic conditions.
Binocular
VEP‡
ContraVEP
Contra-eye VEP (contra-BaCl2 control)
ns
-
Ipsi-eye VEP (contra- BaCl2)
*
*
-
Non-visual (bilateral drugs)
*
*
*
-
Non-visual (dim†)
*
*
*
ns
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IpsiVEP
Non-visual
(bilateral drugs)
Non-visual
(dim†)
-
‡ From
† VEP
post hoc addition of monocular contralateral and ipsilateral waveforms.
contralateral to the untreated control eye under scotopic conditions elicited with a -5.93 log cd.s.m-2 flash.
* indicates p < 0.05; paired, two-tailed T-test.
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