Part 4/10:
One of the more captivating topics Levin touched upon was the concept of plasticity in biological organisms, particularly in metamorphosis. For example, the transformation of a caterpillar into a butterfly is a radical process whereby the caterpillar's nervous system is dismantled and rebuilt. Despite this dramatic transformation, studies reveal that learned behaviors and memories remain intact.
This theme extends to regeneration, evidenced by Levin's work with flatworms—if a planarian loses a head, it can grow a new one while retaining its established spatial memory of where its home environment is. Such observations raise questions about how memories can be encoded and retrieved even when the biological medium undergoes a significant transformation.