Knowledge Base

Analyze Data - Dependent Variables

Standard Available Output Variables

• Velocity – Distance traveled by the body point per unit of time.
• Distance Moved – The distance traveled by a body point from the previous sample to the current one.
• In Zone – A discrete variable with two possible states, 'in zone' and 'not in zone', depending on whether the body point is within a specific zone (or group of zones).
• Acceleration – The rate of change of velocity of the body point over time, indicating how quickly it is speeding up or slowing down.
• Acceleration State – A categorization of the acceleration behavior, typically defined by thresholds: 'accelerating', 'decelerating', or 'constant speed'.
• Distance to Zone – The shortest distance between a body point and the border of a specific zone (or group of zones).
• Distance to Point – The shortest distance between a body point and a particular point of interest. (Centers of arenas and zones are automatically defined as points.)
• Zone Transitions – The number of times an animal moves between a user-defined sequence of zones (2 or more).
• Zone Alternations – The number of times an animal visits a user-defined number of zones consecutively (typically used in Y-maze experiments).
• Target Visits and Errors – Number of errors and successes in e.g. Barnes maze target zone or baited arm in radial maze.
• Heading to Point – Direction of movement of a body point between one sample and the previous, relative to a user-defined point. This indicates to what degree the animal moves towards the point, regardless of whether the animal faces the point.
• Heading – Direction of movement of a body point between one sample and the previous, relative to a line parallel to the x-axis in the coordinate system.
• Turn Angle (Relative and Absolute) – The change in moving direction of a body point between one sample and the previous. Relative turn angle takes the direction of turning into account (clockwise or anti-clockwise), whereas absolute turn angle does not.
• Angular Velocity (Relative and Absolute) – The change in moving direction of a body point per unit of time. Relative angular velocity takes the direction of turning into account.
• Meander – The change in moving direction of a body point, relative to the distance moved. It is a measure of the tortuosity of a trajectory. Relative meander takes the direction of turning into account.
• Movement – A discrete variable with two possible states, 'moving' and 'not moving', indicating whether the spatial movement of a body point is within user-definable speed thresholds.
• Mobility State – A discrete variable with three possible states, 'highly mobile', 'mobile', and 'immobile', indicating the percentage of change in the animal's surface area between consecutive samples, with user-definable thresholds.
• Mobility – Calculates the mobility for which the complete area detected as animal is changing, even if the center point remains at the same place.
• Rotation – The number of clockwise and/or counter-clockwise rotations made by the animal, in which the definition of a rotation can be freely chosen (for instance turning 360°, 180°, or 90°).
• Activity State – The duration of levels of activity within the arena boundaries. It calculates four levels of activity (high, active, moderately active and inactive) based on user definable thresholds.
• Activity – The percentage of activity within the arena boundaries.
• Manually Scored Events – Behaviors that were scored manually.
• Free Interval – For custom analysis of interval duration, cumulative durations, etc.
• Body Elongation State – A discrete variable with three possible states, 'stretched', 'normal', and 'contracted', indicating the elongation percentage of the animal's body, with user definable thresholds.
• Body Elongation – This parameter indicates the elongation percentage of the animal's body per user defined averaging interval.
• Head Directed to Zone – The duration the animal's head is directed towards a specific zone or a circular area around a point.
• Body Angle State – The body angle of the animal over a user-defined interval with output in four states: 'Straight', 'Bent', 'Bent Clockwise' and 'Bent Counterclockwise'.
• Body Angle – The body angle of the animal (relative or absolute) per sample point.

Multiple Body Points

• Head Direction – The smallest angle formed by the direction that the nose point is pointing towards in a certain sample, relative to a line parallel to the x-axis.

Social Interaction

• Distance Between Subjects – The distance between a body point of one animal and a body point of another animal.
• Body Contact – Contact between the bodies of two animals (not related to body points, but to the whole detected area of the animal's body).
• Proximity – A discrete variable with two possible states, 'in proximity' and 'not in proximity', indicating whether an animal is within the proximity of another animal, with user-definable thresholds.
• Relative Movement – Discrete variable describing the animal's movement relative to another animal with four possible states: 'moving to', 'moving from', 'no relative movement', and 'no interaction'. The maximum interaction distance is user-definable.
• Net Weighted Movement – The signed, distance-weighted change in distance between two subjects from one sample to the next.
• Weighted Movement From – The distance-weighted change in distance between subjects, when an animal (actor) is moving away from another animal (receiver).
• Weighted Movement To – The distance-weighted change in distance between subjects, when an animal (actor) moves towards another animal (receiver).
• Social Contact [NEW] – Detected when the nose point of the subject (actor) is near a conspecific (receiver) and the actor's center-nose vector is oriented toward the receiver's body points by less than the specified angle.
• Approach [NEW] – Detected when the subject (actor) moves toward a conspecific (receiver) within the specified distance, the angle between the actor's center-nose vector and the receiver's center point is less than specified, and the receiver moves at a velocity lower than specified.
• Following [NEW] – Detected when the subject (actor) follows a conspecific (receiver) within the specified distance, the actor's nose is oriented towards the receiver's center point within the specified angle, and both animals move faster than specified.
• Leaving [NEW] – Detected when the subject (actor) moves away from a conspecific (receiver) within the specified distance, the angle between the actor's center-nose vector and the receiver's center point exceeds the specified threshold.

Source: EthoVision XT 19 Technical Specifications - Rodent, Noldus Information Technology