air pollution

Mice exposed for a long term to fine particulate matter have reduced spine density in the CA1 region of the hippocampus as compared with mice exposed to filtered air. These changes in hippocampal morphology are associated with impairments in learning and memory and increased depressive-like responses. Here, we show a (a) bright field image of the hippocampus ( × 25) and (b) a representative pyramidal neuron from the CA1 region ( × 400). Mice exposed to particulate matter showed (c) reduced spine density on CA1 apical dendrites ( × 1000). For more information on this topic, please refer to (Fonken et al, 2011, Mol Psych).


  1. Fonken, L.K., Frank, M.G., Gaudet, A.D., D’Angelo, H.M., Daut, R.D. Hampson, E.C., Ayala, M.T., Watkins, L.R., & Maier, S.F. (2017). Neuroinflammatory priming to stress is differentially regulated in male and female rats (Under review).
  2. Frank, M.G., Fonken, L.K., Annis, J., Watkins, L.R., & Maier, S.F. (2017). Stress disinhibits microglia via down-regulation of CD200: a mechanism of neuroinflammatory priming (Under review).
  3. Gaudet, A.D., Ayala, M.T., Fonken, L.K., Smith, E.J., Bateman, E.M., Schleicher, W.E., Maier, S.F., & Watkins, L.R. (2017). Spinal cord injury in rats disrupts bowel function (Under review).
  4. Gaudet, A.D., Fonken, L.K., Watkins, L.R., Nelson, R.J., & Popovich, P.G. (2017). microRNAs: Roles in regulating neuroinflammation. The Neuroscientist: 107385417721150.
  5. Fonken, L.K., Kitt, M.M., Gaudet, A.D., Barrientos, R.M., Watkins, L.R., & Maier, S.M. (2016). Diminished circadian rhythms in microglia may contribute to age-associated neuroinflammatory priming. Neurobiology of Aging: 47: 102-112.
  6. Fonken, L.K., Frank, M.G., Kitt, M.M., D’Angelo, H.M., Norden, D.M., Weber, M.D., Barrientos, R.M., Godbout J.P., Watkins, L.R., & Maier, S.F. (2016). The alarmin HMGB1 mediates age-induced neuroinflammatory priming. The Journal of Neuroscience 36 (30): 7946-7956.
  7. Gaudet, A.D.*, Fonken, L.K.*, Gushchina, L.V., Aubrecht, T.G., Maurya, S.K., Periasamy, M., Nelson, R.J., & Popovich, P.G. (2016). MicroRNA-155 deletion prevents diet-induced obesity in female mice. Scientific Reports 6: 22862. *equal contributors
  8. Fonken, L.K., Weber, M.D., Daut, R.A., Kitt, M.M., Frank, M.G., Watkins, L.R., & Maier, S.F. (2016). Stress induced neuroinflammatory priming is time of day specific. Psychoneuroendocrinology 66: 82-90.
  9. Fonken, L.K.*, Gaudet, A.D.*, Gaier, K.R.*, Nelson, R.J., & Popovich, P.G. (2016). MicroRNA-155 deletion reduces anxiety- and depressive-like behaviors in mice. Psychoneuroendocrinology 63: 362-369. *equal contributors
  10. Frank, M.G., Weber, M.D., Fonken, L.K., Hershman, S.A., Watkins, L.R., & Maier, S.F. (2016). The redox state of the alarmin HMGB1 is a pivotal factor in neuroinflammatory and microglial priming: a role for the NLRP3 inflammasome. Brain, Behavior, and Immunity 55: 215-224.
  11. Bedrosian, T.A., Fonken, L.K., & Nelson, R.J. (2016). Endocrine effects of circadian disruption. Annual Review of Physiology 78 (1).
  12. Fonken, L.K. & Nelson, R.J. (2016). Effects of light exposure at night during development. Current Opinion in Behavioral Sciences 7: 33-39.
  13. Fonken, L.K., Frank, M.G., Kitt, M.M., Barrientos, R.M., Watkins, L.R., & Maier, S.F. (2015). Microglia inflammatory responses are controlled by an intrinsic circadian clock. Brain, Behavior, and Immunity 45: 171-179.
  14. Fonken, L.K. & Nelson, R.J. (2014). The effects of light at night on circadian clocks and metabolism. Endocrine Reviews 35 (4): 648-670.
  15. Fonken, L.K., Meléndez-Fernández, O.H., Weil, Z.M., & Nelson, R.J. (2014). Exercise attenuates the effects of dim light at night on metabolism. Physiology and Behavior 124: 33-36.
  16. Lui C.*, Fonken, L.K.*, Wang, A., Maiseyeu, A., Bai, Y., Wang, T., Maurya, S., Ko, Y., Periasamy, M., Dvonch, T., Morishita, M., Brook, R.D., Harkema, J., Ying, Z., Mukherjee, B., Sun, Q., Nelson, R.J., & Rajagopalan, S. (2014) Central IKK inhibition prevents air pollution mediated peripheral inflammation and exaggeration of type II diabetes. Particle and Fibre Toxicology 11(1): 53. *equal contributors
  17. Fonken, L.K., Aubrecht, T.G., Melendez-Fernandez, O.H., Weil, Z.M., & Nelson, R.J. (2013). Dim light at night disrupts molecular circadian rhythms and increases body weight. Journal of Biological Rhythms 28(4): 262-71
  18. Fonken, L.K. & Nelson, R.J. (2013). Dim light at night increases depressive-like responses in male C3H/HeNHsd mice. Behavioural Brain Research. 243: 74-78.
  19. Fonken, L.K., Weil, Z.M., & Nelson, R.J. (2013). Dark nights reverse metabolic disruption caused by dim light at night. Obesity 21 (6): 1159-64.
  20. Bedrosian, T.A., Herring, K.L., Walton, J.C., Fonken, L.K., Weil, Z.M., & Nelson, R.J. (2013). Evidence for feedback control of pineal melatonin secretion. Neuroscience Letters 542: 123-5.
  21. Fonken, L.K., Lieberman, R.A., Weil, Z.M., & Nelson, R.J. (2013). Dim light at night exaggerates weight gain and inflammation associated with a high fat diet in male mice. Endocrinology 154 (10): 3817-25.
  22. Fonken, L.K. & Nelson, R.J. (2013). Mice exposed to dim light at night exaggerate inflammatory responses to lipopolysaccharide. Brain, Behavior, and Immunity 34: 159-63.
  23. Fonken, L.K., Haim, A., & Nelson, R.J. (2012). Dim light at night increases immune function in grass rats, a diurnal rodent. Chronobiology International. 29 (1): 26-34.
  24. Bedrosian, T.A., Fonken, L.K., Demas, G.E., & Nelson, R.J. (2012). Photoperiod-dependent effects of neuronal nitric oxide synthase inhibition on aggression in Phodopus sungorus. Hormones and Behavior. 61 (2): 176-80.
  25. Fonken, L.K., Bedrosian, T.A., Michaels, H., Weil, Z.M., & Nelson, R.J. (2012). Short photoperiods attenuate central responses to an inflammogen. Brain, Behavior, and Immunity. 26 (4): 617-22.
  26. Fonken, L.K., Kitsmiller, E., Smale, L., & Nelson, R.J. (2012). Dim nighttime light impairs cognition and provokes depressive-like responses in a diurnal rodent. Journal of Biological Rhythms. 27 (4): 319-27.
  27. Fonken, L.K., Xu, X., Weil, Z.M., Chen, G., Sun, Q., Rajagopalan, S., & Nelson, R.J. (2011). Air pollution impairs cognition, provokes depressive-like behaviors, and alters hippocampal cytokine expression and morphology. Molecular Psychiatry. 16 (10): 987-995.
  28. Fonken, L.K., Xu, X., Weil, Z.M., Chen, G., Sun, Q., Rajagopalan, S., & Nelson, R.J. (2011). Inhalation of fine particulates alters hippocampal neuronal morphology. Molecular Psychiatry. 16 (10): 973.
  29. Fonken, L.K., Morris, J.S., & Nelson, R.J. (2011). Early life experiences affect adult delayed-type hypersensitivity in short- and long-photoperiods. Chronobiology International, 28 (2): 101-108.
  30. Bedrosian, T.A., Fonken, L.K., Walton, J.C., & Nelson, R.J. (2011). Chronic exposure to dim light at night suppresses immune responses in Siberian hamsters. Biology Letters, 7 (3): 468-471.
  31. Bedrosian, T.A., Fonken, L.K., Walton, J.C., Haim, A., & Nelson, R.J. (2011). Dim light at night provokes depression-like behaviors and reduces CA1 dendritic spine density in female hamsters. Psychoneuroendocrinology, 36 (7): 1062-
  32. Fenn, A.M.*, Fonken, L.K.*, & Nelson, R.J. (2011). Sustained melatonin treatment blocks body mass, pelage, reproductive and fever responses to short day lengths in female Siberian hamsters. Journal of Pineal Research, 51 (2): 180-186. *equal contributors
  33. Workman, J.L., Fonken, L.K., Gusfa, J., Kassouf, K., & Nelson, R.J. (2011). Post-weaning environmental enrichment reduces negative affective responses and interacts with behavioral testing to alter nNOS expression. Pharmacology, Biochemistry and Behavior, 100 (1): 25-32.
  34. Fonken, L.K. & Nelson, R.J. (2011). Illuminating the deleterious effects of light at night. F1000 Med Report, 3: 18.
  35. Fonken, L.K., Workman, J.L., Walton, J.C., Weil, Z.M., Morris, J.S., Haim, A., & Nelson, R.J. (2010). Light at night increases body mass by shifting the time of food intake. Proceedings of the National Academy of Sciences, 107 (43): 18664-18669. * featured in F1000 and popular press
  36. Workman, J.L., DeWitt, S.J., Fonken, L.K., & Nelson, R.J. (2010). Environmental enrichment enhances delayed-type hypersensitivity in both short- and long-day Siberian hamsters. Physiology and Behavior, 99 (5): 638-643.
  37. Thomas, N.R., Fonken, L.K., LeBlanc, M., & Cornwell, C.A. (2010). Maternal separation alters social odor preference development in infant mice (Mus musculus). Journal of Comparative Psychology, 124 (3): 295-301.
  38. Fonken, L.K., Finy, M.S., Walton, J.C., Weil, Z.M., Workman, J.L., Ross, J., & Nelson, R.J. (2009). Influence of light at night on murine anxiety- and depressive-like responses. Behavioural Brain Research. 205 (2): 349-354.