A Cognitive-Motor Dissociation of NMDAR Blockade in Behaving Non-Human Primates

Abstract

Ketamine is widely used to probe cognitive functions relying on the properties of NMDAR synaptic transmission. Numerous works have already proved that cognitive performance and adjustments in the decision or perceptual domains are affected after ketamine injection in the general circulation. Here, we take advantage of that in the brain stem; horizontal saccade deceleration is controlled by glycine NMDA-gated current. In contrast, GABA current controls vertical deceleration to demonstrate that despite general circulation level manipulation of NMDAR synaptic transmission, the skewness of the saccade appeared to be in the motor brainstem generator circuit differentially maintained. The deacceleration of the saccade elicited toward a horizontal target was substantially decreased, while the deacceleration of a vertical saccade remained largely unaffected. These results provide a functional marker for estimating NMDA-gated specificity acting in the pre-frontal cortex while maintaining its specificity among the GABA circuit of drugs in general circulation.