creators_name: Bullock, T.H.
creators_name: Karamürsel, Sacit
creators_name: Hofmann, Michael H.
type: journalp
datestamp: 1999-10-21
lastmod: 2011-03-11 08:53:41
metadata_visibility: show
title: Interval-specific event related potentials to omitted stimuli in the electrosensory pathway in elasmobranchs: an elementary form of expectation
ispublished: pub
subjects: behav-neuro-sci
subjects: bio-behav
subjects: brain-img
subjects: neuro-chem
subjects: neuro-mod
subjects: neuro-neu
subjects: neuro-physio
subjects: neuro-physio
subjects: neuro-psych
full_text_status: public
keywords: Evoked potentials; Event related potentials; Omitted stimulus; Electroreception; Thornback ray; Stingray
abstract: Multiunit activity and slow local field potentials show Omitted Stimulus Potentials (OSP) in the electrosensory system in rays after a missing stimulus in a 3 to >20 Hz train of microvolt 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, midbrain 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.
date: 1993
date_type: published
publication: J Comp Physiol
volume: 172
pagerange: 501-510
refereed: TRUE
citation:   Bullock, T.H. and Karamürsel, Sacit and Hofmann, Michael H.  (1993) Interval-specific event related potentials to omitted stimuli in the electrosensory pathway in elasmobranchs: an elementary form of expectation.  [Journal (Paginated)]     
document_url: http://cogprints.org/121/1/interval_specific_event.htm