Contingent negative variation and activation of postural preparation before postural perturbation by backward floor translation at different initial standing positions

Postural Responses to Various Frequencies of Vibration of the Triceps Surae and Forefoot Sole during Quiet Standing

“…Backward-lean responses were preceded by an activation of triceps surae (GcM or Sol) and forward-lean responses were preceded by an activation of TA and/or a deactivation of Sol (Fig. 2), as in previous studies (Fujiwara et al, 2011;Kiyota & Fujiwara, 2008;Kurokawa, Fujiwara, & Kiyota, 2013). Activation and deactivation onset was visually determined for each trial, and the amount of time that elapsed from the start of the vibratory stimulus to the onset of EMG change was defined as EMG onset time.…”

“…The inflection point of the CoPap deviation was defined as the onset of the postural response. In all backward-lean response trials, the CoPap shifted slightly forward just before leaning backward, and the start point of the backward or forward deflection was regarded as the onset of the postural response (Fujiwara, Kiyota, & Maeda, 2011). The amount of time that elapsed from the start of the vibratory stimulus to postural response onset was defined as postural response onset time.…”

Anticipatory postural control during arm movements and floor translation

“…Thus, it is difficult to clearly distinguish the readiness potential from the CNV. The peak CNV amplitude corresponds to the peak of anticipatory attention and/or the onset of attentional shift to the output of a motor command [41][42][43] .…”

“…In addition, we have previously investigated the CNV before transient backward floor translations with different initial standing positions 43) . Until the onset of floor translation as the response stimulus, subjects maintained a standing posture in one of four positions represented by the relative distance between CoPap and the heel (Fig.…”

Organização central na geração de ajustes posturais reativos em idosos

“…A maioria dos estudos que verificaram menor automatização do controle postural foi realizada durante postura quieta e em associação com tarefas voluntárias e/ou cognitivas (para uma revisão sobre participação atencional no controle postural veja WOOLLACOTT e SHUMWAY-COOK, 2002). No entanto, um número crescente de estudos recentes têm avaliado a demanda e influência de processos corticais em respostas posturais reativas durante perturbações externas (ADKIN et al, 2008;ADKIN et al, 2006;JACOBS et al, 2008;MIHARA et al, 2008;MOCHIZUKI et al, 2008 DIENER et al, 1991;JACOBS et al, 2008;WHITELAW, 1993;SMITH;HORAK, 2012) e da experiência prévia, com as características das perturbações posturais (BECKLEY et al, 1991;NASHNER, 1989;WHITELAW, 1993;VAN OOTEGHEM et al, 2008 (LIPSITZ et al, 1991;ROBBINS et al, 1989) como também do sistema nervoso MAEDA, 2011;SEIDLER et al, 2010). Tem sido proposto que a diminuição do funcionamento de áreas de processamento de alta ordem envolvidas com o controle postural nos idosos leva a uma compensação por outras áreas possivelmente envolvidas no processamento atencional sensório-motor, diminuindo a automaticidade das respostas posturais (SEIDLER et al, 2010;SIMONEAU, 2001 informações das tentativas repetitivas da perturbação e adotar uma estratégia de controle para manutenção do equilíbrio.…”