The motion after-effect: local and global contributions to contrast sensitivity

Karin Nordström, David C. O'Carroll

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)
3 Downloads (Pure)


Motion adaptation is a widespread phenomenon analogous to peripheral sensory adaptation, presumed to play a role in matching responses to prevailing current stimulus parameters and thus to maximize efficiency of motion coding. While several components of motion adaptation (contrast gain reduction, output range reduction and motion after-effect) have been described, previous work is inconclusive as to whether these are separable phenomena and whether they are locally generated. We used intracellular recordings from single horizontal system neurons in the fly to test the effect of local adaptation on the full contrast-response function for stimuli at an unadapted location. We show that contrast gain and output range reductions are primarily local phenomena and are probably associated with spatially distinct synaptic changes, while the antagonistic after-potential operates globally by transferring to previously unadapted locations. Using noise analysis atid signal processing techniques to remove 'spikelets', we also characterize a previously undescribed alternating current component of adaptation that can explain several phenomena observed in earlier studies.

Original languageEnglish
Pages (from-to)1545-1554
Number of pages10
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1662
Publication statusPublished - May 2009
Externally publishedYes

Bibliographical note

This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


  • Adaptation
  • After-potential
  • Contrast threshold
  • Spike generation
  • Spikelets
  • Waterfall effect


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