Excitatory Repetitive Transcranial Magnetic Stimulation Over Prefrontal Cortex in a Guinea Pig Model Ameliorates Tinnitus

Tinnitus, a phantom auditory perception that can seriously affect quality of life, is generally triggered by cochlear trauma and associated with aberrant activity throughout the pathways, often referred to as hyperactivity. Studies suggest non-auditory structures, such prefrontal cortex (PFC), may be involved in tinnitus generation, affecting sensory gating thalamus, allowing hyperactivity reach lead perception. Indeed, human studies have shown repetitive transcranial magnetic stimulation (rTMS) PFC alleviate tinnitus. The current study investigated whether this therapeutic effect achieved through inhibition thalamic hyperactivity, comparing effects two common clinical rTMS protocols sham treatment, guinea pig model. Animals underwent acoustic once developed were treated either intermittent theta burst (iTBS), 20 Hz rTMS, or (10 days, 10 min/day; weekdays only). Tinnitus was reassessed extracellular recordings spontaneous tonic firing rates thalamus made. To verify PFC, densities neurons positive for calcium-binding proteins, calbindin parvalbumin, using immunohistochemistry. Both significantly reduced compared sham. However, decreased following increased iTBS thalamus. Burst rate different between stimulation, duration only after treatment. Density calbindin, but not parvalbumin neurons, most dorsal region indicating directly affected PFC. Our results support involvement modulation, benefit on treating tinnitus, indicate solely suppression