Quadrant entries in Morris water maze analysis

While the percent of time or path in each quadrant are valuable in assessing spatial preference and memory, quadrant entries provide unique insights into strategy use, perseveration, repetition, and exploration structure.

HVS Image systems provide both the number of times each quadrant is entered, and the sequence of quadrant visits. These are especially valuable in models of rigidity, psychiatric conditions, aging, and procedural strategy use.

Number of quadrant entries
The number entries to each quadrant provides different and complementary information to the amount of time or path in each quadrant. Time or path tells you where the subject spent most of the time or path (typically interpreted as an index of spatial preference or memory) and is cumulative, so does not distinguish between a single long visit vs multiple short visits. Quadrant entries give you insights into how actively or broadly the subject explored – whether it moved between quadrants frequently or kept a narrow spatial focus.

The numbers of entries to each quadrant may be of interest in, for example:

  • Hyperactivity models (e.g., ADHD, stimulant exposure): high number of entries into all quadrants expected.
  • Apathy or freezing (e.g., chronic stress, sedation): low number of entries expected.
  • Perseveration (e.g., OCD, autism, striatal overtraining): repeated entries may be made to the same 1-2 quadrants.
  • Spatially trained subjects: fewer entries overall, concentrated in the target quadrant.

Sequence of entries
The order in which quadrants are visited can also uncover search strategies, procedural behavior, or spatial intent that aren’t captured by cumulative measures such as the time or path in each quadrant or the Gallagher measures. For example:

  • Sequential quadrant visits may suggest procedural strategies like chaining (e.g. scanning in a circular path at fixed distance).
  • Repetitive quadrant switches may indicate perseverative loops, restricted search fields or repetitive or compulsive behavior.
  • Direct early entry into the target quadrant may suggest initial spatial memory, even if the subject then searches elsewhere.
  • Randomized entry order may suggest lack of strategy or disengagement.