216 Journals of Gerontology: Biological Sciences cite as: J Gerontol A Biol Sci Med Sci, 2021, Vol. 76, No. 2, 216–223 doi:10.1093/gerona/glaa125 Advance Access publication May 19, 2020 © The Author(s) 2020. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com. Original Article Frontal Hemodynamic Response During Step Initiation Under Cognitive Confict in Older and Young Healthy People Daniel Boari Coelho, PhD, 1, * , Paulo Rodrigo Bazán, BSc, 2,3, Guilherme Augusto Zimeo Morais, BSc, 2 Joana Bisol Balardin, PhD, 2 Alana Xavier Batista, MSc, 3 Claudia Eunice Neves de Oliveira, MSc, 1 Emanuele Los Angeles, BSc, 1 Claudionor Bernardo, BSc, 1 João Ricardo Sato, PhD, 4 and Andrea C. de Lima-Pardini, PhD 5 1 Biomedical Engineering, Federal University of ABC, São Bernardo do Campo, São Paulo, Brazil. 2 Big Data Analytics - Hospital Israelita Albert Einstein, São Paulo, Brazil. 3 Department of Radiology, Faculty of Medicine, University of Sao Paulo, São Paulo, Brazil. 4 Center of Mathematics, Computing, and Cognition, Universidade Federal do ABC, São Bernardo do Campo, São Paulo, Brazil. 5 Laboratory of Integrative Motor Behaviour, Centre for Neuroscience Studies, Queen’s University, Kingston, Ontario, Canada. *Address correspondence to: Daniel Boari Coelho, PhD, Centre for Engineering, Modeling and Applied Social Sciences (CECS), Federal University of ABC (UFABC), Alameda da Universidade, s/no, Bairro Anchieta, São Bernardo do Campo, SP 09606-045, Brazil. E-mail: daniel.boari@ufabc.edu.br Received: February 24, 2020; Editorial Decision Date: May 11, 2020 Decision Editor: David Le Couteur, MBBS, FRACP, PhD Abstract Gait initiation is a daily challenge even for healthy individuals as it requires the timely coupling between the automatic anticipatory postural adjustment (APA) and the voluntary step according to the context. Modulation of this motor event has been thought to involve higher level brain control, including cognitive inhibitory circuitries. Despite the known participation of the supplementary motor area (SMA) in the modulation of some parameters of APA, the participation of areas controlling inhibition during gait initiation still needs to be investigated. In this study, the hemodynamic responses of the SMA and dorsolateral prefrontal cortex (DLPFC) were assessed using functional near-infrared spectroscopy (fNIRS) during a gait initiation task under cognitive confict to select the foot to step (congruent [CON] and incongruent [INC] conditions). The older group (OG) showed worse inhibitory control than the young group (YG) along with more impairments in APA parameters. OG also had a lower amplitude of hemodynamic responses in both areas than YG in the INC. The INC increased the correlation between SMA and DLPFC only in the YG. Aging seems to impair the interaction between the hemodynamic responses of SMA and DLPFC, which infuences APA performance in gait initiation under cognitive confict. Keywords: fNIRS, Anticipatory postural adjustment, Biomechanics, Motor control, Functional brain imaging Anticipatory postural adjustments (APAs) are essential to counter- balance predictable forces exerted on the body, being time locked and spatially adjusted to the demands of the upcoming task. Specifcally, APA during gait initiation involves the shifting of the body mass back and toward the moving leg, then toward the sup- port leg before the step is taken (1). Although being part of distinct neural pathways (2), the APA and its associated voluntary move- ment are frequently perfectly coupled during stepping. If the body weight is shifted to an unsuitable direction, this must be corrected before the step is released (3). Some evidences on the APA control during gait initiation have pointed out the involvement of high level of cognitive processing, mainly comprising the supplementary motor area (SMA) (4–6). SMA during gait initiation may participate in the process of inhibiting prepotent neural commands that could result in the release of a step inappropriate to the context (4,7,8). Therefore, the frst phase of the APA, when the body weight is being shifted toward the moving leg, should be timely inhibited and reversed to the support leg, so the voluntary step could be released as required. Interestingly, healthy young and older people show negative correl- ation between cognitive tests to assess inhibitory control and errors of APA during conficting gait initiation tasks (3), highlighting the participation of cognitive function in the control of APA. Downloaded from https://academic.oup.com/biomedgerontology/article/76/2/216/5840538 by guest on 18 April 2023