Modification of Light
Rearing in complete darkness from birth leaves the cortex in a flexible state that can be altered by sensory perturbation even in adulthood (Cynader, 1983; Mower, 1991; Fagiolini et al., 1994; Daw, 1995). A litter is placed in total darkness during different periods of development or after reaching adulthood and then exposed to light for certain periods of time.
Modification of Sound
A litter (with their mother if younger than P21) inside a standard cage with food and water ad libitum is placed in a chamber isolated from external sound on a 12:12 light/dark cycle. Mice will stay in the acoustic chamber for a particular period of time. Acoustic stimuli are played 24 hours/day during the exposure time period. Mice are monitored continuously by an infrared camera surveillance system for any abnormal activities or movements in response to the sound stimuli. Recorded acoustic stimuli range from con-specific ultrasounds, modified ultrasound calls, pure tones of audible range (7 to 15kHz), white noise or silence (control).
Impoverished and enriched environments are known to lead to different effects on subsequent behavior. In particular, cognitive performance and levels of stress are known to vary considerably between animals reared in such differing environments and levels of thermal and mechanical sensitivity following nerve injury and inflammation are also known to be affected. One of the main concerns though is that many laboratories use different enrichment protocols and thus it is not possible to make direct comparisons between laboratories. In an era where the lack of ability to reproduce the work of others in the life sciences has been estimated to cost the US $28 billion [PLoS Biol. 2015 Jun 9;13(6):e1002165. doi: 10.1371/journal.pbio.1002165. The Economics of Reproducibility in Preclinical Research. Freedman LP, Cockburn IM, Simcoe TS.] the use of standardized enrichment protocols may be seen as an important experimental detail.
We have available such standardized enrichment cages that mice may be reared in from birth or introduced at any stage of development. http://www.viewpoint.fr/en/p/equipment/marlau-enrichment-cage