A 4-year-old blue-fronted Amazon parrot presents with progressive feather destructive behavior, intermittent regurgitation, and a 3-week history of weight loss. Endoscopy reveals thickened proventricular mucosa with dilated ventricular outflow. PCR of a crop biopsy returns positive for Avian Bornavirus (ABV). Which pathological mechanism best explains the neurological component of this disease?

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