Immunohistochemically labelled feedback neurons in the learning and memory center of a crustacean brain. Neuroanatomical evidence suggests that this region shares morphological characteristics across Arthropoda (crustaceans, hexapods, chelicerates, & myriapods) indicating that this important and elaborate brain region may have existed in a common invertebrate ancestor hundreds of millions of years ago.” Confocal microscopy.

By Marcel Sayre from Functional Zoology