Olfactory Imprinting to Amino Acids is Unpredictable but Specific

Area of Science:

• Behavioral Neuroscience
• Olfactory Learning
• Animal Behavior

Background:

• Olfactory imprinting influences later-life responses to early-life cues.
• Responses to complex olfactory mixtures can be complicated by individual odorant effects.

Purpose of the Study:

• To investigate how dissimilar odorant responses within a mixture affect olfactory imprinting.
• To determine if imprinted animals respond to mixture constituents individually.

Main Methods:

• Zebrafish were developmentally exposed to specific amino acids (L-leucine, L-lysine, L-valine) or a control (β-phenylethyl alcohol).
• Adult zebrafish preference responses to these chemicals and their mixtures were measured.

Main Results:

• Imprinting occurred for β-phenylethyl alcohol, L-leucine, and L-lysine, but not L-valine.
• L-leucine and L-lysine evoked attraction and avoidance, respectively.
• Fish imprinted to an L-leucine and L-lysine mixture responded only to the mixture, not individual amino acids.
• The imprinting response to the mixture was influenced by the aversive amino acid, indicating differential weighting of constituents.

Conclusions:

• An olfactory imprinting cue is perceived as a unique entity, irrespective of its complexity.
• Individual components of an imprinted olfactory mixture can have varying importance, particularly in species using chemical profiles for navigation.