Fig. 3. Cognitive function assessed by trace fear conditioning. Seven-day-old Sprague-Dawley rat pups were exposed with air or 0.75% isoflurane (Iso) in oxygen with or without saline or dexmedetomidine (Dex) treatment for 6 h. They were allowed to live up to 40 days and then tested for hippocampal-dependent memory and learning function. ( A ) The plot of the mean percentage of freezing time of acquisition against six test trials of trace fear conditioning (day 1). ( B ) The mean of the percentage of freezing time (context results) obtained from trace fear conditioning (day 2). Mean ± SD (n = 6); *= P < 0.05 versus other groups.