Correction: Koush, Y.; Elliott, M.A. and Mathiak, K. Single Voxel Proton Spectroscopy for Neurofeedback at 7 Tesla. Materials 2011, 4, 1548–1563

In the published manuscript "Koush, Y.; Elliott, M.A. and Mathiak, K. Single Voxel Proton Spectroscopy for Neurofeedback at 7 Tesla. Materials 2011, 4, 1548-1563", all estimates of T2* from the single voxel spectroscopy data were overestimated by a factor of 4. This was due to an incorrectly assumed four-fold lower sampling rate. The focus of the manuscript is on the relative changes in T2* with BOLD activation, and not on the absolute values. Therefore, none of the central claims are affected, but the scaling in most of the figures needs to be adjusted. The authors would like to make the following corrections to their published paper. [...].

In the published manuscript "Koush, Y.; Elliott, M.A. and Mathiak, K. Single Voxel Proton Spectroscopy for Neurofeedback at 7 Tesla. Materials 2011, 4, 1548-1563", all estimates of T2* from the single voxel spectroscopy data were overestimated by a factor of 4. This was due to an incorrectly assumed four-fold lower sampling rate. The focus of the manuscript is on the relative changes in T2* with BOLD activation, and not on the absolute values. Therefore, none of the central claims are affected, but the scaling in most of the figures needs to be adjusted. The authors would like to make the following corrections to their published paper.

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1. Figure 1, p. 1551 should be with the correct time and frequency axes: Figure 1. Spectral processing of the single voxel spectroscopic data. (a) Raw (blue) and processed (red) magnitude free induction decay functions (FIDs); (b) Raw (blue) and processed (red) magnitude spectra. Note that graphics and spectra were normalized to their maximum values for comparison purposes and the panels are scaled differently.  shown for a VC fSVPS single voxel ln(FID) data (blue) and its optimal linearization length (red dot; l optim = 19.7 ms, t = 19.12, p < 0.001).

3.
Last paragraph, lines 5-7, p. 1554: For the following sentence the bandwidth should be 2 kHz; not 1 kHz. The acquisition duration = 256 ms should be specified.

4.
Second paragraph, lines 3-5, p. 1556: The sentence with citations [51,52] should be modified to "the absolute T2* values in some subjects differ from those expected"; not "the absolute T2* values differ from those expected".
Although the T2* values show detectable dynamic change in the measured regions due to the BOLD activation, the absolute T2* values in some subjects differ from those expected at 7T for venous blood (T2* < 5 ms), gray matter (T2* ~ 21 ms), and arterial blood (T2* ~ 40 ms) [51,52].
The baseline T2* values averaged across the four subjects were: PMC (T2* offl = 21.1 ± 0.6 ms), PMC NF (T2* nf = 21.8 ± 0.7 ms), and VC (T2* offl = 16.8 ± 0.5 ms).  The maximum t-value ( Figure 6) was specific for selected ROI and time from the beginning of FID acquisition. Thus, with the chosen TE = 20 ms, the maximal t-value attained was around 70 ms after the first excitation pulse in the PMC example.

6.
We apologize for any inconvenience caused to the readers.