Measuring calcium activity within individual neurons within the rat thalamus

Detailed methods for imaging calcium activity in single cells within the ventral posteromedial thalamic nucleus of the rat was completed for the first time in these studies. These methods also detail the procedure to image calcium activity in individual GABAergic neurons within the reticular thalamic nucleus using GAD1-Cre rats. This activity was measured in freely behaving rats allowing for recording of activity from GABA neurons during behavioral testing. Key methods for imaging success are: • Calcium activity in the lateral thalamic region is inhibited by isoflurane anesthesia and GCAMP florescent cells are often not observed when mounting the baseplate. • If no cells are observed when mounting the baseplate then place the lens at 300 micrometers or focus on a blood vessel if present. • Depending on the virus, a one microliter infusion could be needed to produce a one millimeter field of GCAMP positive cells for imaging with a lens having a one millimeter diameter.