How can I read half of a 3-D matrix variable from a netCDF file?

I have a variable from a netCDF file that is 1024x1024x4284. Using ncread, it is too large to import at once, so I want to split it in half and import the two halves separately. How can I do this?

I have tried using ncread:

ncread("filename",'varID',[1,1,1],[1024,1024,1]);

I believe this gives me the first layer, but how can I modify this so I can get a 3-D matrix of 1024x1024x2142?

Thanks!