Fig. 1. Neurotrophins affect LGN neuron size. White bars represent contralateral and black bars ipsilateral values. Size frequency histograms reveal that (A) cortical cytochrome C control and (B) BDNF infusions were not effective. In contrast, (C) cortical NT-4/5 and (D) NGF infusions consistently induced shifts to larger sizes. In the absence of a retrograde tracer all neuronal somata had to be sampled including small-sized cells, which presumably correspond to non-reactive interneurons (representing 20% of LGN neurons) (Sefton and Dreher, 1995). However, the significance levels remained the same when running the tests on only the largest 80% of the neurons. The small insets indicate the median shifts [(ipsilateral median size — contralateral median size)/contralateral median size] in the individual animals analyzed. Positive shifts indicate larger ipsilateral neurons, negative shifts indicates smaller ipsilateral neurons; shifts of up to ±5% were due to biological variation.