{'fraction_non_alphanumeric': 0.024447031431897557, 'fraction_numerical': 0.027939464493597205, 'mean_word_length': 4.733333333333333, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Effects of age and genotype on acquisition of an active avoidance response in mice.

Two experiments were conducted in which inbred C57BL/6J and DBA/2J mice were trained in an active avoidance jump-up task under distributed practice conditions at a variety of ages comprising a large part of their life-span. DBA/2J mice were found to be basically an escaping strain and exhibited little change in behavior as a function of age. C57BL/6J mice developed consistent avoidance behavior when training was initiated at 31-36 days of age. Avoidance behavior appeared to reach a peak in the 45-day-old group and progressively decreased in 145- and 560-day-old groups. Increased footshock intensity in old DBA/2J mice enhanced escape responding without increasing avoidance responding. Increased footshock intensity in old C57BL/6J mice enhanced avoidance responding.