The effect of monocular deprivation on unihemispheric sleep in light and dark incubated/reared domestic chicks

Abstract

Unihemispheric sleep is an aspect of the cerebral lateralization of certain species of birds. During sleep, domestic chicks (Gallus gallus) show brief periods of monocular-unihemispheric sleep (Mo-Un sleep): one eye is open and the connected hemisphere is awaken while the other eye remains shut and the connected hemisphere sleeps. The time spent in Mo-Un sleep was investigated following a brief monocular deprivation (MD) in chicks hatched from eggs incubated in darkness and reared in light (D-L), incubated in light and reared in light (L-L) and incubated in darkness and reared in darkness (D-D). The right eye occluded for 12 h in half of chicks and the left eye in the other half. At the end of MD, the Mo-Un sleep was recorded. The effect of MD (total time and time bias) prevailed in determining the pattern of Mo-Un sleep. Chicks showed more time sleeping with the eye/hemisphere that was in control of visual behaviour during MD and opened more time the eye and awake the hemisphere visually deprived. The Mo-Un pattern was not influenced by incubation, rearing, symmetry/asymmetry of visual pathways and imprinting thereby indicating that Mo-Un sleep pattern depends only on the kind of visual experience during wakefulness.

Local Aspects of Avian Non-REM and REM Sleep

“…In future studies, it would be interesting to determine whether NREM sleep time or intensity increase unilaterally following sleep deprivation of only one hemisphere while fur seals sleep unihemispherically in the water. Finally, although unihemispheric sleep deprivation has not been performed in birds, several behavioral studies in chicken chicks have shown small, but significant, changes in the time spent with only the left or right eye closed in response to treatments thought to selectively activate one hemisphere or the other (e.g., Mascetti et al, 2007; Nelini et al, 2010, 2012; Quercia et al, 2018; reviewed in Mascetti, 2016), suggesting that sleep may be homeostatically regulated independently in each hemisphere. It will be important for future studies to determine the extent to which these changes in eye state correlate with changes in hemispheric sleep measured electrophysiologically (see Lesku et al, 2011b).…”

Light‐dependent development of the tectorotundal projection in pigeons

“…There are, however, lateralized functions that develop in chicks independent from light exposure like novelty detection (Rogers, 2008; Rogers et al., 2007), visual choice to approach a social partner (Andrew, Johnston, Robins, & Rogers, 2004; Deng & Rogers, 2002b), avoiding an obstacle (Chiandetti et al., 2013) or monocular sleep in chicks (Bobbo, Galvani, Mascetti, & Vallortigara, 2002; Mascetti & Vallortigara, 2001; Quercia, Bobbo, & Mascetti, 2018). The same has been shown in pigeons for visuospatial attention (Letzner, Güntürkün, Lor, Pawlik, & Manns, 2017) and interocular information transfer (Letzner, Patzke, Verhaal, & Manns, 2014).…”