Journal of Comparative Physiology A

, Volume 193, Issue 12, pp 1235–1242 | Cite as

Somatosensory evoked potentials in the telencephalon of Atlantic salmon (Salmo salar) following galvanic stimulation of the tail

  • Janicke Nordgreen
  • Tor Einar Horsberg
  • Birgit Ranheim
  • Andrew C. N. Chen
Original Paper


Electric activity in the brain which is time-locked to a given stimulation of the somatosensory system can be recorded as a somatosensory evoked potential (SEP). We investigated whether a galvanic stimulation of the tail base in Atlantic salmon (Salmo salar) would elicit a SEP in the telencephalon. The telencephalon is central in learning and memory, and activity here may be a prerequisite for processing of external stimuli on a cognitive or emotional level. Anaesthetized salmon (n = 11) were subjected to craniotomy and a recording electrode was inserted into the telencephalon. The fish were given stimulations of four intensities, i.e., 2, 5, 10 and 20 mA. A SEP was elicited in the contralateral dorsal telencephalon for all intensities. This result agrees with findings in other fish species. Furthermore, there was a significant difference between the maximum peak amplitude and mean amplitude of the SEP elicited by putative non-noxious (2 mA) and putative noxious (20 mA) stimulation intensities (P < 0.01). The stronger stimulation intensities also tend to introduce longer-latencies components in the SEP. The results added to the body of literature indicates that the exteroceptive senses are represented by processing within the telencephalon of the fish.


Nociception Pain SEP Salmon Teleost 



Somatosensory evoked potential


Inter stimulus interval


Maximum effect


Stimulus strength giving 50% effect


Stimulus strength (mA)


milli ampere


Dorsal zone of the dorsal (pallial) telencephalon


Dorsal plus dorsolateral zone of the dorsal (pallial) telencephalon


Lateral zone of the dorsal (pallial) telencephalon


Medial zone of the dorsal (pallial) telencephalon


Central zone of the dorsal (pallial) telencephalon


Posterior zone of the dorsal (pallial) telencephalon


Posterior lateral line nerve



We are grateful to Claudia Spadavecchia, Andreas Haga, Kristine Walhovd and Trond Svendsen for advice and discussions concerning the experimental set-up and analysis of data. We would also like to thank three anonymous referees for helpful comments. Thanks to the staff at ANT-ASA for good support concerning the use of their equipment on a new species in an aquatic environment. This work was funded by the Norwegian Research Council, grant no. 159667/S40, and the Norwegian School of Veterinary Science.


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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Janicke Nordgreen
    • 1
  • Tor Einar Horsberg
    • 1
  • Birgit Ranheim
    • 1
  • Andrew C. N. Chen
    • 2
  1. 1.Department of Pharmacology and ToxicologyNorwegian School of Veterinary ScienceOsloNorway
  2. 2.Center for Higher Brain FunctionsCapital Medical UniversityBeijingPeople’s Republic of China

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