[FieldTrip] Fwd: Identify a window of best correlation between ERP and behavioural data

[Harold Cavendish]

Dear FieldTrip users,

I'm looking for the best method to analyse the relationship between ERP and
behavioural data but all I've been able to find so far are methods to
compare ERPs (or more generally time-series).

Consider the following example: 20 participants performed a memory-related
task in which they had to respond based on the difference between the
target stimulus and the probe stimulus. EEG (50 electrodes, about 1000
samples at 200 Hz) and responses were recorded; ERPs were then created
based on epochs in which the responses were correct. Similarly, response
accuracy was averaged over all successful epochs per each subject.

The resulting data are therefore: 20 participants x 50 channels x 1000
samples (ERP) and 20 averages of accuracy (one value per participant).

My objective is to identify which portion of the ERP data best explains (or
predicts) the changes in accuracy. In other words, in which time interval
is the most significant difference between people who do well in the task
and those who don't.

So far I've been doing correlations between ERP at each time point and
overall accuracy, which is unreliable due to multiple comparisons
(correction methods are reportedly too conservative). Nevertheless, certain
channels show quite strong correlations in multiple time intervals.

How would you approach this problem, please?

Many thanks!

Best regards,
Harold
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