Minor Concerns:
- Table 1 should include a #/% of cells which were “object specific”
- Re Overdispersion analysis (line 460): A linearly scaled Poisson distribution will itself be poisson distributed, not normal, with the approximation being more valid at higher firing rates. The Z value described here will therefore be biased to higher values for lower firing rate neurons. Because of this, it is unclear if the results in lines 90-92 are artificially strong or weak. If thalamic neurons have a higher firing rate than CA3 neurons, they may have an even higher difference in dispersion than reported. A consideration of percentiles rather than standard deviations would likely be revealing.
- Quantification of the object rotation sub-experiment (lines 144-147) should be included in the main manuscript text.
- More details on the properties of theta modulation in dLGN should be presented. What percentage of dLGN neurons had peaks in the theta frequency range in the FFT of their spike train autocorrelations (i.e. how many were significantly theta rhythmic)? What percentage of dLGN neurons were theta phase locked and was there a bias to a particular theta phase? Was theta oscillatory activity in the dLGN modulated by running speed?
- Was a velocity filter used when creating spatial firing rate maps? In a related point, did the authors examine potential differences in mobile vs. immobile activation for dLGN vs. HPC?
- Perhaps we missed it, but what size was the smoothing kernel for 2D ratemaps (in cms)?
- Did the authors examine the spatial distribution of dLGN place fields and, if so, were they uniformly distributed? It would be interesting to know if the fields clustered near objects for example.
- The explanation of the “field index” metric is difficult to understand in the methods and should be clarified if possible.
Other comments:
- The color-coded pass index trajectory plots are not very informative because the dots are all layered on top of each other. Authors could do one or multiple of the following to enhance interpretation: make the dots smaller, make the dots transparent, make the color map sequential rather than qualitative.
- It would be helpful to provide an “n” of the number of place cells in each region in Fig 2g
- Figure 3
- The close up of a single pass in the upper right corner of sub-plots 3b and 3c are confusing. The legend could be revised to clarify what we are looking at. In general, we are a bit unclear as to why the close up of a single pass is necessary. Are we supposed to see rhythmic activity in the spikes? The close up of a single pass is not useful for this because the rat may not be moving at a constant velocity. It may be the case that the spike train above is sufficient.
- BU Neuroscience Preprint JC