Species-specific differences in sensorimotor adaptation are correlated with differences in social structure

Area of Science:

• Neuroethology
• Comparative neurobiology
• Animal behavior

Background:

• Weakly electric fish use electric organ discharge (EOD) for navigation and communication.
• The jamming avoidance response (JAR) is a behavior to prevent frequency jamming by conspecifics.
• JAR performance leads to long-term frequency elevation (LTFE) of EOD, a form of neural plasticity.

Purpose of the Study:

• To investigate species differences in long-term sensorimotor adaptation of EOD in weakly electric fish.
• To correlate the strength and duration of LTFE with the social structure and jamming probability of different species.

Main Methods:

• Comparative study of two weakly electric fish species: Eigenmannia virescens (shoaling) and Apteronotus leptorhynchus (solitary).
• Electrophysiological recordings of EOD frequencies.
• Analysis of long-term frequency elevation (LTFE) duration and strength following jamming avoidance response (JAR) behavior.

Main Results:

• A significant species difference was observed in the strength and duration of LTFE.
• LTFE was stronger and persisted longer in the shoaling species (Eigenmannia virescens) compared to the solitary species (Apteronotus leptorhynchus).
• In Apteronotus leptorhynchus, LTFE decayed within 5-9 hours, while it remained elevated in Eigenmannia virescens.

Conclusions:

• Long-term sensorimotor adaptation of EOD is modulated by species-specific social behavior and jamming encounter probability.
• The observed differences in LTFE suggest a link between neural plasticity, memory, and ecological niche in electric fish.
• Intrinsic excitability changes in the electromotor pacemaker nucleus underlie this adaptive memory, reflecting social structure.