Bilateral reorganisation of mossy fibres in the rat hippocampus after a unilateral intracerebroventricular kainic acid injection.

One month after a unilateral intracerebroventricular injection of the neurotoxin kainic acid (KA) a prominent band of zinc-containing Timm's-stained terminals is present in the inner molecular layer of the ipsilateral dentate gyrus. At 3 months, mossy fibre reorganisation is also seen in the contralateral inner molecular layer of the dentate gyrus and in the infrapyramidal band in the contralateral CA3. The relationship of this reactive plasticity to the CA3 lesion is discussed.