Fig. 5

Hypotheses about initial circuit and the effect of speed training. a Hypotheses about initial circuit. In Possible Juvenile State I, the cortical neuron can receive input from an array of LGN cells with a wide variety of position preferences and latencies. In Possible Juvenile State II, the cortical neuron is pre-constrained to receive inputs from cells with particular position and latency values. b Hypothesized adult state. Neurons with particular position and latency preferences converge on the cortical neuron, resulting in direction selectivity. c Impact of providing experience with stimuli moving at different speeds. In Juvenile State I, only LGN neurons with positions and delays that were activated by a particular speed are strengthened, resulting in speed selectivity that matches the experienced speed. d Speed selectivity before and after training under Juvenile State I. e In Juvenile State II, the eventual speed tuning is built-in before the onset of experience, and visual experience with moving gratings merely enhances this pre-constrained tuning. f Speed selectivity before and after training under Juvenile State II. Experiments in ferrets strongly resembled the outcomes in (e) and (f) [39]. Adapted from [39]