A 28-year-old woman presents to the emergency department with severe bilateral lower abdominal pain, fever (38.5°C), and vaginal discharge for 3 days. On examination, she has cervical tenderness and vesicular lesions on the vulva and perianal region. Gram stain of cervical discharge shows no organisms. PCR for HSV-1 and HSV-2 from the vesicular fluid is positive. She reports this is her first episode of genital herpes. Which of the following best explains the neurological complication she is at highest risk for during this acute infection?