The Nervous System Of Octopuses

Question 1

Octopus

Answer 1

• belongs to mollusca, the phylum
  -> also includes snails, clams and chitons
• las common ancestor of humans and octopodes: 2mm flatworm 750 million years ago

Question 2

Anatomy

Answer 2

In what could be tought of as the ‘head’:
- siphon (to draw in water or expel it)
- digestive system and mouth
- three hearts
- reproductive organs and anus

Question 3

Physiological Uniquities

Answer 3

• no spine
• no joints
• 1000s of finger-like suckers
  –> can move and touch themselves/others in a great many more ways than we can

Question 4

Multiple brains?

Answer 4

number depends on the defintion of the brain
- only have one organ at the centre of their nervous system
- BUT non-central organs also do brain like functions
–> 2 to 9 brains

Grasso and Hocher –> the example of the organisation of the octopus nervous system in relation to adaptive behaviour
- observable behaviour is a result of the interactions of its parts (in space and with intrinsic ‘memory’ capacity in time) -> is an exponentially larger set of functions than sum of its parts
- behaviour arises from the system as a whole through dynamic physical and information interactions among all its components NOT like an open-loop robotic systems, hierarchical top-down control
truly distributed processes of the brachial plexus serve to give the octopus something just close enough to this degree of control using a distributed computational method

Question 5

What is a brain?

Answer 5

1. an organ which is the centre of the nervous system
   - there exists some causal regularity
   -> change type A in nervous system lead to change type B in brain state
2. has the function of processing information (cognition) and controlling behaviour

Question 6

What is the nervous system?

Answer 6

= the set of all connected cells (which transmit electrical impulses in a particular way) + cells that support their functioning (glial cells…)

Question 7

What is cognition?

Answer 7

1. adaptive type of processing, not just any sort of pattern manipulation
2. a function from stimulus inputs to behavioural outputs –> changes over time on the basis of prior activation
3. function evolves so that the output (resultant behaviour) is better suited to the environment and the goals of the organism

Question 8

Human versus octopus nervous system

Answer 8

Human
- 86 Billion neurons in the brain
- 100 Billion neurons in the peripheral nervous system

Octopus
- 50 Million neurons in the central brain
- 160 Million neurons in separate optic lobes
- 320 Million neurons in branchial ganglia in its arms

Question 9

Arm Nerve Cords: Somatotopic maps

Answer 9

octopus arms are highly complex

Somatotopic maps?
= cortical or subcortical arrangements of sensory inputs and local circuits that reflect the topological organisation of the body
- in humans: several areas of the nervous system are organised somatotopically –> can be found in the spinal cord, cerebellum and somatosensory cortex
- in octopodes: no somatotopic maps found so far in central nervous system
-> possibly due to the lack of joints –> would make somatotopic representation overly complex and redundant
-> OR bc spatial and proprioceptive information can already be represented in the neural networks found in arm cords

Question 10

Octopodes in the lab: learning and cognition

Answer 10

There is a lot of research on octopus learning behaviour –> good learning capacity
- also applies to ‘artificial’ environments in labs (cf opening a jar)
- domain-general cognition –> cognitive abilites and behaviours that are flexible and adaptive within a variety of situations

are curious about world, show great extent of individual behaviour patterns

Question 11

Examples of skills

Answer 11

1. various visual distinction capacities (mirror images , humans wearing identical uniforms) –> implies capability of concept formation
2. long term memory –> stable up to several months, impressive considering their life spans

rather surprising finding:
- usually live a solitary life
- lack of central nervous system
- BUT human-centric thinking

Possible explanation:
- live on floor of the ocean alongside many predators and food –> need to move around and learn to interact adaptively
- opening jars may be similar to natural behaviour of opening bivalve shells
- are predators that need to navigate and discriminate, remember
- can learn a lot of things but are rather slow –> speed of learning depends on reward