E N D
1. Spikes analysis in EEG and MEG jfernan@det.ua.pt
IEETA/DETI@UA
2. Spikes in EEG and MEG Question
Are EEG spikes equal to those found in MEG?
Methods
Measure the “shapes”
Normalized with background activity
Selected Spikes
Occurring in both EEG and MEG
Occurring at same time (+/- 35 ms)
Compare measures
3. Spike model: Measures Duration (Dur)
PP1/PP2
Sharpness (C)
4. They are statistically different
5. EEG and MEG spikes Don’t trust the looks
They are different
MEG spike is
“smaller”
Shorter (take less time)
6. MEG spike is shorter than EEG Don’t trust the looks
They are different
MEG spike is
“smaller” (shrink)
Shorter (take less time)
7. MEG spike is “smaller” Don’t trust the looks
They are different
MEG spike is
“smaller” (shrink)
Shorter (take less time)
8. MEG spike is “smaller” Don’t trust the looks
They are different
MEG spike is
“smaller” (shrink)
Shorter (take less time)
9. MEG spike is shorter Don’t trust the looks
They are different
MEG spike is
“smaller” (shrink)
Shorter (take less time)
10. MEG spike is shorter Don’t trust the looks
They are different
MEG spike is
“smaller” (shrink)
Shorter (take less time)
11. MEG spike is shorter Don’t trust the looks
They are different
MEG spike is
“smaller” (shrink)
Shorter (take less time)
12. MEG spike is shorter Don’t trust the looks
They are different
MEG spike is
“smaller” (shrink)
Shorter (take less time)
13. EEG and MEG spikes Don’t trust the looks
They are different
MEG spike is
“smaller” (shrink)
Shorter (take less time)
14. Conclusions Results imply that the processes of visual inspection of MEG spikes and automatic spike detector algorithms should be modified in relation to those used in EEG.