path = File.openDialog("Select a file");
open(path);
setBatchMode(true);
dir = File.getParent(path);
name = File.getName(path);
folderName = split(name, ".");
folderPath = dir + "/" + folderName[0];
File.makeDirectory(folderPath);
for (i=1; i<=nSlices; i++) {
    saveAs("Text Image", folderPath + "/Slice_" + pad(i) + ".txt");
    run("Next Slice [>]");
    }

function pad(n) {
    n = toString(n);
    while (lengthOf(n)<5)
         n = "0"+n;
    return n;
}