loading/browsing data

You can load and browse data in anslab,  using 'viewing' as analysis type. Depending on the data format you have chosen, you are prompted to choose the channels you wish to load ( ACQ, VEE, VPD, EDF  and VIV ) or  the variables you wish to import ( MAT ).  The procedure is described separately for each data format.


BIOPAC acqknowledge (ACQ)  & Vivologic (VIV)
First you specificy how many channels you wish to load:















Then you are prompted for a display sample rate, which loaded data will be resampled to before display. Lower samplerates are faster for drawing, but of course less accurate. For many channels, such as respiration, pulse or eda, a sample rate of 50 Hz is more than sufficient. Other data types, like ecg or emg, need higher temporal resolution (400 , 1000Hz respectively).






As in all other analysis types, when opening a raw data file, anslab checks wether an *.m-file of the same name exists in the folder, where the raw data file is located. If this is the case, the m-file is evaluated as MATLAB-code, in order to read in segmenting information contained in the m-file. If a timing variable is defined in this file, you are prompted to choose the segment to read in, or to read in the entire length of the file,  ignoring  the timing variable. If no segmenting variable can be found or the m-file does not exist, you can choose to load the entire file or the stop data import.
















Then, anslab reads in header information of the file to let you choose each channel to load from a list of channel labels found in the file. For Vivologic files, the channel labels are fixed and comprise only those traces, that are hardcoded in  the viv-file. All other calculated traces are not available to anslab.
















For each channel, you are additionally asked to choose, wether the data type is digital (marker type) or analogue (any physiological data channel). This is important as finding specific values in a signal is much faster for digital channels, than for analog signal. Moreover, a different type of resampling is used for marker type channels, to avoid filter ripple. Generally, if you are loading a psychophysiological data signal, do not set a channel as 'marker type', for any other channel, choose 'yes'.

text files (TXT)
( under construction )

anslab (ans)
This data format is used by anslab to store segmented data as a vector of 'trials', or to store averaged signal (across trials or subjects). If you are loading a 'Cell'-type file, that contains multiple trials, you can only load one file at time and jump from trial to trial using the segment navigation buttons.
If you are loading averaged data segments, you can load a theoretically unlimited number of files and display them together. To do this, load files to a data 'slot', as set with the modifyied file edit box on the anslab menu window:




Files are then plotted together and labelled on a legend according to their file names.

When the 'ANS'-file format is selected, switching to 'Event'-data mode, will allow you to load corresponding statistical ANS-files, that are related to the 'raw' signals. To this end, the 'open data file(s)'-button is changed to 'open stats file(s)' as shown below:

You can load an arbitrary number of stats files. You should make sure however, that f-values and t-values are not mixed, as this will disrupt proper scaling. Stats-files are produced when running   statistical tests (t-tests or ANOVAs) from the 'Calculate'-menu.

matlab data files (MAT)
All standard analysis results in anslab are stored in standard matlab mat-files, in the corrsponding folder for the physiological signal type. You can then reimport these variables to have a look at your analysis results. After choosing a mat-file, anslab reads its entire content, and asks you which variables to load for display:




You can import up to 4 RAW-type variables and 4 EVENT-type variables, that will be accessible in anslab at the chosen data slot. Activate the corresponding data slot, and select the variablename from the adjacent dropdown-box.
For RAW-signals, you additionally have to make sure, the sampling rate is correct, to get correct timing information. EVENT-type variables do not require a sampling rate, but a separate time vector, as they are, by definition, nonuniformly sampled variables. This timing variable is included in mat-files written by anslab and must be selected from the 'timing variable'-dropdownbox.