Comparison of Circadian Changes in the Retinas of Migrating and Non-migrating Blackcaps, Sylvia atricapilla
Year: 2006
Type: dissertation
Abstract: The retinas of birds and other vertebrates undergo morphological and physiological \nchanges throughout the day, which help regulate daily changes in visual sensitivity. One \nparticular change is the contraction and elongation of photoreceptor outer segments, \nwhich is regulated by an endogenous circadian clock. Normally, Blackcaps (Sylvia \natricapilla) are diurnal, but they migrate at night. In the current experiment, outer \nsegment lengths of migrating and non-migrating Blackcaps were measured throughout \nthe day and analyzed, and they show a trend toward circadian rhythmicity across the \nday. There also appears to be an advance in the phase of the rhythm in retinomotor \nmovements when birds are migrating. These results indicate that circadian-controlled \nretinomotor movements could be modifications within the retina to accommodate the \nnocturnal lifestyle of migratory Blackcaps. We hypothesize that a change in retinal physiology and morphology may allow the formation of a migratory “night-vision” to \naccommodate the migrating Blackcap’s nocturnal lifestyle.
Author: Ross Shockley
Language: English
Subfield: Endocrine and Autonomic Systems
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2602395063