Altered functional connectivity of primary visual cortex in late blindness

Figures & data

Table 1 MNI coordinates for selected seed regions

ROI	Seed regions	x	y	z
1	L-V1	−8	−76	10
2	R-V1	8	−76	10
3	R-LGN	22	−30	−2
4	L-LGN	−18	−32	0
5	R-SC	2	−26	−6
6	L-SC	−2	−28	−6
7	R-Hipp	24	−3	−2
8	L-Hipp	−24	−3	−2

Note: MNI coordinates for vision-related nuclei.

Abbreviations: Hipp, hippocampus; L, left; LGN, lateral geniculate nucleus; MNI, Montreal Neurological Institute; R, right; ROI, region of interest; SC, superior colliculus; V1, primary visual cortex.

Table 2 Demographics and characteristics of late blindness

ID	Gender	Age (years)	Onset age	Preferred hand	Onset age of blindness (years)	Cause of blindness
1	Male	28	9	Right-handed	20	Retinitis pigmentosa
2	Male	35	8	Right-handed	16	Retinitis pigmentosa
3	Female	26	7	Right-handed	14	Retinitis pigmentosa
4	Male	21	10	Right-handed	14	Retinitis pigmentosa
5	Male	36	6	Right-handed	22	Retinitis pigmentosa
6	Female	26	9	Right-handed	20	Retinitis pigmentosa
7	Male	39	6	Right-handed	14	Retinitis pigmentosa
8	Male	28	10	Right-handed	13	Retinitis pigmentosa
9	Male	51	10	Right-handed	20	Retinitis pigmentosa
10	Male	50	8	Right-handed	22	Retinitis pigmentosa
11	Female	46	9	Right-handed	16	Retinitis pigmentosa
12	Male	34	12	Right-handed	27	Retinitis pigmentosa
13	Female	49	9	Right-handed	26	Retinitis pigmentosa
14	Male	54	10	Right-handed	30	Retinitis pigmentosa
15	Male	20	12	Right-handed	15	Retinitis pigmentosa
16	Female	28	10	Right-handed	22	Retinitis pigmentosa
17	Female	57	8	Right-handed	21	Retinitis pigmentosa
18	Female	62	11	Right-handed	16	Retinitis pigmentosa
19	Male	25	10	Right-handed	15	Retinitis pigmentosa
20	Male	29	10	Right-handed	15	Retinitis pigmentosa
21	Female	65	9	Right-handed	33	Retinitis pigmentosa
22	Female	61	11	Right-handed	16	Retinitis pigmentosa
23	Male	24	9	Right-handed	12	Retinitis pigmentosa
24	Female	53	9	Right-handed	21	Retinitis pigmentosa
25	Male	31	8	Right-handed	17	Retinitis pigmentosa
26	Male	37	9	Right-handed	12	Retinitis pigmentosa
27	Female	34	10	Right-handed	15	Retinitis pigmentosa
28	Male	41	5	Right-handed	17	Retinitis pigmentosa
29	Male	33	8	Right-handed	22	Retinitis pigmentosa
30	Female	35	10	Right-handed	19	Retinitis pigmentosa

Table 3 Significant differences in the FC of V1 between LB and SCs

Brain regions	BA	Peak t-scores	MNI coordinates (x, y, z)	Cluster size (voxels)
FC in left V1
Bilateral cuneus/lingual gyrus/calcarine	18/19/30	−5.567	9, −75, 6	1,280
Left precentral gyrus and postcentral gyrus	2/3/4	−4.183	−48, −24, 45	442
FC in right V1
Bilateral cuneus/lingual gyrus/calcarine	18/19/30	−5.503	−15, −72, 3	1,238
Left precentral gyrus and postcentral gyrus	2/3/4/6	−3.812	−60, −12, 33	422

Note: The statistical threshold was set at the voxel level with P<0.01 for multiple comparisons using Gaussian random-field theory (two-tailed, voxel-level: P<0.01, GRF correction, cluster-level: P<0.05).

Abbreviations: BA, Brodmann area; FC, function connectivity; GRF, Gaussian random field; LB, late blindness; MNI, Montreal Neurological Institute; SCs, sighted controls; V1, primary visual cortex.

Figure 1 Significant zFC maps of left V1 differences between two groups.

Notes: (A) Distribution mean zFC pattern of left V1 in group-level of LB and SC subjects in the typical frequency band (0.01–0.1 Hz). (B) Intragroup patterns of zFC maps of left V1 between two groups. (C) Significant zFC maps of left V1 differences between two groups (voxel-level: P<0.01, GRF correction, cluster-level: P<0.05).
Abbreviations: GRF, Gaussian random field; iFC, intrinsic functional connectivity; LB, late blindness; LH, left hemisphere; RH, right hemisphere; SCs, sighted controls; V1, primary visual cortex; zFC, z-values functional connectivity.

Figure 2 Significant zFC maps of right V1 differences between two groups.

Notes: (A) Distribution mean zFC pattern of right V1 in group-level of LB and SC subjects in the typical frequency band (0.01–0.1 Hz). (B) Intragroup patterns of zFC maps of right V1 between two groups. (C) Significant zFC maps of right V1 differences between two groups (voxel-level: P<0.01, GRF correction, cluster-level: P<0.05).
Abbreviations: GRF, Gaussian random field; iFC, intrinsic functional connectivity; LB, late blindness; LH, left hemisphere; RH, right hemisphere; SCs, sighted controls; V1, primary visual cortex; zFC, z-values functional connectivity.

Table 4 Abnormal rs-FC within the vision-related nuclei between two groups

ROI 1	ROI 2	P-values
L-V1	R-V1	0.000127
L-V1	R-SC	0.031
R-V1	L-Hipp	0.037

Note: rs-FC within V1 and vision-related nuclei between two groups.

Abbreviations: Hipp, hippocampus; L, left; R, right; ROI, region of interest; SC, superior colliculus; V1, primary visual cortex; rs-FC, resting state-functional connectivity.

Figure 3 Significant zFC maps of V1 and vision-related nuclei differences between two groups.

Notes: Visualization for abnormal rs-FC within V1 and vision-related nuclei between two groups (voxel-level: P<0.01, GRF correction, cluster-level: P<0.05). Red arrows denote increased FC; blue arrows denote decreased FC.
Abbreviations: FC, functional connectivity; GRF, Gaussian random field; Hipp, hippocampus; L, left; LB, late blindness; LGN, lateral geniculate nucleus; R, right; SCs, sighted controls; SC, superior colliculus; V1, primary visual cortex.

Figure 4 ROC curve analysis of the mean zFC values for altered brain regions.

Notes: (A) ROC curve in zFC in left V1: LB < SCs, for B-CUN/LGG/CAL 0.838 (P<0.001; 95% CI: 0.726–0.950); for L-PreCG/PostCG 0.838 (P<0.001; 95% CI: 0.733–0.944). (B) ROC curve in zFC in right V1: LB < SCs, for B-CUN/LGG/CAL 0.835 (P<0.001; 95% CI: 0.723–0.946); for L-PreCG/PostCG 0.804 (P<0.001; 95% CI: 0.691–0.916).
Abbreviations: AUC, area under the curve; B, bilateral; CAL, calcarine; CUN, cuneus; FC, functional connectivity; L, left; LGG, lingual gyrus; PostCG, postcentral gyrus; PreCG, precentral gyrus; ROC, receiver operating characteristic; V1, primary visual cortex.

Figure 5 Significant correlation was observed between the onset age of blindness and zFC values in the (A) left V1 (r=0.545, P=0.002) and (B) right V1 (r=0.543, P=0.002) in LB individuals.

Abbreviations: B, bilateral; CAL, calcarine; CUN, cuneus; FC, functional connectivity; L, left; LGG, lingual gyrus; R, right; V1, primary visual cortex.