The mind and brain of an octopus: smart supercharged-snail. (APSF 22032)

APSF 22032 | Amount: $44,791 | Project Leader: WS Chung | Project Period:

A project undertaken at The University of Queensland, and supervised by Dr Wen-Sung Chung.

Cephalopods are a group of ancient molluscs which emerged as a lineage shortly after the Cambrian explosion (ca. 500 million years ago, a period of rapid visual system evolution), long before the first vertebrates. Since then, octopuses (> 200 extant species) have spread throughout all ocean habitats (from tropical to polar region; from reef flat to abyss (>6000 m depth)) and developed various types of adaptations such as changes in their body forms (muscular versus gelatinous body), eye shapes (hemispherical versus tubular shape), complexity of nervous systems (smoothed brain versus wrinkled brain), locomotion patterns (drifting versus crawling), and foraging strategy (visual contact versus chemotactile).

Blue-lined octopus

Octopuses also catch our imagination that they are the masters of colour-blind camouflage, solving complex tasks and their cognitive ability is said to approach that of some small mammals (i.e., foraging navigation, interspecific collaborative hunting and observational learning and maternal care). Despite intense interest and some research progress, much of our knowledge of octopus neuroanatomy, behaviour and ecology comes from a few coastal species which are mainly active during night time. While octopuses are living in diverse habitats including complex coral reefs to the relatively featureless mid-water and have different habits. There they encounter different selection pressures, may be related to the daily rhythm (nocturnal versus diurnal) or constant dark realm and mostly solitary or partially social. How these different ecologies and behavioural differences influence the octopus central nervous system (CNS) remains largely unknown.

Argonauta

This project aims to use the phylogenetically- and ecologically-informed comparisons amongst diurnal and nocturnal coastal species along with pelagic and deep-sea species. This study will reveal that gross anatomy and characteristic neuroanatomical changes of the selected species and then draw links related to their habits and habitats. This is the first step towards understanding of how evolution has shaped the sensory systems, brain structures and behaviours in octopuses. Another objectives are set out to investigate octopus main sensory function and the associated brain lobe as well as the underlying neural network by combining a suite of methods including MRI-based analyses, immunostaining histology, in situ behavioural observation and electrophysiological approaches. 

Telescope-eyed octopus

Using these approaches, this project aims to provide new insights as follows: 

(1) To describe the neural architecture (volumetric estimates of brain lobes, delineation of both previously described and undescribed subdivisions of brain areas) and brain-wide MRI-based neural network of the selected octopus species (benthic versus drifting dwellers, coastal versus deep-sea, solitary versus paired-bond, diurnal versus nocturnal) using the methods developed by the research team.

(2) To identify novel visual circuits and retinotopic arrangement and clarify their vision function and chemo-tactile function using diffusion MRI, tractography and electrophysiological methods to investigate the core sensory integration mechanisms in their visual and chemosensory centres using the coastal species.

(3) To build a new model of network neuroscience based on the structural and functional circuits in octopuses.

The expected outcomes will unfold how octopus brain design and associated adaptations affect their behaviour and ecology of these short-life span creatures as well as lead the way for novel analyses of invertebrate neuroarchitecture, sensory function and evolutionary neuroscience. Notably, within the current push towards comparisons of cognitive abilities between octopuses and primates, often with unashamed anthropomorphism at their root, the new findings during this project will provide a firm grounding from which to work.