Hypertrophy of neurons in the inferior olive after cerebellar ablations in the cat.

Olivary hypertrophy, a combined retrograde and transneuronal reaction, is found in cells of the inferior olive after cerebellar ablation in the cat. Its chief features are central chromatolysis and hypertrophy of the peripherally located granular endoplasmatic reticulum with accumulation of electron-dense material in its often vacuolarly distended cisterns. Hypertrophy is restricted to subdivisions of the inferior olive included in recurrent cerebello-mesencephalic-olivary circuits.