Altered Spontaneous Brain Activity Patterns in Patients After Lasik Surgery Using Amplitude of Low-Frequency Fluctuation: A Resting-State Functional MRI Study

Figures & data

Figure 1 Typical fundus photographs of myopia patients before and after surgery.

Table 1 Demographics and Visual Measurements Between PRL and POL Groups

Condition	Lasik-Pre	Lasik-Post	t	P-value
SE-L (diopter)	−10.75±2.75	−0.75±0.25	8.764	0.023
SE-R (diopter)	−11.00±3.25	−0.50±0.25	9.437	0.016
Astigmatism-L (diopter)	−2.50±0.50	−0.25±0.25	5.182	0.044
Astigmatism-R (diopter)	−2.25±1.00	−0.50±0.25	4.032	0.047
Color Vision	15R	15R	N/A	>0.99
Confrontation Visual field	15R	15R	N/A	>0.99

Notes: 2-sample t-test between the same patients before and after the Lasik surgery; Data presented as mean±standard deviation.

Abbreviations: L, left; N/A, not applicable; R, right; SE, spherical equivalent.

Table 2 Brain Areas with Significantly Different ALFF Values Between Groups

Brain Areas	MNI Coordinates			BA	Number of Voxels	T value
	X	Y	Z
Lasik-post>Lasik-pre
ParaHippocampal_L	−24	−6	−27	36	59	6.6240
Vermis_1_2	3	−42	−24	0	27	7.8057
Cingulum_Post_L	−3	−33	30	23	37	5.7116
Lasik-post<Lasik-pre
SupraMarginal_L	−63	−51	24	22	17	−5.4842
Frontal_Inf_Tri_R	45	24	21	48	17	−6.8269

Note: The statistical threshold was set at the voxel level with P<0.05 for multiple comparisons using False Discovery Rate (Q<0.01 and cluster size >15).

Abbreviations: ALFF, amplitude of low-frequency fluctuation; BA, Brodmann area; L, left; MNI, Montreal Neurological Institute; R, right; Cingulum_Post_L, left posterior cingulate cortex; Frontal_Inf_Tri_R, right trigonometric inferior frontal gyrus.

Figure 2 Spontaneous brain activity in the PRL and POL groups. (A) The different ALFF regions between the PRL and POL groups. (B) Significant difference of brain activity in cerebrum. The red regions indicate higher ALFF values, and the green and blue regions imply lower AFLL values.

Notes: (A) The different ALFF regions between the PRL and POL groups. (B) significant difference of brain activity in cerebrum. The red regions indicate higher ALFF values, and the green and blue regions imply lower AFLL values.
Abbreviations: ALFF, amplitude of low-frequency fluctuation; L, left; R, right.

Figure 3 The mean ALFF values between PRL and POL groups.

Abbreviations: ALFF, amplitude of low-frequency fluctuation; L, left; R, right; Cingulum_Post_L, left posterior cingulate cortex; Frontal_Inf_Tri_R, right trigonometric inferior frontal gyrus.

Figure 4 ROC curve analysis of the mean ALFF values for altered brain regions. (A) The area under the ROC curve was 0.980 (P<0.001; 95% CI=0.937–1.000) for SupraMarginal_L, Frontal_Inf_Tri_R 1.000 (P<0.001; 95% CI=1.000–1.000). (B) The area under the ROC curve was 0.987 (P<0.001; 95% CI=0.952–1.000) for Cingulum_Post_L; ParaHippocampal_L 1.000 (P<0.001; 95% CI=1.000–1.000); Vermis_1_2 1.000 (P<0.001; 95% CI=1.000–1.000).

Notes: (A) The area under the ROC curve were 0.980, (p<0.001; 95% CI: 0.937–1.000) for SupraMarginal_L, Frontal_Inf_Tri_R 1.000 (p<0.001; 95% CI: 1.000–1.000). (B) The area under the ROC curve were 0.987 (p<0.001; 95% CI: 0.952–1.000) for Cingulum_Post_L; ParaHippocampal_L 1.000 (p<0.001; 95% CI: 1.000–1.000); Vermis_1_2 1.000 (p<0.001; 95% CI: 1.000–1.000).
Abbreviations: ALFF, amplitude of low-frequency fluctuation; AUC, area under the curve; ROC, receiver operating characteristic; L, left; R, right; Cingulum_Post_L, left posterior cingulate cortex; Frontal_Inf_Tri_R, right trigonometric inferior frontal gyrus.

Figure 5 Correlations between the HADS and ALFF values of left parahippocampal gyrus and left posterior cingulate cortex. The results shown in (A) and (B) both represent a negative correlation with the HADS and ALFF values in left parahippocampal gyrus and left posterior cingulate cortex, respectively.

Notes: The results shown in (A) and (B) both represented negative correlation with the HADS and ALFF values in left parahippocampal gyrus and left posterior cingulate cortex.
Abbreviations: HADS, Hospital Anxiety and Depression Scale; ALFF, amplitude of low-frequency fluctuation.

Figure 6 Significant differences in spontaneous brain activity between the PRL and POL groups. Different brain regions that were observed: 1) SupraMarginal_L; 2) Frontal_Inf_Tri_R; 3) Cingulum_Post_L; 4) ParaHippocampal_L; and 5) Vermis_1_2. The yellow areas present brain areas with increased ALFF values, and the purple areas present brain areas with decreased ALFF values.

Notes: Different brain regions that were observed: (1) SupraMarginal_L; (2) Frontal_Inf_Tri_R; (3) Cingulum_Post_L; (4) ParaHippocampal_L; (5) Vermis_1_2. The yellow areas present brain areas with increased ALFF values. And the purple areas present brain areas with decreased ALFF values.
Abbreviations: ALFF, amplitude of low-frequency fluctuation; L, left; R, right; Cingulum_Post_L, left posterior cingulate cortex; Frontal_Inf_Tri_R, right trigonometric inferior frontal gyrus.

Figure 7 The relationship between changes in internal eye states and vision, brain activity, and emotional state.

Table 3 Brain Regions with Altered ALFF Values and the Potential Impacts

Brain Regions	Experimental Result	Brain Function	Anticipated Results
SupraMarginal_L	Lasik-post<Lasik-pre	Melody processing, short-term memory, visual word recognition, emotional processing	Improved visual function
Frontal_Inf_Tri_R	Lasik-post<Lasik-pre	Language comprehension, inhibition, and attentional control	Hypoactivity of this area
ParaHippocampal_L	Lasik-post>Lasik-pre	Scene perception, spatial representation, emotional processing, episodic memory	Improved visual function, elevated level of visuospatial processing, improved emotional state
Vermis_1_2	Lasik-post>Lasik-pre	Balance and motor control, oculomotor processing	Hyperactivity of this area
Cingulum_Post_L	Lasik-post>Lasik-pre	Cognition, eye movement, visuospatial processing	Improved emotional state

Abbreviations: ALFF, amplitude of low-frequency fluctuation; L, left; R, right; Cingulum_Post_L, left posterior cingulate cortex; Frontal_Inf_Tri_R, right trigonometric inferior frontal gyrus.