The elevated plus maze for the assessment of activity and anxiety in a wild subterranean rodent: role of illumination and mystacial vibrissae

The elevated plus maze (EPM) test is widely used for assessing anxiety-like behavior. A variety of factors and procedural variables can influence behavior in the EPM. In the case of subterranean rodents, which spend most of their lives in constant darkness and are exposed to extensive somatosensory stimuli, both illumination levels and vibrissae removal can exert profound effects on their EPM behavior. Hence, the behavior of a wild subterranean rodent, Ctenomys talarum, was investigated in the EPM under two contrasting illumination levels in combination with removal of mystacial vibrissae. Illumination conditions and vibrissal removal did not affect transparent arm exploration in the EPM. Besides, low illumination intensity caused an increase in the distance traveled by tuco-tucos (C. talarum), although absence of vibrissae caused a clear exploration decrement. Both life-history characteristics and experimental conditions must be taken into account when using the EPM to assess anxiety and other behavioral parameters