{'fraction_non_alphanumeric': 0.02882984737139627, 'fraction_numerical': 0.006783493499152063, 'mean_word_length': 5.082474226804123, '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}}
Increased prefrontal oxygenation prior to and at the onset of overground locomotion in humans.

Our laboratory has reported with near-infrared spectroscopy (NIRS) that prefrontal oxygenated-hemoglobin concentration (Oxy-Hb), measured as index of regional cerebral blood flow, increased prior to and at the onset of arbitrary (i.e. non-cued) ergometer exercise in laboratory environment. In the current study, we hypothesized that naturally-occurring overground locomotion, despite "very light" motor effort as indicated by Borg scale of 8.0 ± 0.3, likewise causes such pre-exercise activation of the prefrontal cortex. Using wireless NIRS, this study examined how early and to what extent prefrontal activity changed prior to the onset of arbitrary walking in 13 subjects. Prefrontal Oxy-Hb increased 2 s prior to the onset of arbitrary walking and the increased Oxy-Hb reached a peak at 5 s from walking onset. The pre-exercise and initial increase in prefrontal Oxy-Hb was absent when overground walking was forced to start by cue. The difference in the Oxy-Hb response between arbitrary and cued start, which was considered to be related to central command, became significant 2 s before walking onset, preceding the difference in the heart rate (HR) response by 8 s and demonstrating a positive relationship with the HR difference in 69% of subjects. Imagery of arbitrary walking was likewise able to increase prefrontal oxygenation to the same extent as actual walking. Thus it is likely that prefrontal oxygenation increases prior to the onset of naturally-occurring walking in daily life, despite "very light" effort. The increased prefrontal oxygenation may contribute at least partly to cardiac adjustment, synchronized with the beginning of motor performance.