Open Field Thigmotaxis Analysis

Thigmotaxis, the tendency to remain close to walls, is one of the most robust and spontaneous behavioral indicators of anxiety in rodents placed in an open field arena. This protocol specifically quantifies wall-hugging behavior by dividing the arena into three concentric zones: a peripheral zone (within approximately 8 cm of the walls), an intermediate transition zone, and a center zone. The neural circuitry underlying thigmotaxis involves the basolateral amygdala, ventral hippocampus, and medial prefrontal cortex, with anxiogenic stimuli strengthening amygdala-driven avoidance of the unprotected center.

The primary metric is the thigmotaxis ratio, calculated as peripheral zone time divided by total session time. Ratios above 0.80 in the first 5 minutes indicate high anxiety, while ratios below 0.50 suggest reduced anxiety or anxiolytic drug effects. Additional measures include the number of center entries (reflecting willingness to leave the wall), latency to first center entry, mean distance from the nearest wall over time, and the spatial distribution of locomotor activity across zones. The temporal profile of thigmotaxis within a session reveals habituation dynamics, as healthy animals gradually increase center exploration over time.

ConductMaze defines configurable concentric zones based on arena dimensions and a user-specified peripheral margin width, then automatically classifies every tracked position frame into the appropriate zone. The system generates time-in-zone summaries, thigmotaxis ratios per time bin, and spatial heat maps with zone overlays. Distance-from-wall histograms provide a continuous measure of spatial anxiety that is more sensitive than binary zone classification alone.