Graph Analysis of the Visual Cortical Network during Naturalistic Movie Viewing Reveals Increased Integration and Decreased Segregation Following Mild TBI

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The article examines the impact of mild traumatic brain injury (mTBI) on the observed functionality of the visual cortical network in mTBI subjects during a routine task. The research topic is potentially intriguing, the text is clear, and the main ideas are explained accurately. As a researcher who has spent years investigating the TBI from a different approach, I must express my positive surprise and genuine interest in the research. Listed below are some brief comments:

INTRODUCTION
This section accurately describes the rationale for the research. Perhaps I would suggest including a few statistics on the incidence of TBI around the world so that the reader can understand why the subject is epidemiologically significant. I recommend the read (just introductions) and include the following two references:

·      *   Dewan, M. C., Rattani, A., Gupta, S., Baticulon, R. E., Hung, Y. C., Punchak, M., ... & Park, K. B. (2018). Estimating the global incidence of traumatic brain injury. Journal of neurosurgery, 130(4), 1080-1097.

·   * García-Vilana, S., Sánchez-Molina, D., Velázquez-Ameijide, J., & Llumà, J. (2021). Injury metrics for assessing the risk of acute subdural hematoma in traumatic events. International journal of environmental research and public health, 18(24), 13296.

Authors are welcome to incorporate figures from these sources or any other reference that contextualizes the problem of TBI in terms of population-wide impacts.

MATERIALS AND METHODS
Although the term "functional magnetic resonance imaging" (fMRI) is not defined in the text, its meaning is likely clear to a specialized reader. Nevertheless, the term f should be defined in the abstract the first time it appears for generalist readers.

Sec. 2.3.3 (lines 222-226) In cases where subscripts are misspelled, modify E = (e1, e2,... ek) and V = (v1, v2,..., vn) for expressions in which the subscript is spelled correctly (the statement is $E = (e_1, e_2, \dots, e_k)$ if using the MDPI latex template; if using a Microsoft Word template, the modification is equivalent).

Sec. 2.3.3 (lines 233-258). The same issue as before. But in this case some formulas become challenging to interpret because the improper writing of subindices. Specifically, the equations on line 257 that lack appropriate subscripts require some “deciphering”, which negatively impacts the paper's readability. From my standpoint, lines 233 to 244 could benefit from a more comprehensive explanation regarding the rationale behind the use of these formulas (they are all referenced, but the reasons for its use are not much developed), such as why they were chosen in particular or why alternative measures were not implemented (I have the impression that the authors intend to quickly go through these questions without motivating them in a more convincing way).

RESULTS
The results are clearly exposed and the graphs effectively illustrate the issue; I have no further comments on this section as it is written in a highly pertinent manner.

DISCUSSION
The discussion offers plausible interpretations of the technical results and makes concrete caveats about the limitations that adequately contextualize the scope of the results.

Author Response

INTRODUCTION
This section accurately describes the rationale for the research. Perhaps I would suggest including a few statistics on the incidence of TBI around the world so that the reader can understand why the subject is epidemiologically significant. I recommend the read (just introductions) and include the following two references:

•     *   Dewan, M. C., Rattani, A., Gupta, S., Baticulon, R. E., Hung, Y. C., Punchak, M., ... & Park, K. B. (2018). Estimating the global incidence of traumatic brain injury. Journal of neurosurgery, 130(4), 1080-1097.
•  * García-Vilana, S., Sánchez-Molina, D., Velázquez-Ameijide, J., & Llumà, J. (2021). Injury metrics for assessing the risk of acute subdural hematoma in traumatic events. International journal of environmental research and public health, 18(24), 13296.

Authors are welcome to incorporate figures from these sources or any other reference that contextualizes the problem of TBI in terms of population-wide impacts.

>> We thank the reviewer for this suggestion and have incorporated the statistics into the introductory paragraph.

MATERIALS AND METHODS
Although the term "functional magnetic resonance imaging" (fMRI) is not defined in the text, its meaning is likely clear to a specialized reader. Nevertheless, the term f should be defined in the abstract the first time it appears for generalist readers.

>> We thank the reviewer for this suggestion and have defined the term in it’s first incidence.

Sec. 2.3.3 (lines 222-226) In cases where subscripts are misspelled, modify E = (e1, e2,... ek) and V = (v1, v2,..., vn) for expressions in which the subscript is spelled correctly (the statement is $E = (e_1, e_2, \dots, e_k)$ if using the MDPI latex template; if using a Microsoft Word template, the modification is equivalent).

Sec. 2.3.3 (lines 233-258). The same issue as before. But in this case some formulas become challenging to interpret because the improper writing of subindices. Specifically, the equations on line 257 that lack appropriate subscripts require some “deciphering”, which negatively impacts the paper's readability. From my standpoint, lines 233 to 244 could benefit from a more comprehensive explanation regarding the rationale behind the use of these formulas (they are all referenced, but the reasons for its use are not much developed), such as why they were chosen in particular or why alternative measures were not implemented (I have the impression that the authors intend to quickly go through these questions without motivating them in a more convincing way).

>> We thank the reviewer and have made the changes suggested

RESULTS
The results are clearly exposed and the graphs effectively illustrate the issue; I have no further comments on this section as it is written in a highly pertinent manner.

>> We thank the reviewer for their supportive comment

DISCUSSION
The discussion offers plausible interpretations of the technical results and makes concrete caveats about the limitations that adequately contextualize the scope of the results.

>> We thank the reviewer for their supportive comment

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This study herein used functional magnetic resonance imaging to observe the brain activity of 17 mTBI patients and 54 healthy individuals while watching a simple, non-narrative underwater movie. The methodology of this study demonstrated that mTBI patients exhibited increased overall connectivity and local network specialization, which may have enhanced their ability to integrate information, but did not overload the brain's processing capacity. Compared to healthy controls, patients with mTBI had lower network separation, suggesting that their brains were less functionally compartmentalized. These patterns were consistent across all types of visual cortex subnetworks except for primary visual areas. This study emphasizes the potential of using graph-based neuroimaging techniques and natural stimuli to gain insight into brain network changes in mTBI as well as other disorders that may affect how well the brain integrates.

This manuscript is innovative, with an adequate number of subjects, but it is slightly weaker in reporting experimental content and results. It may be considered for acceptance after further refinement in the following areas.

 

1. The number of figures and tables is too small; other Articles in Vision journals usually have six or more figures and tables. This manuscript provides only three figures. It is recommended to increase the number of figures and tables.

2. Both sections '2.1.1' and '2.1.2' have only one paragraph, and the use of subheadings here gives the impression of a confusing structure. It is suggested to reconsider the use of subheadings in all sections with only one paragraph.

3. It is suggested that part '2.2' should be supplemented with photographs of the experimental process and diagrams of the experimental equipment.

4. Is there a problem of golden subjects in this paper? The following literature provides the neural network that transforms every subject into a golden subject.

B. Sun, Z. Wu, Y. Zhang, H. Zhang, X. Hao, Z. Wei, T. Li*, Golden Subject Is Everyone: A Subject Transfer Neural Network for Motor Imagery-based Brain Computer Interfaces, Neural Networks, 151:111-120, 2022.

5. It is recommended that the '2.3' section be supplemented with a flowchart of the data processing.

6. The font size in Fig. 1 needs to be adjusted consistently and it is not recommended that the font size varies too much in the same figure. In addition, it is recommended that the colors of the points with different meanings in Fig. 1 be appropriately modified to facilitate the reader's understanding. Currently Figure 1 is difficult to visualize the meaning that the author wants to express.

7. Figure 2 has too much white space. And, it is recommended to adjust the font size in the figure to slightly smaller than the font size of the main text. At the same time, it is recommended that the color of Figure 2 be modified appropriately, as the black and grey colors are too monotonous.

8. Why are the significantly different groups in Figure 3 not labeled as in Figure 2? Please revise. Also, it is recommended that the bar graphs for the different groups in Figure 3 be modified to a different color; the current black and grey simply do not show the results that the authors are trying to emphasize.

9. The author's strong writing and analytical skills can be seen from the fourth part of the DISCUSSION. I hope the author will revise the graphs throughout the text with care to make the manuscript more appealing to the readers.

10. The age of the references is too old, and the number of references cited in the last five years is less than 20% of the total number of references. It is recommended to cite more new papers.

11. In the future, is there any connection between movie light modulation of the brain and transcranial light modulation or is there any possibility of integration? It is recommended that the authors read the following literature and discuss it.

T. Li*, P. Wang, L. Qiu, X. Fang, and Y. Shang, Optimize illumination parameter of low-level laser therapy for hemorrhagic stroke by Monte Carlo simulation on Visible Human Dataset, IEEE Photonics J., 10(3):6100409,2018.

Author Response

 

1. The number of figures and tables is too small; other Articles in Vision journals usually have six or more figures and tables. This manuscript provides only three figures. It is recommended to increase the number of figures and tables.

>> We thank the reviewer for this suggestion. However, we strived for succinctness and sought to only provide graphical representation of material not stated in the text, to avoid replication.

2. Both sections '2.1.1' and '2.1.2' have only one paragraph, and the use of subheadings here gives the impression of a confusing structure. It is suggested to reconsider the use of subheadings in all sections with only one paragraph.

>> We are grateful for this comment and have merged the two sections under one heading.

3. It is suggested that part '2.2' should be supplemented with photographs of the experimental process and diagrams of the experimental equipment.

>> We thank the reviewer for this suggestion and have created the figure in the revised manuscript

4. Is there a problem of golden subjects in this paper? The following literature provides the neural network that transforms every subject into a golden subject.
5. Sun, Z. Wu, Y. Zhang, H. Zhang, X. Hao, Z. Wei, T. Li*, Golden Subject Is Everyone: A Subject Transfer Neural Network for Motor Imagery-based Brain Computer Interfaces, Neural Networks, 151:111-120, 2022.

>> This is a very interesting reference and idea, and we thank the reviewer for suggesting it. We will likely use this methodology in our forthcoming studies on fMRI-feedback, which requires training of classifiers and for which feedback-naïve subjects can have great difficulty.

5. It is recommended that the '2.3' section be supplemented with a flowchart of the data processing.

>> We thank the reviewer for this suggestion and have created the flowchart in the revised manuscript

6. The font size in Fig. 1 needs to be adjusted consistently and it is not recommended that the font size varies too much in the same figure. In addition, it is recommended that the colors of the points with different meanings in Fig. 1 be appropriately modified to facilitate the reader's understanding. Currently Figure 1 is difficult to visualize the meaning that the author wants to express.

>> We thank the reviewer for this suggestion and have adjusted the figure accordingly.

7. Figure 2 has too much white space. And, it is recommended to adjust the font size in the figure to slightly smaller than the font size of the main text. At the same time, it is recommended that the color of Figure 2 be modified appropriately, as the black and grey colors are too monotonous.

>> We thank the reviewer for this suggestion and have adjusted the figure accordingly.

8. Why are the significantly different groups in Figure 3 not labeled as in Figure 2? Please revise. Also, it is recommended that the bar graphs for the different groups in Figure 3 be modified to a different color; the current black and grey simply do not show the results that the authors are trying to emphasize.

>> Thank you for the comment. The figure has been updated and improved.

9. The author's strong writing and analytical skills can be seen from the fourth part of the DISCUSSION. I hope the author will revise the graphs throughout the text with care to make the manuscript more appealing to the readers.

>> Thank you for the suggestion!

10. The age of the references is too old, and the number of references cited in the last five years is less than 20% of the total number of references. It is recommended to cite more new papers.

>> We thank the reviewer for this suggestion and have added several more recent papers.

11. In the future, is there any connection between movie light modulation of the brain and transcranial light modulation or is there any possibility of integration? It is recommended that the authors read the following literature and discuss it.
12. Li*, P. Wang, L. Qiu, X. Fang, and Y. Shang, Optimize illumination parameter of low-level laser therapy for hemorrhagic stroke by Monte Carlo simulation on Visible Human Dataset, IEEE Photonics J., 10(3):6100409,2018.

>> we thank the reviewer for the suggestion, as this cited work is incredibly interesting and exciting, but perhaps more relevant to a surgical intervention study than ours which is about neuroimaging.

 

Author Response File: Author Response.pdf