{'fraction_non_alphanumeric': 0.019653720168460457, 'fraction_numerical': 0.01169864295741694, 'mean_word_length': 5.269794721407624, '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}}
Perspectives on Neuroscience and Behavior

adult hippocampal neurogenesis supports pattern separation, which can facilitate adaptation to complex environments. Now it has been shown that within a group of genetically identical mice, those that roamed through a larger area of a complex environment had greater hippocampal neurogenesis. Forty inbred female mice were placed in a complex environment at 5 weeks of age and their movement was monitored with a radiofrequency identification passive integrated transponder for 15 weeks and then hippocampal neurogenesis was assessed. Locomotion measured as total number of antenna contacts did not significantly relate to neurogenesis (r = 0.13), but neurogenesis did relate to distance traveled as measured by unique, nonrepetitive antenna contacts (r = 0.34). The variability of cumulative roaming entropy (cRE), a measure of the territorial range covered, increased over the 15 weeks, and during the last 24 days, it more strongly related to neurogenesis (r = 0.46) than locomotion or distance traveled. although there were reliable differences in cRE during the first 24 days, this did not relate significantly to neurogenesis (r = 0.24), indicating that it is the increase in individual differences in cRE that emerged during the observation period that best relate to neurogenesis (Freund and others 2013). as cRE is low if mice travel longer distances to just attend to a few stable spots and cRE is high if mice spend their travel evenly over the entire cage, it is the mastery of the additional cognitive challenge met by the high cRE mice that best relates to neurogenesis. Thus, not only do stable individual differences in exploratory activity emerge over time in genetically identical mice but also the mastery of the cognitive challenge in navigating a complex environment relates best to increased neurogenesis. It should now be possible to independently vary mastery of cognitive challenges and neurogenesis to better understand the temporal relationships and mechanisms involved. an improved understanding of this process can have important applications at the clinical level.