The following behaviors and strategies are automatically identified by the HVS Image systems for both rodent water maze and human virtual reality water maze. Both also provide you with detailed analyses and raw data. While others have attempted to identify behavior by analyzing path plot images, that overlooks periods of inactivity and differences in speed at different points in the trial; HVS Image uses position data over time, to give accurate identification of behaviors.
Direct Finding / Direct Path to Target: The subject goes straight to the platform or learned location with minimal deviation.
This typically emerges in later acquisition trials or well-trained subjects, and suggests hippocampus-dependent learning. It indicates:
- Strong spatial memory.
- Accurate allocentric navigation using distal cues.
- Formation of a stable spatial representation of the environment.
Target-Focused Search: The subject spends more than the set threshold amount of time in the immediate area of the platform or target. This identifies subjects persistently searching the immediate area, even when they move very slowly, don’t reach the platform itself, or when the platform is absent in a probe trial.
Target-focused search is often seen after partial learning, in probe trials, or in subjects with mild hippocampal impairment:
- Indicates platform-location memory, but with less specific spatial knowledge or less efficient path planning than indicated by ‘direct path to target’.
- May represent slight uncertainty or imprecise cue integration.
- Has a more precise focus on the immediate surrounding area of the platform than ‘target scanning’ (see below).
Target Scanning: The subject spends time near the platform location, passing the target, returning and passing again, crossing the immediate area around the platform more than the set threshold number of times.
Target scanning may identify intermediate stages of spatial learning. It suggests that:
Strategy refinement may be in progress.
Chaining: The animal swims in a circular path at a fixed distance from the wall, corresponding roughly to the platform’s radial distance. It looks adaptive (the platform can be found reliably, when present) but it’s not a spatial strategy.
The subject remembers the general location of the platform but is not pinpointing it precisely.
The subject may have a partially developed spatial map.
Chaining is common in subjects with hippocampal dysfunction, early in training, or when spatial cues are absent or ambiguous. It suggests:
- A non-spatial, procedural strategy – the strategy allows the platform to be found by covering all points at the learned distance from the poolside, not via spatial memory.
- Egocentric navigation, possibly mediated by the dorsolateral striatum.
Whole Area Scanning: The subject covers all parts of the pool without consistent focus on any specific area (unlike target scanning, which is concentrated near the platform location).
General scanning may be seen during strategy formation and in disoriented or disengaged behavior.
- Suggests the subject is searching randomly or employing a non-specific strategy.
- May reflect uncertainty, early training, or cognitive impairment.
Thigmotaxis: The subject swims along the edge of the pool, hugging the wall.
Excessive thigmotaxis can mask or delay spatial learning and is a key behavioral marker to track, particularly in anxiety or neuromodulation studies:
- Often indicates anxiety, stress, or lack of task engagement.
- Also common in very early training trials before learning begins, as a natural protective behavior on initial exposure.
Inactivity: The subject moves very slowly, or not at all, for much of the trial.
A significant proportion of inactivity or floating may be a sign of disengagement, confusion, sensory or motor impairment, or fatigue.
Take a look at the detailed Morris water maze analyses that compliment the automatic behavior identification.