Linda Ruggiero
BS (Loyola College, MD), PhD (Oregon Health & Science University).

Research Interests: Circadian rhythms, retinal circuitry, behavioral light responses

In mammals, light input through the retina is responsible for entraining the circadian clock, located in the suprachiasmatic nucleus
(SCN)of the hypothalamus. This system is of great importance to an organism as it controls a number of biological rhythms including, but not limited to, bioluminescence in cyanobacteria, photosynthesis in plants, and hormone production and secretion and the sleep/wake cycle in mammals. Entrainment to light occurs via projections to the SCN from a subset of intrinsically photosensitive retinal ganglion cells which express the photopigment, melanopsin.  Cells of the SCN exhibit heterogeneity in the types of molecules they express. One molecule of interest in our lab is calbindin (CalB), a cytosolic-calcium binding protein present in some SCN neurons. CalB appears to play an important role in circadian function because ablation of the CB-positive subnucleus causes disruption in activity rhythms. In addition, in the absence of CalB, photoentrainment does not occur, however, the ability to phase shift in response to light is intact. I am currently interested in understanding what underlies the differences in photoentrainment and phase shifting. I am working on examining these differences at the behavioral level by manipulating exposure to varying wavelengths and intensities of light. In addition, I am interested in studying potential changes at the level of the retina and the SCN. Because CalB is localized with melanopsin in a subset of cells in the retina, I am interested in looking at potential interactions between these molecules.