Figure 2.

Time course of nociceptive withdrawal reflex (NWR) postnatal adaptation. Graph shows percentage of error rate of heat-nociceptive withdrawal reflex in three litters. The distal tail was stimulated daily, twice bilaterally during P1-P28 in two litters (•n = 12; ^*n = 8), and six times on each side in a third litter (○n = 13). Mean ± SEM are shown. The inset shows a schematic of the experimental set-up. Tail movements in the horizontal plane, elicited by CO₂ laser, were classified as erroneous (directed toward stimulation) or correct (directed away from stimulation).