In each issue of MedLines, we will feature a question posed by a Med Associates customer that is typcial of questions we often receive. Featured questions may be derived from phone-in or email support calls, or they may be taken from our new Med Associates User Forum.
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For our first issue of the newsletter, we have formulated a series of questions that were not posed by any one person in particular. Rather, they are representative of common questions we hear regarding one of our most popular research tools, Open Field Activity Monitor.
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System in Question: Activity Monitor Software (SOF-811) used for locomotor activity analysis in conjunction with our Open Field Activity Chambers (e.g. ENV-510, ENV-515) |
Question 1: In Activity Monitor, under the Block Summary Analysis, why does the Average Velocity not equal the Distance Traveled divided by the Time Ambulatory? |
Answer:
Activity Monitor calculates a velocity for each Ambulatory Episode. An Ambulatory Episode occurs when the animal breaks enough beams (defined by the Ambulatory Trigger) within a certain amount of time (defined as the Resting Delay). Settings for Ambulatory Trigger and Resting Delay should be selected so that Ambulatory Episodes are counted when the animal is moving around the Activity Chamber.
Activity Monitor Software takes the number of Ambulatory Episodes that occurred in the given Block, and reports the Average Velocity of those Ambulatory Episodes. |
Question 2: If there is only one Ambulatory Episode in the Block, will the Average Velocity be the Distance Traveled divided by the Time Ambulatory? |
Answer:
If one, and only one, Ambulatory Episode started and ended in the given Block, then yes, the Average Velocity will equal the Distance Traveled divided by the Time Ambulatory.
If, however, the Ambulatory Episode started in a previous Block, only part of that Ambulatory Episode's distance and time will be counted in the given Block, so the Average Velocity will not be equal to the Distance Traveled divided by the Ambulatory Time for that Block.
Also, if one Ambulatory Episode started and ended in the given Block, and then a second Ambulatory Episode started later in the Block, and the second episode ended in the next Block, the given Block would only report 1 Ambulatory Episode (as only 1 completed in that Block), but the distance and time figures for the given Block would include part of the second Ambulatory Episode, and the Average Velocity will not be equal to the Distance Traveled divided by the Ambulatory Time for that Block. |
Question 3: What are the Box Size, Resting Delay, and Ambulatory Trigger and how do they relate to the Stereotypic Counts and Ambulatory Counts? |
Answer:
The Box Size is the number of beams on the X- and Y-axes that are used to create a Box around the animal. The Box needs to be large enough to contain the animal. 4 beams x 4 beams are usually large enough, but some animals may require a larger Box Size.
When the animal is moving and breaking beams inside of the Box, which can happen when the animal is grooming, rearing, etc., the beam breaks are counted as Stereotypic events. |
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As soon as the animal moves outside of the Box and breaks enough beams to meet the Ambulatory Trigger in a time that is less than the Resting Delay, the animal becomes Ambulatory. All beam breaks are now counted as Ambulatory. When the animal takes longer than the Resting Delay to break new beams outside of the Box, the animal becomes Stereotypic and the Ambulatory Episode is complete.
For Example:
Ambulatory Trigger: 3
Resting Delay: 500 ms
Box Size: 4x4
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| When the animal moves fast enough to break 3 beams in less than 500ms, it is then considered to be Ambulatory. It stays Ambulatory until the animal slows down and fails to break 3 beams in less than 500ms. The Ambulatory Episode stops and the animal becomes Stereotypic. |
