Three-dimensional spatial cognition in a benthic fish, Corydoras aeneus

Area of Science:

• Animal behavior
• Spatial cognition
• Neuroethology

Background:

• Animal movement influences spatial learning and memory.
• Pelagic fish encode vertical and horizontal space similarly.
• Benthic fish, while capable of 3D movement, are hypothesized to prioritize horizontal space due to substrate interaction.

Purpose of the Study:

• To investigate how benthic fish (Corydoras aeneus) encode and utilize 3D spatial information.
• To determine if C. aeneus integrate 3D space or process dimensions separately.
• To test whether C. aeneus prioritize vertical or horizontal spatial information when conflicting cues are presented.

Main Methods:

• Utilized a fully rotational Y-maze to test spatial encoding in C. aeneus.
• Assessed the ability to decompose 3D trajectories into vertical and horizontal components.
• Examined prioritization of spatial dimensions during conflicting information scenarios.

Main Results:

• Contrary to hypothesis, C. aeneus demonstrated superior extraction of vertical information compared to horizontal.
• Results indicate robust learning and memory associated with the vertical axis in C. aeneus.
• C. aeneus consistently prioritized vertical information when it conflicted with horizontal information.

Conclusions:

• Benthic fish, C. aeneus, exhibit a preference for vertical spatial information.
• This suggests a strong reliance on and robust encoding of the vertical axis.
• Hydrostatic pressure is proposed as a potential unique cue driving this vertical axis preference.