Physiology

Deep Brain Stimulation

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Science  20 Aug 2010:
Vol. 329, Issue 5994, pp. 885
DOI: 10.1126/science.329.5994.885-d
CREDIT: NAKANE ET AL., PROC. NATL. ACAD. SCI. U.S.A. 107, 10.1073/PNAS.1006393107 (2010)

Seasonal changes are reflected in the phenotype and physiology of many organisms, for example, changes of color or insulating power in fur or feathers, and also in reproductive activity. Tracking the seasons can be achieved by detecting the variation in the length of the day, and the vertebrate eye is the most obvious organ that would be involved, but work from nearly a century ago suggested that deep brain photoreceptors do exist.

In studies of the seasonal breeder the Japanese quail (Coturnix japonica), Nakane et al. report the identification of Opsin 5 as a deep brain photoreceptor that functions in seasonal reproduction. This opsin responds to short-wavelength light, and neurons expressing Opsin 5 (shown stained brown in the paraventricular organ) are structurally similar to retinal photoreceptor cells. The projections of these neurons reach the vicinity of the pituitary, providing a photoperiodic transduction pathway from sunlight to the neuroendocrine system. Because Opsin 5 is also expressed in the mammalian retina and brain, this pathway may be germane to human physiology and behavior.

Proc. Natl. Acad. Sci. U.S.A. 107, 10.1073/pnas.1006393107 (2010).

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