Ers in Human Neuroscience www.frontiersin.orgMay Volume ArticleMartins et al.Observing PointLights Depicting Postural Adjustements(Figure), totaling presentations of every stimulus.PLD presentation and EEG recordings had been synchronized by way of a digital trigger signal.Each PLD lasted , ms and was preceded by a fixation cross (interstimulus), presented for any variable time period (amongst , and , ms), to avoid any anticipation or expectancy effects relating to the upcoming animation.The fixation cross was set to assist the subjects position their gaze during the experiment, minimizing eye movements, along with the last ms of this interstimulus period was also applied as a baseline situation.The total duration in the experimental session was about min.After the experimental session, the participants have been asked about their subjective perception from the balanceimbalance level presented in every biological stimulus, similarly to that described previously (see “Preliminary evaluation with the stimuli” section).To compare the scores obtained from QB and UB, we utilised the nonparametric Wilcoxon test, POM1 manufacturer assuming p .postural adjustments, we applied a statistical method comparable to that of Foxe and Simpson and Krakowski et al..Pointbypoint pairedT tests (taking into consideration the entire , ms trial) were calculated amongst EEG time series acquired in every situation (quiet vs.unstable) and in both patterns of pointlight motion made use of PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/21529310 (biological and scrambled stimuli).Differences had been considered considerable only when the following spatialtemporal situation was happy let Tk (t) be the Tscore of electrode k at time t, and let Wk (t) be this worth averaged over consecutive time points ( ms), prior to and right after t (Equation), Wk (t) neig sTk (t s) .and let Wk (t) be the following average over the 3 nearest neighbors of electrode k (equation).WkneigAcquisition of the EEG SignalFor EEG data recording we applied a channel device (Geodesic HidroCel GSN EGI, Electrical Geodesic Inc) built within a soft cap.The signal was amplified by an optic isolated method of high impedance ( M) having a converter AD of bits, along with a nominal achieve of x.The acquisition was performed at a sampling frequency of Hz, and the signal was analogically filtered (Butterworth initially order bandpass filter of .Hz; Geodesic EEG Program , Electrical Geodesic Inc).The impedance from the electrodes was maintained below k for each of the recordings.The electrode positioned on the vertex (Cz) was utilized as a reference in the course of the acquisition.(t) max Wl (t) Wm (t) Wn (t) , l,m,nPreprocessing from the EEG SignalFirstly, the recorded signal was rereferenced from Cz towards the typical reference applying NetStation software program (Electrical Geodesic Inc).Following this process, the information was analyzed offline making use of EEGLab in MatLab’s atmosphere (Math Functions, Version a).The raw information was segmented in events of , ms, discarding the first , ms with the fixation cross and the last , ms from the PLD of each and every event.This segment duration was selected thinking about a window of interest on the 1st , ms immediately after the stimuli onset (see also Hirai et al ; Jokisch et al Krakowski et al Saunier et al).A proportional segment (ms) of fixation cross period was employed to calculate the baseline.Subsequent, a baseline correction was applied utilizing the final ms with the fixation cross signal period.Immediately after that, the signal was digitally filtered within a .Hz band (FIR filter) as well as a notch filter in between and Hz was applied to lower electrical interferences in the power gri.
