My prolonged collaboration with Ray Guillery.

My active collaboration with Ray Guillery started in 1968, when he was a Full Professor at the University of Wisconsin and I was a graduate student at the University of Pennsylvania. The collaboration lasted almost 50 years with virtually no breaks. Among the ideas we proposed are that glutamatergic pathways in thalamus and cortex can be classified into drivers and modulators; that many thalamic nuclei could be classified as higher order, meaning that they receive driving input from layer 5 of cortex and participate in cortico-thalamocortical circuits; and that much of the information relayed by thalamus serves as an efference copy for motor commands initiated by cortex.