Cognitive and kinematic markers of ketamine effects in behaving non-human primates.
European journal of pharmacology – January 15, 2025
Source: PubMed
Summary
Ketamine's effects on brain function reveal fascinating differences in how we move our eyes. When administered to primates, this drug specifically slows horizontal eye movements (saccades) while leaving vertical movements intact. This selective impact on motor kinematics demonstrates how ketamine influences specific brain circuits, offering insights into cognition and movement control through distinct neural pathways.
Abstract
Ketamine is widely used to probe cognitive functions relying on the properties of methyl-D-aspartate receptor (NMDAR) synaptic transmission. Numerous works have proved that cognitive performance and adjustments in the decision or perceptual domains are affected after ketamine injection in general circulation of primates. Here, we take advantage of that in the brain stem; horizontal saccade deceleration is controlled by glycine-NMDAR-gated current, while gamma-aminobutyric acid (GABA) current controls vertical deceleration to demonstrate that despite general circulation level manipulation of NMDAR synaptic transmission, the kinematic of the saccade appeared to be in the motor brainstem generator circuit differentially maintained. The results show that 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 functional distinct markers for estimating cognitive and kinematic NMDAR-gated specificity acting in the pre-frontal cortex while maintaining specificity among the GABA circuit of drugs in general circulation.