<div dir="ltr"><div><div><div>Dear fieldtrip community,<br><br></div>I am running time frequency analysis on my EEG data and when I subtract the response between conditions, the difference condition has much higher amplitude. Could someone suggest what is wrong here? <br><br>Please find the image here:<br><a href="https://www.dropbox.com/s/kh5uzz8000fmh1b/tfr.pdf?dl=0">https://www.dropbox.com/s/kh5uzz8000fmh1b/tfr.pdf?dl=0</a><br><br></div>and here is my script<br><br>cfg                      = [];<br>cfg.trials              = find(s01_ica_clean_artrel_reref.trialinfo==102);<br>cfg.channel          = 'EEG';                    <br>cfg.method           = 'wavelet';                <br>cfg.width              = 7; <br>cfg.output             = 'pow';    <br>cfg.foi                  = 2:2:40;                    <br>cfg.toi                  = -0.4:0.02:0.5;                      <br>s01_cond1           = ft_freqanalysis(cfg, s01_cond1_preprocess);<br></div>% difference<br><div>cfg=[];<br>cfg.parameter='powspctrm';<br>cfg.operation ='x1-x2';<br>s01_difference     =ft_math(cfg, s01_cond1, s01_cond2);<br></div><div>% plot<br></div><div>cfg                     = [];<br>cfg.baseline=[-0.4 -0.1];<br>cfg.zlim=[-0.5 0.5];<br>cfg.xlim=[-0.4 0.5];<br>cfg.baselinetype = 'relchange';<br>cfg.layout              = lay;<br>cfg.interactive         = 'yes';<br>cfg.channel={'FZ'};<br>subplot (1,3,1)<br>ft_singleplotTFR(cfg, s01_cond1);<br>title('deviant');<br>subplot (1,3,2);<br>ft_singleplotTFR(cfg, s01_cond2);<br>title('standard');<br>subplot (1,3,3)<br>ft_singleplotTFR(cfg, s01_difference);<br>title('difference');<br><br></div><div>Thanks,<br></div><div>Arti<br></div></div>