Widespread Optogenetic Expression in Macaque Cortex Obtained with MR-Guided, Convection Enhanced Delivery (CED) of AAV vector to the Thalamus.

•Introducing an efficient viral delivery technique for optogenetics in NHP.•Convection-enhanced delivery (CED) of virus leads to high levels of expression.•Wide-spread optogenetic expression across cortical areas following thalamic CED.•Expression is limited to specific areas due to thalmo-cortico-thalamic projections.•Reliable light-evoked activity from single cells in cortex following thalamic CED.