On the 6th December, Bangor’s own Sarah Zylinski gave a talk to the Biological society about Cephalopod vision.

Cephalopods are a group marine invertebrates, characterised by a large, well developed brain. They tend to reside in divers habitats.

The group includes octopus, squid and cuttlefish.

Cephalopods eyes are convergent to fishes, and have extraordinary capabilities that attract a lot of attention for researchers.

Cephalopod Eyes

Although cephalopod eyes are convergent to fishes eyes they have evolved independently of one another.

Both eyes contain a camera-type chamber eye, this is where the retina is at the back of the eye as opposed to at the front of the eye.

This removes the complications of the blind spot that normally occurs within an eye.

Within the eye the optic lobe is often bigger than the brain, also there are photopigments on the microvilli.

Dynamic colouration

Some cephalopods are capable of dynamic colouration which is a rapid response under direct neural control. The response is visual.

In cephalopods there is inter and intra specific signalling and control.

Visual perception

Dynamic colouration makes cephalopods very interesting subjects for visual perception.

Visual perception also allows us to see what they see through visual perception.

Scene->Eye->Optic lobe->Brain->Chromataphore Lobe->Body Pattern->Output

When testing the capabilities that cephalopods have the rang is flexible but limited and not as effective compared to when they are in their natural habitat.

The visual system is sensitive to luminescence boundaries and produces the same response if it was faced with a whole object.

Fragmented Visuals

Sarah’s research shows that cephalopods provide a correct response to the edge of an object.

Here research has also shown that they can put together information from partial sides. Foe example they can make a full circle from several different pieces of circle.

This ability, known as contour completion, is useful for avoiding predators.

You can read Sarah’s full paper here.

My Thoughts

This whole talk was immensely interesting to me. I already had an interest in the survival mechanics of cephalopods due to their uniqueness and this talk further piqued that interest.  Not only did it show off one of the unique features that these animals have but it also showed me many research pathways that I could take within this field.