Reference

Glossary of octopus cognition

Vertical lobe
The octopus's principal learning-and-memory brain structure, functionally analogous to the vertebrate hippocampus; site of long-term potentiation.
Chromatophore
A pigment-filled skin cell, each directly controlled by the nervous system and expanded by tiny muscles, enabling near-instant color change.
Iridophore / Leucophore
Reflective (iridophore) and white-scattering (leucophore) skin cells that combine with chromatophores to produce structural color and camouflage.
Semelparity
A life history in which an animal reproduces a single time and then dies — the norm for most octopuses.
Optic gland
An endocrine gland that, after reproduction, drives the octopus's terminal decline (the 'death spiral'); the cephalopod analog of aspects of vertebrate neuroendocrine aging.
A-to-I RNA editing
A process that chemically changes adenosine to inosine in RNA, recoding proteins after transcription; unusually widespread in cephalopod neural tissue.
Long-term potentiation (LTP)
A durable strengthening of synaptic connections underlying learning and memory; present in the octopus vertical lobe via a distinct nitric-oxide mechanism.
Axial nerve cord
The segmented main nerve running down each octopus arm, coordinating local sensing and movement partly independent of the brain.
Nociception
The neural detection of harmful stimuli. In octopuses it is accompanied by evidence of affective pain, not just reflex.
Convergent evolution
The independent evolution of similar traits in unrelated lineages — e.g. complex cognition arising separately in cephalopods and vertebrates.
Umwelt
The self-centered perceptual world of an organism — the specific slice of reality its senses build, central to understanding octopus experience.
Octopolis / Octlantis
Two documented high-density octopus aggregation sites off Australia where solitary octopuses display unexpected social behavior.