Overstimulation and the brain

At the heart of this experience lies the thalamus, a key structure in the diencephalon—the brain's central relay station. Every flash of light, sound, and movement of air passes through the thalamus before reaching consciousness. Under healthy conditions, this hub filters incoming information, allowing the brain to focus on what truly matters.

However, when inflammation, trauma, or toxins disrupt this system, the thalamus becomes overstimulated. The brain loses its filtering ability. Instead of a calm flow of sensations, people experience a "tsunami of stimuli"—a flood of light, sound, and movement that seems uncontrollable.

A key regulator in this system is the cerebellum, also known as the "little brain." Although small, it plays a vital role in maintaining balance—not only physical balance but also sensory balance. The cerebellum helps suppress unnecessary stimuli and supports smooth communication between body and mind. When it is weakened, as can happen after a viral infection (such as COVID-19), neurotoxicity, or brain injury, it can no longer send the necessary inhibitory signals.

One of the brain's natural calming chemicals is GABA (gamma-aminobutyric acid), a neurotransmitter that acts like a brake pedal for overstimulated neurons. When GABA levels drop, the brain loses its ability to slow itself down. Without sufficient GABA, sensory pathways remain open and unfiltered—lights seem blinding, sounds feel painful, and concentration becomes difficult.

Together, these changes—decreased GABA levels, cerebellar dysfunction, and thalamic overstimulation—can make the world unbearably intense. This isn't a matter of imagination or emotional weakness; it's a neurophysiological response. The brain operates in survival mode, struggling to protect itself from an overload of input.