Aspectos Éticos

We have shown so far that there are differences in the ongoing oscillatory activity in MI and SI of intact slices. Next, we determined whether these differences seen in the ongoing oscillatory activity in MI and SI depended on the direct connectivity between MI and SI. We did this by placing an incision between the MI and SI border while recording LFPs from MI LIII (n=1), MI LV (n=12) and SI LIV (n=5) (figure 4.1-4.3).

Figure 4. 1. Group-average Morelet-wavelet spectrograms showing effects on oscillatory activity in MI LIII (n=1), seen in a and b (top row), and MI LV (n=12), seen in c and d (bottom row) from severing connections between MI and SI in vitro.

Figure 4. 2. Group-average Morelet-wavelet spectrograms showing effects on oscillatory activity in SI LIV (n=5) before (a, left) and after (b, right) incision between MI and SI in vitro.

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Figure 4. 3 Group- and time-average PSD showing oscillatory profiles of ongoing activity in MI LV (n=12, blue) and SI LIV (n=5, red) before and after severing connections between MI and SI

in vitro. MI LIII is not shown due to low n number (n=1) and large power difference in the

recordings. There is little change in profiles after incision.

4.3.1.1. Frequency and power

The mean peak frequency in MI LIII was 15.50±0 Hz before incision, compared to 11.00±0 Hz after. The mean peak power was 7.24±0 x10-11 V2 before, compared to 19.33±0 x10-11 V2 after. In MI LV the mean peak frequency before was 26.08±6.12 Hz, compared to 25.04±5.81 Hz, after incision. The mean peak power was 7.68±6.50 x10-11 V2, compared to 8.89±8.92 x10-11 V2 after incision. The mean peak frequency in SI LIV before incision was 24.70±5.13 Hz, compared to 22.00±7.50 Hz after. The mean peak power was 6.46±4.37 x10-11 V2, compared to 6.53±6.31 x10-11 V2 (figure 4.4-5). Significance between before and after was tested with Student’s t-test. There were no significant differences. For MI LV and peak frequency: t[11]=0.8576, p=0.4094; for peak power: t[11]=-1.1984,

p=0.2559. For SI LIV and peak frequency: t[4]=0.8089, p=0.4639; for peak power: t[4]=-

0.1418, p=0.8941

Figure 4. 4. Mean peak frequency in MI LIII (n=1, green), MI LV (n=12, blue) and SI LIV (n=5, red) before and after incision between MI and SI in vitro. There were no significant differences. Errorbars are SEM.

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Figure 4. 5. Mean peak power in MI LIII (n=1, green), MI LV (n=12, blue) and SI LIV (n=5, red) before and after incision between MI and SI in vitro. There were no significant differences. SEMs are displayed as error bars.

4.3.1.2 Sensorimotor frequency distribution and variability and MI-SI

connectivity

There were no significant differences in the distribution of network activity in the different locations after incision, as measured by mean FWHM. The mean FWHM in MI LIII before incision was 40.5±0 Hz, compared to 14.50±0 Hz after. In MI LV the mean FWHM before incision was 21.54±9.43 Hz, compared to 20.33±9.71 Hz after. SI LIV the mean FWHM before incision was 18.40±7.73 Hz, compared to 19.4±7.03 (figure 4.6). There were no significant changes; MI LV: t[11]=0.8595, p=0.4053; and SI LIV: t[4]=-0.9428, p=0.3992.

Figure 4. 6. Mean FWHM and frequency distribution in MI LIII (n=1, green), MI LV (n=12, blue) and SI LIV (n=5, red), before and after incision between MI and SI in vitro. There were no significant differeces. SEMs are indicated as error-bars.

We found that the peak frequency variability significantly decreased: 8.84±9.27 to 7.67±8.94 %, t[4]=6.1841, p=0.0035, in SI LIV after incision. The mean percentage of

samples at the peak frequency in MI LIII was 1.31±0 before incision, compared to 5.24±0 % after. In MI LV the mean percentage was 5.84±4.85 before incision, compared to 5.75±9.71 % after (figure 4.7-8); this was non-significant: t[11]=0.1545, p=0.88.

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Figure 4. 7. Mean frequency peak distribution in MI LIII :(n=1, green), MI LV (n=12, blue) and SI LIV (n=5, red), before and after incision between MI and SI in vitro. The mean % of samples found at the peak frequency in SI LIV decreased significantly after incision, p<0.05, marked with *. SEMs are indicated as error-bars.

Figure 4. 8a-d. Group-average peak frequency distribution in SI LIV (n=5), seen in a and b (top row) and normalised power frequency distribution, seen in c and d (bottom row), before and after incision (left vs. right column) between MI and SI in vitro. Physically separating MI and SI in vitro in a sensorimotor slice significantly decreased the variability in SI LIV, p<0.05.

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4.3.1.3. Sensorimotor power state and MI-SI connectivity

The oscillatory power states and associated mean power showed no significant differences after severing connections between MI and SI. In MI LIII the percentage of samples found in the upstate was 38.26 % before and 40.59 % after incision. The mean power in the upstate was 8.93 x10-11 V2 before and 20.03 x10-11 V2 after incision. The mean power in the downstate was 3.72 x10-11 V2 before and 9.62 x10-11 V2 after incision. In MI LV the percentage of samples found in the upstate was 38.62 % and 38.15 % after. The mean power in the upstate was 4.00 x10-11 V2 before and 4.95 x10-11 V2 after incision. The mean power in the downstate was 1.37 x10-11 V2 before and 1.63 x10-11 V2 after incision. There were no significant difference in upstate percentage: t[11]=0.6842, p=0.508;

in upstate power: t[11]=-1.0789, p=0.3037; or in downstate power: t[11]=-1.2383, p=0.2414.

In SI LIV the percentage of samples found in the upstate was 38.59 % and 37.16 % after. The mean power in the upstate was 3.96 x10-11 V2 before and 3.29 x10-11 V2 after incision. The mean power in the downstate was 1.46 x10-11 V2 before and 1.17 x10-11 V2 after incision (figure 4.9-10). There were no significant difference in upstate percentage: t[4]=1.0455, p=0.2548; in upstate power: t[4]=1.0397, p=0.3572; or in downstate power:

t[4]=1.0213, p=0.3648.

Figure 4. 9a-b. Group-averages of the percentages of samples found in the oscillatory upstate in MI LIII (n=1, green), MI LV (n=12, blue) and SI LIV (n=5, red) before and after severing connections between MI and SI in vitro, can be seen in a (left). Figure b shows group-averages of the mean power of the samples found the oscillatory up- and downstate in MI LIII (n=1, greens), MI LV (n=12, blues) and SI LIV (n=5, reds) before (Pre) and after (Post) severing connections between MI and SI in vitro. There were no significant differencesThere were no significant differences.

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