This article provides the key steps for data analysis with Lasa software and data export to Excel. The Excel file containing the physiological variables calculated for several animals studied can be used to draw initial conclusions or to prepare the data for import into advanced statistical software (Graphpad prise, R, Python...).

1.    PREAMBLE

a.    Principle

The aim of this article is to illustrate the procedure to be followed to analyze the data acquired with DECRO.  In the software, analysis and export are performed in the SESSION section of your study.

b.    Learning case (Study example)

A learning case will be used to illustrate the steps of the analysis process in LASA software:

A gavage protocol was carried out in a group of 3 rats with a saline solution in order to quantify the stress effect of handling on cardio-respiratory variables.

c.    Analysis steps introduction

2.    DETECTION

a.   Launch DETECTION

DETECTION enables you to position the various events (R peaks, Vmin and Vmax) on the recorded raw signal using algorithms, in order to automatically obtain the evolution of physiological variables over time. 

Default detection parameters have been carefully defined for each species (DETECT CONFIG LASA VIEW), so simply launch detection with these predefined parameters to visualize and export the evolution of physiological variables over time.

DETECTION parameter values can be adjusted as needed by the user in the DETECT CONFIG window below . The definition of each DETECTION parameter can be found in the USER GUIDE "part 6.3 : Setup the parameters for the automatic detection" available in each DECRO system .

The user guide can be viewed by clicking on the question mark on the system home page.

 

Video 2: Key steps for detecting a recording session with algorithms and obtaining calculated variables

In this video, the DETECTION button is orange because detection has already been performed previously. In the case of the first DETECTION, just after data acquisition/recording, the DETECTION button is GREEN and the MERGE, T0 and ANALYZE buttons are not displayed.

Repeat these steps for each acquisition session, 
Once the detection has been carried out, the "MERGE" session appears. If you click on it, the evolution of the calculated variables over time is display.

b.   Access to post-detection visualization

In our learning case, by clicking on the MERGE session, a new window opens by default with the evolution of heart rate, respiratory rate and activity level (ALL IN ONE view : average over 10 seconds to simplify data display). Markers created (Treatment) during acquisition are positioned at the corresponding time.

3.    LASA ANALYSIS

a. Timeframe of interest

In our learning case, We want to compare a control state before gavage with the state of the animal immediately after the manipulation. We will therefore add colored TIMEFRAMEs on the MERGE in order to find them later in the Excel export file and facilitate analysis.

We will therefore place two TIMEFRAMEs directly on the MERGE as described in the video. We place the "Baseline" TIMEFRAME and the "Handling" TIMEFRAME. Areas of spontaneous animal ACTIVITY were also identified. 

It is necessary to define the different TIMEFRAMEs in the TIMEFRAME button (1) at the top of the SESSION home page just before place them, so that they are available later in the corresponding list (2) in MERGE visualizations.

b. T0

To perform an analysis, we have to define a "T0" to access an analyzed export file.

Simply click on the button available under the MERGE banner.

SOFTWARE : In our learning case, we then choose to use a marker as T0 by clicking on the marker list and selecting the "TREATMENT" marker. Validate by clicking on “SET T0” button.

Define T0 for each session

In this video, the button is “CHANGE T0” because a T0 has already been defined previously. In the case of the first ANALYSIS, the DETECTION button is as follows:  

Indeed, the ANALYZE buttons are not available.

c. Performing calculations (ANALYSE)

To perform an analysis, in addition to defining a "T0", we have to perform calculations (mean, median or sum) on the raw data to access an analyzed export file.

T0 is used to realign the various subjects on the same time base relative to a specific point (different from the start of recording, e.g. Dosing). This tool facilitates the visualization of an effect between subjects in the same experimental group.

Simply click on ANALYZE.

SOFTWARE : In our case, we'll calculate the average over 5 minutes. It is of course possible to define different types of calculation and sampling times for each physiological function. We can also select the type of error you want, between Standard error or SEM.

Once this is done, click on Validate.

Repeat this step for each session. You can launch the analysis for all sessions using the ANALYSE button at the top of the SESSION home page.

4.     EXCEL EXPORT

Once your results have been processed individually, you can bring them all together by exporting them, so that you can carry out your grouped analysis.

a. Tagging before export

To export several subject sessions, we have to placed TAG on each previous analysis.

SOFTWARE : In our case, we click on the menu available in front of the element to be tagged and select the tag “ANALYZED” to assign to it. The tag is displayed in front of the element, just before the menu.

Repeat this step for each session to be exported. (See details in video 6)

It is necessary to define the different TAGs in the TAG button (1) at the top of the SESSION home page just before place them, so that they are available later in the corresponding list (2).

b. Export

Once the different tags have been assigned for each ANALYSIS to be exported, We just have to click on the EXPORT button on the home page of the session part of the study.

Then we choose our ANALYZED tag and click on the EXPORT [1], the Excel format is proposed by default in this case

Finally, we click on GENERATE  and after on DOWNLOAD. The file is downloaded onto the computer …

Video 6 : Key steps for tagging and exporting grouped data

c. Data analysis in excel file

Concerning details of the Excel export content, please refer to the USER GUIDE on the server home page (question mark).

 

SOFTWARE : In our case, to obtain a comparison of cardiorespiratory frequencies between the two states (control vs. post-handling), the following steps were performed:

> Insert a pivot table in a new EXCEL page by using “all” table

> In “Pivot table fields", select the elements of interest and create table (e.g. time frame, cardiac rate and respiratory rate)

> Generate graphics:  in "Insert", "Recommended chart", and in "Insert", click on "Recommended graphics".

By doing the pivot table, you must remind few points : 

-> Use the "Parameters_analyse" category to obtain the value of the parameter in the pivot table

-> The values are displayed summed automatically. Values must be averaged, to do this use the "Value Field Settings dialog box", by left-clicking on the parameter.