The authors used open-source MRI data sets from the Human Connectome Project (HCP) and examined functional and anatomical connectivity of the nucleus tractus solitaruis (NTS) in the brainstem among a-priori, selected regions of interest (ROIs) of the brain. They described mostly lateralized distributions of NTS connectivity with those regions across the cortical, subcortical, and cerebellar ROIs; as well as predominantly afferent directionality of the NTS signal processing. They went on to discuss clinical implications of the results towards various bodily functions and diseases including chronic regional pain syndrome, which remains speculative but read interesting.

Overall the current manuscript was well written with extensive descriptions of methodology and connectivity results. Despite the limitations of human neuroimaging data in terms of hypothetical arbiturarity of BOLD/diffusion signals, the current efforts might well provide probable human evidence against the past literature based on animal studies regarding the anatomy/functions of the NTS.

I have three concerns:
1) Although the streamline/seed ratio was used as an indicator relevant to anatomical connectivity as well as FA, methods and significance of this index was not explained.

2) Directional connectivity was hard to interpret from only the graphical presentation and legend in Figure 3. More elaborate explanations on how those results meant predominantly afferent signal processing of the NTS.

3) Although the authors mentioned earlier task-based fMRI studies on the NTS functions, they did not even cite any of those papers. They should at least have cited those papers, summarized the findings as well as their strength/limitations, and discussed how the current findings might have added any new knowledge over those past literature.