Water maze glossary

Every field has its jargon, and the water maze has plenty. Here it is in plain words. If a term you need is missing, tell us.

A B C D E F G H I M O P Q S T V

A

Allocentric and egocentric navigation

Allocentric navigation uses distal cues, such as large cues on the room walls, to find a place.

Analysis grid (open field zones)

The analysis grid divides the arena into cells so you get time, path, entries and latency for each cell. Pick a size that puts each object in its own cell.

Arm entries (multi-arm mazes)

Arm entries count how often the subject entered each arm, using the Detection Area you choose. Arms are listed from the left arm clockwise.

Atlantis (rising) platform

The Atlantis platform sits below the surface and rises automatically when the subject reaches the target. Set the run-screen button to "USB on End" and choose an Auto-end option.

Auto-end

‘Auto-end on platform’ decides whether a trial ends when the subject reaches the platform: ‘Yes’ ends on arrival, ‘Delay in Secs’ after a set stay, and ‘No’ means you end it with ‘END’.

Average and active speed

Average speed is path / trial duration and includes stationary time. Active speed leaves out slow floating periods.

B

Barnes box

The Barnes box shows which maze the screen is running. You don't need to tick it yourself: it is ticked when you open the Barnes maze and unticked when you open the water maze.

Barnes errors and primary path

In the Barnes maze, errors are pokes into wrong holes. Primary path length is the distance to the first approach of the escape hole.

.BOND file

Every VR trial is saved automatically as a JSON .BOND file plus an .hvs file. The .BOND file holds the time-stamped positions and all settings.

C

Calibration

Calibration tells the software the size of your pool or arena and where each target is. All distances use the calibrated pool diameter.

Chaining

Chaining is circling at a fixed distance from the wall, roughly the platform's distance. It is a non-spatial, procedural strategy that can coexist with good latencies.

Circular zones

Circular zones split the pool into rings. Click the explanatory diagram button on the analysis screen to see which letter is A, B or C in your version.

Close encounter (counter)

A close encounter is an entry into a circle (the counter) around a target position, which is less strict than an exact crossing.

CST (custom results) file

A CST file is your chosen set of results, one line per trial and one column per variable, ready to open in Excel.

D

Detection Area

The Detection Area is the % of each arm that counts as an entry: at 100% any entry counts; at 25% only entries to the far quarter.

Direct Path Measures

Direct Path Measures classify whether a trial began with an accurate approach. There are six classes in two groups of three: to Target and to Close Encounter.

Distal cues

Distal cues are large, three-dimensional cues placed far from the pool on room walls or fixed structures, visible to the animals.

E

Elevated plus maze

The elevated plus maze is a widely used test of anxiety-related behaviour: subjects are placed at the junction of the four arms, facing an open arm.

Escape latency

Latency is the time to reach the target. It doesn't show strategy and is affected by speed and start distance, so read it with other measures.

F

Forced swim measures

Forced swim results give % time climbing, diving, swimming and floating, plus total path, duration, average speed and % time moving.

Forced swim tracking band

For forced swim, the tracking area is a band around the water line, sized so the animal's highest point sits in the middle third when swimming or floating.

Freezing

Freezing is staying still for a set time. You decide how many seconds the subject must stay still, and within what distance, for it to count.

'From Poolside' (Direct Path class)

"From Poolside" describes where the direct approach began (near the wall), not continuous wall-following. Sustained wall-following is reported separately as Thigmotaxis.

G

Gallagher proximity

Gallagher proximity measures how close the subject stayed to the target. Global is the average distance (lower = closer; used for probes); Cumulative sums one-second average distances (higher = more search error; used for training).

H

Heading angle

Heading angle shows how directly the subject set off towards the target. Angles near zero mean it headed straight for it.

HVS 6D VR

HVS 6D VR runs virtual experiments such as the VR water maze in a Quest 3 headset; participants can walk on a treadmill or navigate in other ways, such as with the arrow keys.

.hvs file

The .hvs file is the raw data file saved for each trial. Keep every one: your SUM and CST results can be recreated from them.

I

Inactivity (floating)

Inactivity is the percentage of trial time spent below a speed threshold, such as floating in rodents or standing still in VR.

M

Morris water maze

In the Morris water maze, subjects learn to escape from opaque water onto a hidden platform, using cues around the room.

O

Omnidrive treadmill and treadplate

The Omnidrive treadmill or treadplate lets participants walk in VR. Assemble it first, in its final position, then set up the headset around it.

Open field

In the open field the subject explores an arena while the tracker records where it goes. HVS Image gives % time, % path, entries and latency for grid cells, plus speed and freezing.

P

Path efficiency ratio

The path ratio is actual path / shortest direct path. A ratio of 1 is perfectly direct and lower is better.

Path length

Path length is the distance travelled, in metres. It depends on start distance.

Platform crossing

A crossing is a pass over the exact platform location. Whole-trial crossings favour subjects that keep returning over flexible ones that check and move on.

Platform Number (Hole Number)

The ‘Platform Number’ tells each trial which calibrated position is the target. On the Barnes screen it is the ‘Hole Number’.

Pool circling

Pool circling counts complete loops enclosing the pool centre; doubling back does not affect the count.

Probe trial

A probe trial has no platform to find; it shows whether the subject remembers where the platform was. Enter the learned position, tick Probe and turn Auto-end off.

Q

Quadrant entry sequence

The quadrant entry sequence is the order in which the subject visited the quadrants, which helps reveal its strategy.

Quadrants and target quadrant time

The pool is divided into four quadrants, starting at NE and going clockwise. Time in the target quadrant in a probe shows spatial memory when platforms sit at quadrant centres.

S

Subject Size

Subject Size sets how big the tracked object must be. For water maze leave the slider at the left; for dry mazes set it so the tracking box is larger than any droppings but smaller than the animal.

SUM (summary) file

A SUM file holds the analysis of a batch of trials. Highlight the trials, type a name in ‘Name your Summary (SUM) file’ and click ‘Analyze Batch or Series’.

T

TARGET_RADIUS and TARGET_POSITION

In the VR water maze, the trial ends when the participant reaches the target edge defined by TARGET_RADIUS (metres) and TARGET_POSITION.

Thigmotaxis

Thigmotaxis is the tendency of an animal to stay close to the walls of an arena, often called wall-hugging. Early wall-hugging is often adaptation; if it persists it may reflect stress or anxiety.

Time bins (open field and NOR)

Time bins split an open field or NOR trial into periods so you can see how behaviour changes during the trial.

Time slice

A time slice analyses only part of a trial. Slice start 0 and Slice time 30 give the first 30 s; start 30 and time 30 give the next 30 s.

TRACKING_DIAMETER and PLAYER_SCALE

TRACKING_DIAMETER sets the size of the tracked area in a vrScript. For the VR water maze, a diameter of 200 (cm) is recommended so results are comparable with the rodent maze.

Tracking threshold

The threshold sets how the tracker separates the subject from the background. Start at 100 and check the cross follows the subject.

TRIAL_START_POINT (VR positions)

VR positions use six numbers: east, height, north, then three angles. In the water maze, east and north are proportions of pool radius.

TXP (Master Experiment) file

A TXP file is a simple list of trials, easily made in Excel: start point, platform number, subject and descriptor, one row per trial in run order.

V

vrScript file

Each VR experiment is a plain-text .vrScript file, run by pressing its function key after ‘Run HVS 6D VR’. Scripting is text editing, not programming.

Many of these terms have their own explainer on hvsimage.com, starting with what the Morris water maze is.

Spotted a mistake, or know a better source? Tell us and we'll fix it and say so on our corrections page.