Ketamine is an anesthetic drug that works by primarily blocking a certain type of glutamate receptor in the brain, the NMDA receptor. This blockade is responsible for the loss of consciousness when anesthetic doses are given. On the flipside, when it is used at subanesthetic doses the effect is a conscious, yet dissociative experience that is hallmarked by visual stimuli and a dream-like state.
On a systems level, there is an inhibition of what is called the default mode network, or DMN. This network is normally the filter of what is allowed to come to conscious perception and is made of fundamental views or ideologies that an individual ascribes to. For example, our value systems automatically designate some things as more worthwhile than others, and you will navigate the world in such a way that what you deem as important will be obtained. This is a function that can be attributed to the DMN, where basically only items relevant to the pursuit of desired goals are perceived. Finally, ketamine restores lost or depleted synapses in the frontal cortex and hippocampal area that are responsible in part for the contextualization and interpretation of emotional and affective stimuli. These actions culminate in reduced pain, depression, and anxiety.
In addition to ketamine, we use other intravenous compounds to aid in ketamine’s action in reducing negative affect and enhancing neuroplasticity.