This report is a great example of the scientific process. The hypotheses and aims were well laid out, based on prior work. Methods were well-planned in advance also, and deviations from the methods of the prior study are well-justified, and their importance clearly discussed. The aim of the study was to replicate previous novel and exciting findings with respect to possible tinnitus mechanisms, in the form of auditory predictive tendencies, and eliminate hearing loss as the explanation (which has turned out to be the basis of most previously reported ‘tinnitus’ studies that were not rigorously controlled). The study achieves its aims, in an independent group of participants, replicating the original findings. This is a big achievement. The discussion strikes a good balance of recognising the potential importance of the findings, whilst openly acknowledging the remaining uncertainties, and being clear between what its findings demonstrate, and what is still speculation.

I am supportive of publication, but would recommend some minor and moderate revisions first.

Moderate:

Given that matching for hearing was the particular focus and novelty of this study, it would be useful to have more information about hearing matching, for instance:

-          Were the groups only compared in terms of hearing for the average pure tone threshold across all frequencies (for each ear), or were significant differences in individual frequencies sought?

-          Can the authors please provide a figure showing the group mean and standard error of the hearing profiles for each ear?

What does is mean that controls have a negative anticipatory decoding accuracy difference between ordered and random? This is the one part that sits slightly uneasily with me. I do not doubt the findings, but rather I just wonder what it means that people are either ‘un-representing’, or ‘contra-representing’ upcoming stimuli based on learned regularities. As just one possibility of many, could this be because in the random condition it is more likely that the upcoming stimulus was presented 2-3 stimuli back (the probability of the immediately preceding stimuli clearly being exactly 25% in each condition, and therefore equivalent)? I am finding it hard to reconcile something that is less negatively predictive of the upcoming stimulus being an anticipatory prediction. Or, do the authors think that there are two opposing processes here? The authors do highlight this point and make quite a lot of discussion already about it, so perhaps they do not feel in a position to speculate further, but I would encourage them to ensure they have considered all possibilities as fully as they can.

Minor:

In the discussion, I wonder about including the following considerations for future work

-          Attention as another explanation for differences in tinnitus vs. control groups. (Though, MMN studies in tinnitus show diminished responses to sub-tinnitus frequency ranges in people with tinnitus in passive listening paradigms, which is hard to reconcile with increased predictive tendencies).

-          Measuring hyperacusis scores in participants (but, these typically correlate with tinnitus distress, which already has not shown a significant correlation)?

I think that future work using tones around the tinnitus frequency could be highly informative, as it would allow probing of specific differential anticipatory activations between tinnitus and non-tinnitus tones, and might highlight correlates of tinnitus frequency predictions themselves, to complement the existing findings relating to auditory predictive tendencies more generally.

Minor

Abstract:

Clarify whether 80 is number per group or total number of participants (i.e. the latter)

Introduction:
Lines 85-90: Mention some other work (e.g. Adjamian et al. 2012) finding no differences in resting-state delta or gamma between tinnitus and hearing-matched controls.

Results:

Line 650: Please make it clear how hearing loss was controlled for in this statement (e.g. by removing the effect of hearing loss by linear regression)?

Discussion:

Line 687: ‘indication’ should be ‘indicating’

Line 692: A full stop and space is missing

The discussion spends a lot of words repeating the main findings, and could perhaps be streamlined somewhat, without losing content or clarity.

In this stage 2 registered report, participants with tinnitus are shown to display relatively enhanced tone frequency specific pre-activation (i.e. larger differences in decoding accuracy) compared to matched tinnitus-free controls. The authors have carefully complied with their registered Stage 1 study design. Analytical methods have been performed as described in the Stage 1 protocol. Furthermore, the authors have presented their results completely and transparently.

Throughout this report, I have identified some minor issues where information may be lacking or interpretation of the findings might be improved upon. I have outlined these items below. Additionally, I recommend a careful readthrough to identify some very minor grammatical errors (some of which I have also addressed below).

Results 

Figure 4 and the corresponding results section (L502 onwards): Overall, it seems that the primary outcome of this report (the difference in decoding accuracy) shows quite a bit of between-subject variability. Even at the time point with the most pronounced group differences (panel B of Fig. 4), these differences in decoding accuracy show a significant amount of variation, with the distributions for both groups (Tinnitus vs. No Tinnitus) overlapping considerably. Could the authors address this considerable variability and offer some potential explanations for the observed variation? Are there parameters present in the current dataset that are potentially associated with the difference in decoding accuracy, and that could offer some more insight? Or do the authors hypothesize that this between-subject variability is largely driven by factors that were not investigated in the context of this study?

L560 “Together, with the result reported by Partyka et al. (2019), our results strongly support the notion that unspecific distress due to tinnitus is not a good explanation for tinnitus”: This seems to be a typo – could it be that the authors meant that “unspecific distress due to tinnitus is not a good explanation for the identified differences in decoding accuracy”, for example?

L646 and following: Here, tinnitus presence is significantly predicted by the mean difference in decoding accuracy. Could, potentially, the opposite be done, i.e. predict the mean difference in decoding accuracy by group (Tinnitus vs. No Tinnitus)? Would this give us some insight into how much of the between-subject variability in this difference in decoding accuracy (see also my comment above) is explained by the presence of tinnitus, versus the proportion of the variance that would have to be explained by other factors? It might be interesting to have such insights in order to compare the current results to other established differences between tinnitus patients and controls based on evoked MEG or EEG that currently exist in the literature.

Discussion

L686 What would this “neural prediction score” entail specifically? Do the authors propose a concrete numerical score, e.g. the values that are shown in Figure 4B, to be used in future applications? Or is this a broader concept? 

L687 “indication” does not make sense grammatically here, did the authors meant to write “indicating”?

L746 “As they follow the onset the subsequent tone”: I think an ‘of’ may be missing here.