Peer Review History
| Original SubmissionJune 27, 2025 |
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PONE-D-25-33484Study of changes in brain dynamics during sleep cycles in dogs under effect of trazodonePLOS ONE Dear Dr. Mateos, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Sep 26 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript:
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Or, if the data are not a core part of the research being presented in your study, we ask that you remove the phrase that refers to these data. 4. If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise. Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Partly ********** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes ********** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes ********** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes ********** 5. Review Comments to the Author Reviewer #1: This study investigates the neurophysiological effects of trazodone on sleep-related brain dynamics in healthy dogs, leveraging EEG analysis to characterize changes across wakefulness, drowsiness, NREM, and REM sleep stages. The authors used hypnogram analysis to assess sleep architecture and applied both linear (PSD) and non-linear (PE, LZC) metrics to evaluate EEG complexity, alongside connectivity measures such as Phase Lag Index and coherence. Results show trazodone modifies sleep cycles, reduces low-frequency power, increases higher-frequency activity during Drowsiness and NREM, and alters brain signal complexity and connectivity across sleep stages. These findings offer new insight into the short-term neural impact of trazodone in canine models. The study explores interesting and relevant topic. However, it raises several important questions and has both major and minor limitations. The following comments are listed in the order they arose during the review, meaning that minor and major points are interspersed throughout. - How much dog size (e.g. breed) affect to usual health and physiological function altogether and therefore to your results also? As I have understood smaller breeds live longer than bigger ones, e.g. Bernese mountain dog (~8 years) vs. Tibetan Spaniel (~14 years), as in your dataset there are also bigger (e.g. labrador) and smaller (maltese) breeds? - How much different breeds skull size and structure affect to your analyses? With different sizes the power are also different? Especially since you use Wilcoxon test. How appropriate it would be to use paired methods where you actually compare same subject different statuses? I.e. how independent the samples are if the dogs are the same? Would paired analysis work? What are the shortcomings for using paired analysis in this study? Nevertheless, limitations section should be modified accordingly depending on which statistical analyses you use. Additionally, in your dataset is there any chance of multiple comparison problem that would affect the analyses? - I would presume that different dogs have different need for daytime naps. How this different need would affect to different sleep stages and results during daytime recording between 12.30PM and 1.30PM? - In your “Signal preprocessing” chapter, you say “Artifact-free, stable epochs were then carefully selected for quantitative EEG analysis.” -> how many epochs were selected for each subject? I would be interested number of epoch or % share of whole recording that was analyzable. If there were some discrepancies between subject, e.g. for some had 90% good data while other had only 20%, especially if same subject % shares were totally different between two nights -> how you take these differences into account? Would not this affect your percentages of different sleep stages, if e.g. for some subject the artefact time happens to be e.g. during REM sleep? (It seems that you explain this later in line 150 forward, but still these numbers of epoch etc would be interesting to see?) - Sorry, I do not have access to your ref 21, and therefore I can’t check on this myself, however it would be interesting to see (at least as in your answer not necessarily in manuscript) what are the 3 second epochs criteria for REM sleep and/or NREM also? If this would be possible? You say the usual guidelines in line 122-128, however this 3 second epochs puzzles me as I have got used to human AASM criteria with 30s epochs? - Ýou probably mean Fig 2A in line 141 rather than Fig 1A? - You also say in line 141 forward that “the hypnograms of animals with and without trazodone exhibit clear visual differences, indicating that trazodone affects sleep cycles, resulting in reduced variability.” Yes the difference is clear, but I would not have raised that view up as for me it seems that during trazodone they actually sleep (NREM+REM) much less than in normal conditions (and yes the structure of sleep is totally different, but that is another topic)? Additionally, this is methods section so it seems odd to process results in this section, although it functions as bridge for LZC analysis. Maybe in that sense it is okay? - Another point of those hypnograms, as I am not that familiar with studies done with dogs, is it normal to illustrate hypnogram from top to down as REM ->NREM -> drow ->wake? As usually hypnograms are illustrated top to down as wake -> REM -> N1 -> N2 -> N3? For me it seems odd to have wake section the lowest? - In line 150 you actually explain my previous point regarding variability of number of epochs. However, you say that you five epochs? Meaning that you actually analyzed only 15 seconds? Each epoch had 1200 timepoints as usual for 400Hz resolution, however your bandpass was between 1-70Hz, so majority of this 400Hz goes unanalyzed. Is 15 seconds actually enough for these analyses? It seems quite low number? Additionally, if “epochs were chosen randomly to ensure fairness” how especially the connectivity analyses actually work with 3 second epochs? - In line 156 there is extra space before “Power” same thing with in line 212 before “Phase” - In line 220 you use the most physiologically representative EEG bands, is this under normal conditions or also with trazodone? How much there are variability between subjects? Is it possible that something interesting is left out with the chosen bands in individual subjects? - In Fig 2B and line 261 onwards, how these deleted and not analyzed epochs affect these total time calculations? - I would be interested to see similar charts for total analyzed time contr vs trazodone and time wake vs sleep between two conditions. Not necessarily in actual manuscript but at least in your answers? - Line 275 typo, “Thi” miss the S - I am still thinking that your interpretation in line 277-278 is little off. Of course this might be the case, however, in my eyes the shown data does not fully support this. The thing that got me puzzled is mainly that trazodone should be “sleep medication” so why the dogs keep awake-drowsiness for longer time? And this affects naturally the whole structure of sleep in a timeframe of 120min? - In line 280 and Fig 2E you present transition probability between epochs? So, in this you use all epochs not only the 5 that you randomly selected before? With the used and analyzed data there seems to be some discrepancies in my eyes. Is it possible to explain these better? My confusion continues in PSD chapter as in lines 307-308 you say that number of samples in trazadone group is 60% less (which, as I have said before, would be interesting to see as in table or chart), but how this is possible if you have selected 5 epochs in each state for every subject as stated in the beginning of EEG analysis chapter? I am sorry if I am not able comprehend this fully, but for me this seems odd? - Fig.3 legend between lines 308 and 308 there is a typos? “anlysis” and “de” - Statement in line 329 comes with surprise, I think these statements and results should be explained first? How this affects the whole analyses as different dogs are included in analyses and therefore size, skull etc affect the results? - Extra space in line 361 (see method ) - Typo? In Fig.5 legend “---analysis for all PARE of electrodes”? Pair? - Lines 404-409 same text two times, i.e. “The administration of trazodone over the time has been demonstrated to enhance the quality of sleep in humans and rats through a reduction in the proportion of time spent in a Wakefulness state and an increase REM, NREM sleep [54–56]. The administration of trazodone over the time has been demonstrated to enhance the quality of sleep in humans and rats through a reduction in the proportion of time spent in a Wakefulness state and an increase REM, NREM sleep [54–56].” ********** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No ********** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". 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| Revision 1 |
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Study of changes in brain dynamics during sleep cycles in dogs under effect of trazodone PONE-D-25-33484R1 Dear Dr. Mateos, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Assoc. Prof. Phakkharawat Sittiprapaporn, Ph.D. Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation. Reviewer #1: All comments have been addressed ********** 2. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes ********** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes ********** 4. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes ********** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes ********** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: The authors have addressed all of my comments and provided thorough explanations. While I differ slightly from some of them on a few speculative points, I cannot find any actual fault in their responses. Consequently, I consider the authors’ interpretations and explanations in the manuscript to be sound. ********** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No ********** |
| Formally Accepted |
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PONE-D-25-33484R1 PLOS ONE Dear Dr. Mateos, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset You will receive further instructions from the production team, including instructions on how to review your proof when it is ready. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few days to review your paper and let you know the next and final steps. Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. You will receive an invoice from PLOS for your publication fee after your manuscript has reached the completed accept phase. If you receive an email requesting payment before acceptance or for any other service, this may be a phishing scheme. Learn how to identify phishing emails and protect your accounts at https://explore.plos.org/phishing. If we can help with anything else, please email us at customercare@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Assoc. Prof. Dr. Phakkharawat Sittiprapaporn Academic Editor PLOS ONE |
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