Light and dark have significant direct effects on sleep, temperature, and neuroendocrine function independent of their roles as regulators of circadian rhythms. Light therapy is being used with increasing frequency to treat a variety of conditions, including depression, circadian rhythm disorders, and sleep disturbances related to aging. Although the mechanisms for light entrainment of circadian rhythms have been studied extensively, the mechanisms for direct photic effects on sleep and temperature have not been elucidated. A better understanding of the direct effects could make light a more powerful clinical tool. We propose to study the mechanisms for direct light effects on sleep in an animal model. Light promotes sleep in both albino and pigmented rats. However, our research has shown that the effect on rapid eye-movement sleep (REM) is opposite in albino and pigmented rats. Light suppresses REM in albinos but stimulates it in pigmented rats. Albino rat show REM triggering following lights-off, whereas pigmented rats show decreases in REM during dark periods. Differences in central visual pathways have been described in albino vs. pigmented mammals. It is likely that albino and pigmented rats show differences in REM patterns in response to light because of differences in their visual systems. The existence of both behavioral and anatomic differences associated with pigmentation status provides a model for studying the mechanisms mediating the direct effects of light on sleep. The following studies are proposed to determine direct effects of light and dark on sleep induction, REM regulation, and temperature in congenic albino and pigmented rats: 1. Determination of how the direct effects of light vary with light intensity, wavelength, and duration. 2. Determination of the effect of age on the direct responses to light. 3. Investigation of the mediation of the direct effects by comparing visual pathways in albino and pigmented rats, lesioning specific visual pathways, and studying mutant strains of rats with retinal hypopigmentation.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
5R01MH052226-03
Application #
2034115
Study Section
Clinical Neuroscience and Biological Psychopathology Review Committee (CNBP)
Project Start
1995-01-01
Project End
1998-12-31
Budget Start
1997-01-01
Budget End
1997-12-31
Support Year
3
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Wisconsin Madison
Department
Psychiatry
Type
Schools of Medicine
DUNS #
161202122
City
Madison
State
WI
Country
United States
Zip Code
53715
Hanlon, Erin C; Benca, Ruth M; Baldo, Brian A et al. (2010) REM sleep deprivation produces a motivational deficit for food reward that is reversed by intra-accumbens amphetamine in rats. Brain Res Bull 83:245-54
Prichard, J Roxanne; Armacanqui, Hilda S; Benca, Ruth M et al. (2007) Light-dependent retinal innervation of the rat superior colliculus. Anat Rec (Hoboken) 290:341-8
Fleming, M D; Benca, R M; Behan, M (2006) Retinal projections to the subcortical visual system in congenic albino and pigmented rats. Neuroscience 143:895-904
Rattenborg, Niels C; Obermeyer, William H; Vacha, Erika et al. (2005) Acute effects of light and darkness on sleep in the pigeon (Columba livia). Physiol Behav 84:635-40
Prichard, J Roxanne; Fahy, Jennifer L; Obermeyer, William H et al. (2004) Sleep responses to light and dark are shaped by early experience. Behav Neurosci 118:1262-73
Steininger, Teresa L; Kilduff, Thomas S; Behan, Mary et al. (2004) Comparison of hypocretin/orexin and melanin-concentrating hormone neurons and axonal projections in the embryonic and postnatal rat brain. J Chem Neuroanat 27:165-81
Prichard, J R; Stoffel, R T; Quimby, D L et al. (2002) Fos immunoreactivity in rat subcortical visual shell in response to illuminance changes. Neuroscience 114:781-93
Parsons, M J; Benca, R M; Brownfield, M S et al. (2001) Age-associated changes in the serotonergic system in rat superior colliculus and pretectum. Brain Res Bull 55:435-44
Benca, R M; Obermeyer, W H; Larson, C L et al. (1999) EEG alpha power and alpha power asymmetry in sleep and wakefulness. Psychophysiology 36:430-6
Miller, A M; Miller, R B; Obermeyer, W H et al. (1999) The pretectum mediates rapid eye movement sleep regulation by light. Behav Neurosci 113:755-65

Showing the most recent 10 out of 18 publications