© Universität Bielefeld
Fly Electrophysiology
The spatiotemporal retinal motion patterns generated on the eyes during behaviour provide the animal, especially during flight, with information about self-motion, on the one hand, but also with information about the environment, on the other hand. In particular, during translatory flight spatial information about the environment can be gained from the optic flow without sophisticated computations. In the insect brain, visual motion is rapidly processed in an amazingly efficient way. How are the mechanisms in the visual system tailored to achieve the performance observed? Answering this question requires to understand, on the one hand, the constraints imposed by the complexities of the environments in which the animals normally operate. Environments may be complex with regard to their spatial layout and textural properties and may change on a variety of timescales. On the other hand, one needs to know the specific dynamics that is imposed on the retinal image flow by the animals’ behavioural dynamics as a consequence of the closed action-perception cycle.
Flies extract visual motion from the spatio-temporal brightness modulations received by their retinae and represent complex optic flow patterns in the activity pattern of a group of wide-field neurons, further down their visual motion pathway. While these neurons have been discussed to be specific detectors for rotational movements, the elements of this group also respond vigorously during translational movements of the animal. In an alternative functional interpretation, the same group of neurons can thus also be seen as an ensemble representing information about the complex motion pattern in their joint activity. For the readout of behaviourally relevant information from neuronal ensemble activity, modulations in the activity caused by adaptation processes or neuro-modulatory states should ideally affect all elements of the ensemble simultaneously.
Current research: By parallel recording of the neuronal activity of mirror symmetric elements of the ensemble from both brain hemispheres, we investigate how closely the activity levels of these neurons are coupled.