PhenoTyper: Avoidance learning (shelter task)
LSID: http://syli.cz/urn:lsid:public.sylics.com:automatedtest:649A-B2GB-D783Materials and Methods
Mice were singly housed on sawdust in standard Makrolon type II cages enriched with cardboard nesting material for at least one week prior to experiments, with water and food ad libitum (7:00/19:00 lights on/off; providing an abrupt phase transition).
Activity in the home cage was automatically recorded by video tracking in specially designed cages (PhenoTyper model 3000, Noldus Information Technology, www.noldus.com/phenotyper). Each cage contains a top unit with built-in hardware for video-tracking, that is, an infrared-sensitive video camera. The latter provide constant and even illumination of the cage. An infrared filter placed in front of the camera prevents interference with room illumination. This method allows continuous behavioural recordings in both dark and light periods. EthoVision was used as video tracking and trial control software. PhenoTyper cages were connected in a specially designed computer network. The cages (L =30 × W =30 × H =35 cm) were made of transparent Perspex walls with an opaque Perspex floor covered with bedding based on cellulose. A feeding station and a water bottle were attached on to two adjacent walls outside of the cage. A shelter (height: 10 cm, diameter: 9 cm; non-transparent material) was fixed in one of the corners. The X-Y coordinates of the centre of gravity of mice were acquired and smoothed using EthoVision software and processed to generate behavioural parameters using AHCODA analysis software (Synaptologics BV, Amsterdam, The Netherlands, http://www.sylics.com/bioinformatics/ahcodatm-data-analysis/).
Associated Mammalian Phenotype Ontologies (MGI)
- MP:0001362 abnormal anxiety-related response
- MP:0001462 abnormal avoidance learning behaviour
- MP:0002063 abnormal learning/memory/conditioning
Avoidance learning (shelter task)
The PhenoTyper is equipped with a shelter compartment, with two entrances, in which mice typically spend 80% of their time (resting/sleeping). During the first 4 days, mice develop a preference to enter the shelter through one of the two entrances. The preference index is calculated by : [(number of entries through the preferred entrance) - (number of entries through
non-preferred entrance)]/(total number of entries).
Avoidance learning is studied by automatically applying a mild aversive stimulus (shelter illumination with bright light) during days 5 and 6 each time mice entered the shelter using their preferred entrance, but not when using the other entrance. A reduction in the preference index indicates that a mouse is establishing a specific association between its preferred entrance and the aversive stimulus. During day 7 sanctioning (i.e. shelter illumination) is discontinued, and the stability of the change in preference can be determined.
Avoidance learning is best studied during the Dark phase when shelter illumination is a stronger stimulus than during the light phase. For a detailed explanation see Maroteaux et al. (http://www.ncbi.nlm.nih.gov/pubmed/22846151)
The behavior during this task can be visualized in the multi-day preference index curve (plotting Dark phase 4 -7), see C57BL/6J mice as an example:
http://mousedata.sylics.com/?page=strainhtp&loaded=true&s=11&htpid=243&e=2&batch=1&t=&texp=&list=batches&tdose=
Parameter information
| Parameter name | Units | Explanation |
| Preference index | Preference index | The preference index was determined as follows: [(number of entries through the preferred entrance) - (number of entries through non-preferred entrance)]/(total number of entries). |
| Aversion index | Index | The aversion index was defined as follows: [(time spent in the illuminated shelter after entering through the sanctioned entrance) - (time spent in the dark shelter after entering through the non-sanctioned entrance)]/(total time spent in shelter) |
| *Preference index - Dark phase | Preference index (Dark4, Dark5, Dark5 and Dark7) | |
| *Aversion index - Dark phase | Aversion index (Dark4, Dark5, Dark5 and Dark7) | |
| Short shelter visit preference index - Dark phase | Preference index (Dark4, Dark5, Dark5 and Dark7) | |
| Long shelter visit preference index - Dark phase | Preference index (Dark4, Dark5, Dark5 and Dark7) | |
| Short shelter visit aversion index - dark | Aversion index (Dark4, Dark5, Dark5 and Dark7) | |
| Long shelter visit aversion index - dark | Aversion index (Dark4, Dark5, Dark5 and Dark7) |