GELIFES Seminars - Karin Nordström

Karin Nordström (Flinders University, Australia)

Motion vision in a small brain

Many animals use visual cues when navigating through the surround. For example, an animal’s own motion through the world creates widefield, self-generated optic flow across the retina, which can be used to stay on a straight path, and to avoid obstacles. However, some features in the surround move independently of such self-generated optic flow. For example, a bird flying past will move along an independent trajectory compared with the self-generated optic flow. Similarly, a rapidly approaching object, will also move inconsistently with the remaining surround.

Independent object motion is important for detecting e.g. predators, prey and conspecifics. In hoverflies, target detection is predominantly used in conspecific interactions. This behaviour is believed to be subserved by small target motion detector (STMD) neurons found in the optic lobes and their presumed post synaptic counterparts, target selective descending neurons (TSDNs), which project to the motor command centres. These descending neurons respond with high specificity to the motion of small targets. STMDs, but intriguingly not TSDNs, are capable of robust responses even against velocity matched optic flow. By comparing our neurophysiological data with behaviour, we aim to understand neural encoding in biological relevant context.

Biosketch:
Karin Nordström is a neuroscientist with a special interest in motion vision. She has been working on hoverfly motion vision since 2004, trying to understand the mechanisms underlying sensory selectivity. Besides electrophysiological techniques, Karin’s lab uses quantitative behavior, image statistics, field work and other ecology techniques to understand how the natural environment may shape visual processing. Karin is a Matthew Flinders Professor at Flinders University in Adelaide, Australia.