Table 1.
Analysis of the Effect of Attention on Different Frequency Bands for the Different Monkeys and Experimental Conditions
| Experiment | Animal | Variable | Frequency Band |
||
|---|---|---|---|---|---|
| Alpha | Beta | Gamma | |||
| Contrast |
Monkey HU (n = 39) | raw power | p < 0.001 | p < 0.001 | p = 0.010 |
| stimulus power | p = 0.002 | p = 0.004 | p = 0.004 | ||
| STA power | p < 0.001 | ||||
| SFC | p = 0.023 | ||||
| Monkey HO (n = 26) |
raw power | p = 0.167 | p = 0.342 | p = 0.026 | |
| stimulus power | p = 0.048 | p = 0.82 | p = 0.002 | ||
| STA power | p < 0.001 | ||||
| SFC | p = 0.009 | ||||
| Bar length | Monkey BL (n = 12) | raw power | p < 0.001 | p < 0.001 | p = 0.002 |
| stimulus power | p < 0.001 | p < 0.001 | p = 0.005 | ||
| STA power | p = 0.013 | ||||
| SFC | p = 0.011 | ||||
| Monkey HU (n = 135) | raw power | p < 0.001 | p < 0.001 | p < 0.001 | |
| stimulus power | p < 0.001 | p < 0.001 | p < 0.001 | ||
| STA power | p < 0.001 | ||||
| SFC | p = 0.027∗ | ||||
| Monkey HO (n = 46) | raw power | p < 0.001 | p < 0.001 | p = 0.518 | |
| stimulus power | p = 0.003 | p < 0.001 | p = 0.265 | ||
| STA power | p = 0.006 | ||||
| SFC | p = 0.102 | ||||
p values printed in Roman indicate that attention significantly reduced the spectral power and spike field coherence (SFC) in the respective frequency band. p values printed in italics (only monkey HO in the bar length experiment) indicate that attention increased the power in the relevant frequency band. An asterisk (∗) denotes that attention itself did not have a significant effect on the variable of interest, but that there was a significant interaction between attention and the stimulus (bar length in that instance). The table shows that attention generally reduced the gamma LFP power and SFC in the gamma range. An exception are the data from monkey HO in the bar length experiment, although even here the spike triggered average (STA) LFP power in the gamma range was significantly reduced with attention. The differences between this and the other monkeys for the gamma frequency range may be due to different behavioral strategies. Evidence for this is provided in Figure S2. Only 12 experiments are available from monkey BL due to the fact that the animal's implant had to be removed midway through the experiments.