FAQ  •  Register  •  Login

normalization of marker expression viSNE

Forum rules
Please be as geeky as possible. Reference, reference, reference.
Also, please note that this is a mixed bag of math-gurus and mathematically challenged, so choose your words wisely :-)
<<

juliam

Participant

Posts: 15

Joined: Wed Oct 07, 2020 8:13 am

Post Tue Jun 14, 2022 10:26 pm

normalization of marker expression viSNE

Hi All!

How to do normalization of marker expression on viSNE?
(to have it in range of 0 - 1 for all markers)

Is there such function on Cytobank?

Otherwise sb has code to share to do it in R?


best ,
Julia
<<

BjornZ

Contributor

Posts: 43

Joined: Fri Jul 10, 2015 1:04 am

Post Wed Jun 15, 2022 5:48 am

Re: normalization of marker expression viSNE

Hi Julia,

The version of t-SNE in CellEngine has an option to normalize markers that is enabled by default. See #3, 5th bullet point for documentation: https://docs.cellengine.com/algorithms/ ... algorithms.

-Zach

Disclosure: I work for the company that makes and sells CellEngine.
<<

sgranjeaud

Master

Posts: 106

Joined: Wed Dec 21, 2016 9:22 pm

Location: Marseille, France

Post Wed Jun 15, 2022 9:17 am

Re: normalization of marker expression viSNE

It is quite easy to normalize the data as shown below. The main point is to read the FCS files and write them back once normalized.

IIRC Cytobank is based on the scaling of the channel. Check its documentation or ask support.

CellEngine and OMIQ have straight forward functionality to do it. Don't know about other software.

  Code:
# let's some data in matrix form
mat_exprs = as.matrix(iris[,-5])
# get the range of each column aka dim 2
minmax = apply(mat_exprs, 2, range, na.rm = TRUE)
minmax
diff(minmax)  # the difference between max and min for each column
# remove offset, ie minimal value in each column
mat_norm = sweep(mat_exprs, 2, minmax[1,], "-")
# divide by the difference
mat_norm = sweep(mat_norm, 2, diff(minmax), "/")
# check
apply(mat_norm, 2, range, na.rm = TRUE)
# alternatively, quantile might be useful at targeting a fraction of values
# use the following command as minmax, 5th and 99th percentiles
apply(mat_exprs, 2, quantile, probs = c(0.05, 0.99), na.rm = TRUE)

Return to CyTOF data analysis

Who is online

Users browsing this forum: No registered users and 3 guests