The Hack: Precision Interventions
We established that the problem is a rigid, hyperactive Default Mode Network (DMN). To fix it, we need to interrupt the signal. We use two primary levers: Chemistry and Physics.
Level 1: The Chemical Interrupt (Ketamine)
Ketamine is a "dissociative" anesthetic. At sub-anesthetic doses, it creates a temporary disconnect between the Thalamus (the sensory relay) and the Cortex (the processing center). It essentially pulls the plug on the DMN for 45 minutes.
This state of dissociation—often described as "zoning out" or "floating"—is not a side effect; it is the mechanism of action. It gives the rigid network a timeout.
Level 2: The Electrical Interrupt (rTMS)
Repetitive Transcranial Magnetic Stimulation (rTMS) uses magnetic fields to induce electrical currents in specific neurons. We target the Dorsolateral Prefrontal Cortex (DLPFC)—the "CEO" region that is often asleep in depression.
But interrupting the pattern is only half the battle. Once the system is destabilized, it must be reorganized. This is the process of Integration.