Prefrontal and Vestibular Cortex Activation During Overground and Treadmill Walking Brian Sylcott 1(&) , Mark Hinderaker 2 , Mason Smith 2 , John Willson 2 , and Chia-Cheng Lin 2 1 Department of Engineering, East Carolina University, Greenville, NC 27834, USA sylcottb15@ecu.edu 2 Department of Physical Therapy, East Carolina University, Greenville, NC 27834, USA {hinderakerm17,smithmas17}@students.ecu.edu, {willsonj,linch14}@ecu.edu Abstract. When walking on a treadmill, people can experience a sensory mismatch resulting from the lack of visual flow. In this study, functional Near‐ Infrared Spectrometry (fNIRS) was used to investigate hemodynamic changes in the brain during overground and treadmill walking. Nine healthy right-handed subjects (25 ± 3 years) were recruited in this study. The test conditions inclu- ded walking overground, on a split‐belt treadmill, and on a standard treadmill. Results showed significantly increased activity in the prefrontal cortex (PFC) and the temporoparietal junction (Vestibular Cortex-VEST) on both treadmills compared with overground walking. Walking on the standard tread- mill significantly increased activation in the PFC and both the left and right VEST compared with the split‐belt treadmill. Our results suggest that walking on the treadmill provokes increased PFC and VEST activation. This finding may explain the fleeting sensation of dizziness after stopping walking on a treadmill. Keywords: Treadmill walking Á Sensory integration Á Functional near-infrared spectroscopy 1 Introduction Treadmill walking is commonly used in rehabilitation to facilitate gait performance [1–4]. Studies have shown the effectiveness of using both standard and split-belt treadmill training to improve gait performance in people with neurological disorders [1, 4]. Joint kinematics are generally similar during treadmill walking compared to the overground walking [5–7]. However, sensory mismatch, due to lack of visual flow, occurs during treadmill walking [8, 9] and people may experience a short spell of dizziness when they resume overground walking following treadmill training. Neuroimaging studies, such as those using functional magnetic resonance imaging (fMRI), have been used to investigate cortical control of gait [10–12]. Cortical regions like the prefrontal cortex, motor cortex, and supplement motor cortex were associated with locomotion [12]. Although fMRI provided a good spatial measurement during © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 H. Ayaz and U. Asgher (Eds.): AHFE 2020, AISC 1201, pp. 225–230, 2021. https://doi.org/10.1007/978-3-030-51041-1_30