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Evidence of conditioned behavior in amoebae
Ildefonso M De la Fuente1,2, Carlos Bringas3, Iker Malaina4
1Department of Nutrition, CEBAS-CSIC Institute, Espinardo University Campus, Murcia, 30100, Spain. mtpmadei@ehu.eus.
Nature Communications
|August 17, 2019
Summary
Unicellular organisms, like Amoeba proteus, demonstrate associative learning by linking stimuli to create conditioned behaviors. This finding challenges the notion that complex nervous systems are required for associative memory.
Area of Science:
- Cellular biology
- Neuroscience
- Behavioral science
Background:
- Associative memory is crucial for complex organisms' adaptation.
- Previously, associative learning was exclusively observed in multicellular species with nervous systems.
- The capacity for associative learning in unicellular organisms remained unexplored.
Purpose of the Study:
- To investigate the presence of associative learning in the unicellular organism Amoeba proteus.
- To determine if unicellular organisms can exhibit conditioned behavior.
Main Methods:
- Amoeba proteus were exposed to a direct-current electric field (conditioned stimulus) and a chemotactic peptide (unconditioned stimulus).
- The organism's motility patterns were observed and analyzed following the paired stimuli.
- The study utilized a related species, Metamoeba leningradensis, for comparative analysis.
Main Results:
- Amoeba proteus exhibited a motility pattern indicative of associative conditioning.
- The unicellular organisms successfully linked independent stimuli, demonstrating conditioned behavior.
- This conditioned behavior persisted for an average of 44 minutes, and similar results were observed in Metamoeba leningradensis.
Conclusions:
- Unicellular organisms, including Amoeba proteus, possess the capacity for associative learning.
- Behavioral modification through associative conditioning is possible in single-celled organisms.
- The findings suggest that associative memory may not be exclusive to organisms with complex nervous systems.
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