Somatosensory evoked potentials in the telencephalon of Atlantic salmon (Salmo salar) following galvanic stimulation of the tail.
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.
Nordgreen
Janicke
J
Department of Pharmacology and Toxicology, Norwegian School of Veterinary Science, Oslo, Norway. janicke.nordgreen@veths.no
Horsberg
Tor Einar
TE
Ranheim
Birgit
B
Chen
Andrew C N
AC
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D005712:Galvanic Skin Response / Q000502:physiology*; D012474:Salmon / Q000033:anatomy & histology* / Q000502:physiology; D013623:Tail / Q000294:innervation*; D013687:Telencephalon / Q000502:physiology*