Journal of Comparative Physiology A

, Volume 172, Issue 4, pp 501–510

Interval-specific event related potentials to omitted stimuli in the electrosensory pathway in elasmobranchs: an elementary form of expectation

  • T. H. Bullock
  • S. Karamürsel
  • M. H. Hofmann

DOI: 10.1007/BF00213532

Cite this article as:
Bullock, T.H., Karamürsel, S. & Hofmann, M.H. J Comp Physiol A (1993) 172: 501. doi:10.1007/BF00213532


Multiunit activity and slow local field potentials show Omitted Stimulus Potentials (OSP) in the electrosensory system in rays (Platyrhinoidis triseriata, Urolophus halleri) after a missing stimulus in a 3 to >20 Hz train of μV pulses in the bath, at levels from the primary medullary nucleus to the telencephalon. A precursor can be seen in the afferent nerve. The OSP follows the due-time of the first omitted stimulus with a, usually, constant main peak latency, 30–50 ms in medullary dorsal nucleus, 60–100 ms in midbrain, 120–190 ms in telencephalon — as though the brain has an expectation specific to the interstimulus interval (ISI). The latency, form and components vary between nerve, medulla, mid-brain and forebrain. They include early fast waves, later slow waves and labile induced rhythms. Responsive loci are quite local. Besides ISI, which exerts a strong influence, many factors affect the OSP slightly, including train parameters and intensity, duration and polarity of the single stimulus pulses. Jitter of ISI does not reduce the OSP substantially, if the last interval equals the mean; the mean and the last interval have the main effect on both amplitude and latency.

Taken together with our recent findings on visually evoked OSPs, we conclude that OSPs do not require higher brain levels or even the complexities of the retina. They appear in primary sensory nuclei and are then modified at midbrain and telencephalic levels. We propose that the initial processes are partly in the receptors and partly in the first central relay including a rapid increase of some depressing influence contributed by each stimulus. This influence comes to an ISI-specific equilibrium with the excitatory influence; withholding a stimulus and hence its depressing influence causes a rebound excitation with a specific latency.

Key words

Evoked potentials Event related potentials Omitted stimulus Electroreception Thornback ray Stingray 



dorsal nucleus of medullary lateral line lobe




evoked potential


event related potential


induced rhythm


interstimulus interval


omitted stimulus potential


mesencephalic lateral nucleus


positive peak at 75 ms

Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • T. H. Bullock
    • 1
  • S. Karamürsel
    • 2
  • M. H. Hofmann
    • 3
  1. 1.Neurobiology Unit, Scripps Institution of Oceanography and Department of NeurosciencesUniversity of CaliforniaSan Diego, La JollaUSA
  2. 2.Department of PhysiologyIstanbul Medical FacultyIstanbulTurkey
  3. 3.Department of AnatomyUniversity of GöttingenGermany

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