Target visits and errors

Definition

An event marking the time when the animal visits a zone defined as target, or non-target (error) zone.

How to specify Target visits and errors

1.Click the Add button next to Target visits and errors.

2.In the Target Visits and Errors tab, under Settings, choose the Target zones and the Non-target zones.

Under Threshold, enter the Zone exit threshold. That is, once the animal is detected in the zone, the animal is considered to be in the zone until its distance from the zone border exceeds that threshold. Use this option to remove false re-entries resulting from random movements of the body point around the zone border. Click for an example.

3.Under Calculate Statistics for, select the options you require:

▪Target first visits: Visits to zones defined as targets.

▪Target revisits: Revisits to the target zones (to analyze working memory).

▪Non-target first visits: First visits to non-target zones.

▪Non-target revisits: Revisits to non-target zones (to analyze reference memory).

▪Total errors: The total number of non-target zone visits and target zone revisits.

4.In the Body points tab, select the body point(s) you want to use for calculation.

If you have chosen two or three body points, select one of the following from the list:

▪Each point: Visits are scored for each point separately. This results, for example, in one value of Successes for Center-point, and one value of Successes for Nose-point.

▪Any selected point: Visits are scored no matter which selected point enters a zone.

▪All selected points: Visits are scored when all the selected points are in a zone simultaneously.

5.Complete the procedure to add the variable. See Calculate statistics: procedure.

Below: Visualization of Target visits and errors scores in a radial-arm maze. Left: the mouse visits an arm for the second time. This is scored as Target revisit; Total errors is also scored. Right: the mouse visits an arm for the first time. This is scored as a Target first visit.

 

Application

▪In a Barnes maze experiment, use Target visits and errors to analyze spatial reference memory. Calculate the number of successes and errors and their latencies, and compare those figures between probe trials (with escape hole being closed) and training trials. tip: Select Nose-point to estimate nose pokes.

▪In a Radial-arm maze experiment, use Target visits and errors to analyze working memory. Define the baited ends of the maze as targets. Calculate the number of target first visits and target revisits. To calculate the time needed to visit all arms, choose the Trial Statistic Latency to Last and in the results locate this statistics in the Target first visits column.

note  Latency is always calculated from the start of the track, even when you define time bins and nesting intervals.

▪See also the EthoVision XT 19 - Application Manual for more information on the Radial-arm maze test.