Running trials

The Run screen is where you set up and record each water maze trial. Trial settings go at the bottom of the screen: 'Max Seconds', 'Single Trial' or 'Series of Trials', Probe, 'Auto-end on platform', Post-trial Timeout, and the trial fields (Trial Name, User Name, Subject, Descriptor, Remark, Start Point and 'Platform Number'). For a series, choose a TXP file with the 'MASTER EXPERIMENT FILES' button. Click 'PREPARE', then 'RUN' as you release the subject. The Barnes maze has its own Run screen with Barnes wording, such as 'Hole Number' and 'Auto-end on escape hole'.

Going deeper

Each water maze trial writes a .hvs raw data file (its name includes trial name, date, time and ordinal number) to C:\HVS Image 2027\Users\[PC username]\Data\Morris Water Maze\HVS. Barnes trials save to the Barnes folders, so the two mazes' data never mix.

If tracking is not yet activated, click RUN. The system check box appears and warns if anything on the computer, including background processes, makes it unsuitable for tracking. Send the red code to HVS via the Support button or contact page, type the code you receive into the activation code box and click OK.

Going deeper

The system check is also a useful diagnostic: background processes can affect tracking.

'Single Trial' means you enter trial details manually for each trial; 'Series of Trials' means details are read automatically from a TXP file. 'Max Seconds' sets the maximum trial duration in seconds.

Going deeper

Series mode reduces entry errors in counterbalanced designs because start points and platform numbers come from a pre-planned file.

'Auto-end on platform' decides whether HVS Image ends a water maze trial automatically when the subject reaches the platform. Choose 'Yes' to end on arrival, 'No' to end it yourself by clicking 'END', or 'Delay in Secs' to end once the subject has stayed on the platform for the number of seconds you specify. With the Atlantis platform these settings also control when the platform rises; choose 'No' to raise it manually by clicking 'END'. For probe trials select 'No'. The Barnes maze Run screen has its own setting, 'Auto-end on escape hole'.

Going deeper

The target area used is the calibrated position for the trial's platform number with the target diameter set in calibration.

Enter the number of seconds for an on-screen countdown at the end of the trial, e.g. to leave the subject on the platform for a set time. The countdown starts after any delay set in 'Auto-end on platform'.

Going deeper

Combined with Delay in Secs, total time on platform = dwell delay + post-trial timeout.

Trial Name is included in the .hvs file name along with date, time and trial number. User Name is your name. Subject is the subject identifier. Descriptor is usually the group. Remark is free text. Start Point is the pool entry point (N, S, E, W, NE, NW, SE or SW). 'Platform Number' is the calibrated platform position number; on the Barnes screen the box is captioned 'Hole Number'.

Going deeper

'Platform Number' refers to the position numbering set during calibration (platform 0 is the first calibrated). For Barnes, enter the target hole position in 'Hole Number'.

A TXP file lists start point, platform (or target hole) number, subject and descriptor, one line per trial in run order. Create it in Excel using the first four columns, or edit EXAMPLE.txp from C:\HVS Image 2027\Users\User\Config\Master Experiment Files\ (import as comma-delimited, delete the instruction rows). Save as [filename].txp, choosing CSV if 'All files' is unavailable.

Going deeper

Saving in Master Experiment Files means it opens automatically when you choose a series file; subfolders and other locations also work.

Enter the series name in Trial Name and your name in User Name. Click 'Series of Trials', then the 'MASTER EXPERIMENT FILES' button (top left) and select your TXP file. The first trial's subject, group, start point and platform position appear at the bottom. If you click 'PREPARE' before choosing a file, the same file window opens for you. If an old subject still shows after 'PREPARE', click 'MASTER EXPERIMENT FILES' to reselect the file.

Going deeper

At the end of a series you can select a new TXP, return to 'Single Trial', move to analysis or exit. Use 'RE-RUN' after ending a trial that needs repeating.

Click 'PREPARE'. For live trials, place the target platform or hole in the correct position, lined up with the on-screen indicator circle. Put the cursor over 'RUN', hold the remote control or mouse in one hand and the subject in the other, and click just as you release the subject.

Going deeper

A long-range wireless presenter or trackball (about 10 m range, steady cursor) is recommended; optical mice are not suitable, and an unreliable single click can start or end trials wrongly.

To track a pre-recorded video, you play the video file into HVS Image instead of the live camera and run the trial as normal. Click the image preview button near the bottom right to select the video, and click 'RUN' when you see the start of the trial on screen (this may be immediately if the video starts at the trial start).

Going deeper

The video must match the camera position used for calibration.

For starting water maze trials away from the computer you need a long-range wireless mouse or presenter, ideally about 10 m range and of a type that keeps the cursor steady (a presenter or track-ball mouse). A wired track-ball on an extension cable also works; optical mice are not suitable. Every mouse must give a reliable single click: a faulty or low-battery mouse can double-click, which can corrupt calibration, fail to start a trial or end it immediately (for example a trial lasting 0.1 s).

Going deeper

Symptoms of an unreliable mouse seen in support cases: trials of about 0.1 s (first click starts, second stops); a .hvs file with no path (immediate stop); no .hvs at all (click not registered); calibration points displaced (double click). Replace or recharge the mouse and repeat. On the water maze Run screen, and on the Barnes maze Run screen, the mouse pointer is locked to 'RUN' after 'PREPARE', and to 'END' after 'RUN', so trials can be controlled from the poolside.