# [FieldTrip] Cluster based statistics on channel-channel-freq connectivity

Michael Glassen mglassen at shp.rutgers.edu
Thu Aug 31 23:11:29 CEST 2023

```Just wanted to add some further information, I ran cluster statistics on my connectivity data(32 subjects, 2 timepoints each, conn matrices were 246Channel_246Channel_4Freq(alphaband)). I ran this without a neighbors file, and got 3 clusters with p<.05, with num randomization at 100 for exploratory purposes. These clusters were all similar in that the first channel dimension was the same across the cluster, the second channel dimension were different channels but sequential, and the frequencys were variable. I pasted the results below:

stat.posclusters(1)

ans =

struct with fields:

prob: 0.0099
clusterstat: 136.6784
stddev: 0.0099
cirange: 0.0194

[x y z] = findND(stat.posclusterslabelmat == 1); %findND works the same as matlab builtin find, but works on matrices and returns the indices for each dimension

x =

129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
129
y

y =

26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
28
42
44
46
50
53
54

z

z =

1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2

Best,
Michael Glassen
________________________________
From: fieldtrip <fieldtrip-bounces at science.ru.nl> on behalf of Michael Glassen via fieldtrip <fieldtrip at science.ru.nl>
Sent: Thursday, August 31, 2023 3:16 PM
To: fieldtrip at science.ru.nl <fieldtrip at science.ru.nl>
Cc: Michael Glassen <mglassen at shp.rutgers.edu>
Subject: [FieldTrip] Cluster based statistics on channel-channel-freq connectivity

Hi all,

I wanted to know if it was valid to run cluster based statistics on connectomes created using ft_connectivity analysis on source data generated from ft_virtualchannel. This gives me a connectome with channel_channel_frequency dimensions. If this is valid, I was wondering how neighbors would work. I created a neighbor file for the atlas I’m using that works on power cluster statistics, but I’m unsure how this translates to connectome now that there are channel pairs. I was thinking of editing the connectome to be channelpair_frequency, and creating a neighbor file at the channel pair level. If neither of these neighbor approaches work, would it be valid to run stats without a neighbor file(clustering only based on frequency)? Any input would be appreciated!

Best,
Michael Glassen

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