Knowledge Base

Problem

When enabling fine/detailed behavior recognition in EthoVision XT, the user receives a 'resolution too small for Behavior Recognition' error. The animal body is not detected with sufficient pixel size to allow the behavior recognition module to function.

Details

Affects EthoVision XT versions with the Automatic Behavior Recognition module. Occurs when the camera resolution, zoom level, or arena size results in the animal body occupying fewer than 55 pixels in length within the detection frame. Users may also ask about the minimum time bin size and how to correlate zone entry/exit frequency data with fiber optic or calcium imaging recordings.

Solution

1. Open Detection Settings and check the detected body length in pixels. The animal body must be at least 55 pixels long for behavior recognition to function.
2. To increase pixel size: (a) physically zoom the camera in on the arena to reduce the field of view, (b) increase the camera resolution in Pylon Viewer / acquisition settings, or (c) reduce the arena area so the animal occupies a larger proportion of the frame.
3. For time bins: values smaller than 30 seconds can be entered manually (down to millisecond level), though very fine bins will generate large datasets.
4. To correlate zone data with fiber photometry: export the 'Frequency' parameter from the analysis zone settings. This provides entry/exit timestamps that can be matched against fiber optic recording markers using timestamps.