Brain data, particualrly human brain data have very heterogeneus cell types, so it's important to normalise by cell type. I have used the package BrainInABlender to get a matrix of the proportions of each cell type in each sample

             Sample_1 | Sample 2
Neuron         0.5     |    0.7
Microglia      0.5     |    0.3

The rows are the types of cells, the columns are the samples. I wanted to know what's the best way to add this as a counfounding variable in enrichment browser (or if that's not possible in DESeq2).