60. Rieger D, Wülbeck C, Rouyer F, Helfrich-Förster C.
Period Gene Expression in Four Neurons Is Sufficient for Rhythmic Activity of Drosophila melanogaster under Dim Light Conditions. J Biol Rhythms. 2009 Aug;24(4):271-82.

59. Helfrich-Förster C. Does the morning and evening oscillator model fit better for flies or mice? J Biol Rhythms. 2009 Aug;24(4):259-70.

58. Johard HA, Yoishii T, Dircksen H, Cusumano P, Rouyer F, Helfrich-Förster C, Nässel DR. Peptidergic clock neurons in Drosophila: ion transport peptide and short neuropeptide F in subsets of dorsal and ventral lateral neurons. J Comp Neurol. 2009 Sep 1;516(1):59-73.

57. Yoshii T, Ahmad M, Helfrich-Förster C. Cryptochrome mediates light-dependent magnetosensitivity of Drosophila's circadian clock. PLoS Biol. 2009 Apr 7;7(4):e1000086.

56. Yoshii T, Wülbeck C, Sehadova H, Veleri S, Bichler D, Stanewsky R, Helfrich-Förster C. The neuropeptide pigment-dispersing factor adjusts period and phase of Drosophila's clock. J Neurosci. 2009 Feb 25;29(8):2597-610.

55. Kempinger L, Dittmann R, Rieger D, Helfrich-Forster C. The nocturnal activity of fruit flies exposed to artificial moonlight is partly caused by direct light effects on the activity level that bypass the endogenous clock. Chronobiol Int. 2009 Feb;26(2):151-66.

54. Wülbeck C, Grieshaber E, Helfrich-Förster C  Pigment-dispersing factor (PDF) has different effects on Drosophila's circadian clocks in the accessory medulla and in the dorsal brain. J Biol Rhythms. 2008 Oct;23(5):409-24.

53. Helfrich-Förster C., Yoshii T., Wülbeck C., Grieshaber E., Rieger D., Bachleitner B., Cusamano P., Rouyer F. (2008) The Lateral and Dorsal Neurons of Drosophila melanogaster: New insights about their morphology and function. Cold Spring Harbor Labor., in press.

52. Yoshii T., Todo T., Wülbeck C., Ralf Stanewsky R., Helfrich-Förster C. (2008) Cryptochrome operates in the compound eyes and a subset of Drosophila’s clock neurons. J. Comp. Neurol., in press.

51. Hamasaka Y., Rieger D., Parmentier M.-L., Grau Y., Helfrich-Förster C., Nässel D.R. (2007) Glutamate and its Metabotropic Receptor in Drosophila Clock Neuron circuits. J. Comp. Neurol. 505, 32-45.

50. Rieger D., Fraunholz C., Popp J., Bichler D., Dittmann R., Helfrich-Förster C. (2007) The fruit fly Drosophila melanogaster favours dim light and times its activity peaks to early dawn and late dusk. J. Biol. Rhythms 22, 387-399.

49. Bachleitner W., Kempinger L., Wülbeck C., Rieger D. and Helfrich-Förster C. (2007) Moonlight shifts the endogenous clock of Drosophila melanogaster. PNAS 104 (9), 3538-3543.

48. Veleri S., Rieger D., Helfrich-Förster C. and Stanewsky R. (2007) Hofbauer-Buchner Eyelet Affects Circadian Photosensitivity and Coordinates TIM and PER Expression in Drosophila Clock Neurons. J. Biol. Rhythms 22, 29-42.

47. Helfrich-Förster C., Shafer O.T., Wülbeck C., Grieshaber E, Rieger D and Taghert P. (2007) Development and morphology of the clock-gene-expressing Lateral Neurons of Drosophila melanogaster. J. Comp. Neurol. 500, 47-70.

46. Wülbeck C. and Helfrich-Förster C. (2006) RNA In Situ hybridizations on Drosophila whole mounts. In: Methods in Molecular Biology, Volume 362, 495-511.

45. Helfrich-Förster C. (2006) Immunohistochemistry in Drosophila, sections and whole mount. In: Methods in Molecular Biology, Volume 362, 533-547.

44. Shafer O.T., Helfrich-Förster C., Renn S.C.P. and Taghert P. (2006) Re-evaluation of Drosophila melanogaster’s neuronal circadian pacemakers reveals new neuronal classes and inter-class neurochemical interactions. J. Comp. Neurol. 498, 180–193.

43. Helfrich-Förster C. (2006) The neural basis of Drosophila’s circadian clock. Sleep Biol. Rhythms 4(3), 224-234.

42. Rieger D., Shafer O.T., Tomioka K. and Helfrich-Förster C (2006) Functional analysis of circadian pacemaker neurons in Drosophila melanogaster, J. Neurosci. 26(9), 2531–2543.

41. Helfrich-Förster C. (2005) PDF Has Found Its Receptor. Neuron 48, 161-163.

40. Helfrich-Förster C. (2005) Organization of endogenous clocks in insects. Biochem Soc Trans.33 (Pt 5): 957-961.

39. Helfrich-Förster C. (2005) Techniques that revealed the network of Drosophila’s clock. In Methods in Enzymology 393, 439-451.

38. Helfrich-Förster C. (2004) Neurobiology of the fruit fly’s circadian clock. Genes Brain Behavior 4, 65-76.

37. Veleri S, Wülbeck C. (2004) Unique self-sustaining circadian oscillators within the brain of Drosophila melanogaster. Chronobiol Int 21(3), 329-342.

36. Wülbeck C., Szabo G., Shafer O.T., Helfrich-Förster C. and Stanewsky R. (2004) The novel Drosophila timblind mutant affects behavioral rhythms but not periodic eclosion. Genetics 169, 751-766.

35. Helfrich-Förster C. (2004) The circadian clock in the brain: a structural and functional comparison between mammals and insects. J. Comp. Physiol. A, 190, 601-613.

34. Helfrich-Förster C. (2003) The neuroarchitecture of the circadian clock in the Drosophila brain. Microscop. Res. Techn. 62, 94–102.

33. Veleri S., Brandes C., Helfrich-Förster C., Hall J.C. and Stanewsky R. (2003) A self-sustaining, light-entrainable circadian oscillator in the Drosophila brain. Curr. Biol. 13: 1758–1767.

32. Rieger D., Stanewsky R. and Helfrich-Förster C. (2003) Cryptochrome, compound eyes, Hofbauer-Buchner eyelets, and ocelli play different roles in the entrainment and masking pathway of the locomotor activity rhythm in the fruit fly Drosophila melanogaster. J. Biol. Rhythms 18: 377-391.

31. Park J.H., Schroeder A.J., Helfrich-Förster C., Jackson F.R. and Ewer J. (2003) Targeted ablation of CCAP neuropeptide-containing neurons of Drosophila causes specific defects in execution and circadian timing of ecdysis behaviour. Development 130: 2645-2656.

30. Helfrich-Förster C. (2002) The circadian system of Drosophila melanogaster and its light input pathways. Zoology 105, 297-312.

29. Helfrich-Förster C., Edwards T., Yasuyama K., Schneuwly S., Stanewsky R., Meinertzhagen, I., and Hofbauer A. (2002) The extraretinal eyelet of Drosophila: development, ultrastructure and putative circadian function. J. Neuroscience 22: 9255-9266.

28. Helfrich-Förster C., Wulf J., and de Belle J.S. (2002) Mushroom body influence on locomotor activity and circadian rhythms in Drosophila melanogaster. J. Neurogenet. 16: 73-109.

27. Helfrich-Förster C. and Engelmann W. (2002). Photoreceptors for the circadian clock of the fruit fly. In: Circadian Rhythms (V. Kumar, ed.), Narosa Publishing House, 94-106.

26. Foster R. and Helfrich-Förster C. (2001) Photoreceptors for circadian clocks in mice and fruit flies. Phil. Trans. R. Soc. Lond. B 356, 1779-1789.

25. Helfrich-Förster C., Winter C., Hofbauer A., Hall J.C., and Stanewsky R. (2001) The circadian clock of fruit flies is blind after elimination of all known photoreceptors. Neuron 30: 249-261.

24. Helfrich-Förster C. (2001) The activity rhythm of Drosophila melanogaster is controlled by a dual oscillator system. J. Insect Physiol. 47: 877-887.

23. Emery P., Stanewsky R., Helfrich-Förster C., Emery-Le M., Hall J.C., and Rosbash M. (2000) Drosophila CRY confers circadian light sensitivity to behavioral pacemaker neurons. Neuron 26: 493-504.

22. Helfrich-Förster C., Täuber M., Park J., Mühlig-Versen M., Schneuwly S., and Hofbauer A. (2000) Ectopic expression of the neuropeptide pigment-dispersing factor alters the rhythm of locomotor activity in Drosophila melanogaster. J. Neuroscience 20: 3339-3353.

21. Park J.H., Helfrich-Förster C., Lee G.-H., Liu L., Rosbash M., Hall J.C. (2000) Differential regulation of circadian pacemaker output by separate clock genes in Drosophila. Proc. Natl. Acad. Sci. USA 97: 3608-3613.

20. Helfrich-Förster C. (2000) Differential control of morning and evening components in the activity rhythm of Drosophila melanogaster - sex specific differences suggest a different quality of activity. J. Biol. Rhythms 15: 135-154.

19. Hao H., Glossop N.R.J., Lyons L., Qui J., Morrish B., Cheng Y., Helfrich-Förster C. and Hardin P. (1999) The 69 bp circadian regulatory sequence (CRS) mediates per-like developmental, spatial, and circadian expression and behavioral rescue in Drosophila. J. Neuroscience 19: 987-994.

18. Helfrich-Förster C., Stengl M. and Homberg U. (1998) Organization of the circadian system in insects. Chronobiol. Internat. 15(6): 567-594.

17. Antkowiak B. and Helfrich-Förster C. (1998) Effects of small concentrations of volatile anesthetics on action potential firing of neocortical neurons in vitro. Anesthesiology 88: 1592-1605.

16. Helfrich-Förster C. (1998) Robust circadian rhythmicity of Drosophila melanogaster requires the presence of Lateral Neurons: A brain-behavioral study of disconnected mutants. J. Comp. Physiol. A 182: 435-453.

15. Kaneko M., Helfrich-Förster C. and Hall J. C. (1997) Spatial and temporal expression of the period and the timeless genes in the developing nervous system of Drosophila: Newly identified pacemaker candidates and novel features of clock-gene product cyclings. J. Neurosci. 17: 6745-6760.

14. Helfrich-Förster C. (1997) Development of pigment-dispersing hormone immunoreactive neurons in the nervous system of Drosophila melanogaster. J. Comp. Neurol. 380:335-354.

13. Helfrich-Förster C. (1996) Drosophila rhythms: from brain to behavior. Sem. Cell Develop. Biol. 7, 791-802.

12. Helfrich-Förster C. (1995) The period clock gene is expressed in central nervous system neurons which also produce a neuropeptide that reveals the projections of circadian pacemaker cells within the brain of Drosophila melanogaster. Proc. Natl. Acad. Sci. USA 92, 612-616.

11. Helfrich-Förster C. and Diez-Noguera A. (1993) Use of a multioscillatory system to simulate experimental results obtained for the period-mutants of Drosophila melanogaster. J. interdiscipl. Cycle Res. 24, 225-231.

10. Helfrich-Förster C. and Homberg U. (1993) Pigment-dispersing hormone-immunoreactive neurons in the nervous system of wild-type Drosophila melanogaster and of several mutants with altered circadian rhythmicity. J. Comp. Neurol. 337, 177-190.

9. Helfrich-Förster C. (1992). Are neurosecretory cells involved in the circadian control of locomotor activity of Drosophila melanogaster? In: Proceedings of the VIIth Annual Meeting of the ESC, Peter Lang Verlag, Frankfurt am Main. pp. 134-140.

8. Helfrich-Förster C. (1991). The behavior of mutant and wildtype flies of Drosophila melanogaster under continuous light conditions. In: Proceedings of the VIth Annual Meeting of the ESC, Peter Lang Verlag, Frankfurt am Main. pp. 97-103.

7. Förster C. and Engelmann W. (1988) Thalassomyxa australis rhythmicity III. Entrainment by combination of different zeitgeber. J. interdiscipl. Cycle Res. 19, 275-288.

6. Smietanko A., Stader L., Förster C. and Engelmann W. (1988) Thalassomyxa australis rhythmicity II. No entrainment by light-dark-cycles and temperature cycles? J. interdiscipl. Cycle Res. 19, 235-240.

5. Helfrich C. and Engelmann W. (1987) Evidences for circadian rhythmicty in the per0 mutant of Drosophila melanogaster. Z. Naturforsch. 42c, 1335-1338.

4. Helfrich C. (1987) Use of Drosophila melanogaster brain mutants for the localization of the pacemaker of circadian locomotor activity rhythm. J. Neurogenetics 4, 137-140.

3. Helfrich C. (1986) Role of the optic lobes in the regulation of the locomotor activity of Drosophila melanogaster: Behavioral analysis of neural mutants. J. Neurogenetics 3, 321-343.

2. Helfrich C., Cymborowski B. and Engelmann W. (1985) Circadian activity rhythm of the house fly continues after optic tract severance and lobectomy. Chronobiol. Internat. 2, 19-31.

1. Helfrich C. and Engelmann W. (1983) Circadian rhythm of the locomotor activity in Drosophila melanogaster and its mutants "sine oculis" and "small optic lobes". Physiol. Entomol. 8, 257-272.