Figure 4.

FM direction selectivity is poor in pup cortex. A, This neuron was selective for the downward direction of FM sweep. Upward sweeps with the same BW elicited weak responses at all FM rates tested. B, This neuron was not selective for FM sweep direction. It responded well to both directions at certain rates. C, The percentage of direction-selective neurons was <35% up to 8 weeks after birth. Direction selectivity reached adult-like percentages in pups >12 weeks old. A, Adult. D, DSI in pups younger than 8 weeks was on average <0.3. In the >12-week-old group, DSI values were intermediate between the young pups and the adults.