Behavioural state affects motion-sensitive neurones in the fly visual system

Abstract

SUMMARYThe strength of stimulus-induced responses at the neuronal and the behavioural level often depends on the internal state of an animal. Within pathways processing sensory information and eventually controlling behavioural responses, such gain changes can originate at several sites. Using motion-sensitive lobula plate tangential cells (LPTCs) of blowflies, we address whether and in which way information processing changes for two different states of motor activity. We distinguish between the two states on the basis of haltere movements. Halteres are the evolutionarily transformed hindwings of flies. They oscillate when the animals walk or fly. LPTCs mediate, amongst other behaviours, head optomotor responses. These are either of large or small amplitude depending on the state of motor activity. Here we find that LPTC responses also depend on the motor activity of flies. In particular, LPTC responses are enhanced when halteres oscillate. Nevertheless, the response changes of LPTCs do not account for the corresponding large gain changes of head movements. Moreover, haltere activity itself does not change the activity of LPTCs. Instead, we propose that a central signal associated with motor activity changes the gain of head optomotor responses and the response properties of LPTCs.

Elementary Motion Detection

“…An increase in spontaneous activity is in accordance with work done in parallel on state-dependent influences of other lobula plate tangential cells in Drosophila and Calliphora Haag et al, 2010;Longden and Krapp, 2009;Longden and Krapp, 2010;Maimon et al, 2010;Rosner et al, 2010). In principle, four different behavioral states were investigated: application of CDM (Longden and Krapp, 2009), passive and active movement of the halteres Rosner et al, 2010), walking and flying (Maimon et al, 2010). Three of these studies included work on spiking neurons, which makes a quantitative comparison possible Longden and Krapp, 2009;Rosner et al, 2010).…”

“…The other behavioral states are the flight condition and the CDM application condition. In the following I will compare the findings of this study with previous work (Heide, 1983) and recent literature on the effect of the behavioral state in flies Haag et al, 2010;Longden and Krapp, 2009;Longden and Krapp, 2010;Maimon et al, 2010;Rosner et al, 2010). Heide (1983) in collaboration with his colleagues Foster and McCann also recorded from a lobula plate tangential cell which they assumed to be H1.…”

“…In insect neurobiology, the question of how behavior influences sensory processing has received more and more attention in recent years Haag et al, 2010;Maimon et al, 2010;Rind et al, 2008;Rosner et al, 2010). Using motion-sensitive (Schneider, 1953;Miller, 1977;Sandeman and Markl, 1980 (Rosner et al, 2010).…”

“…Using motion-sensitive (Schneider, 1953;Miller, 1977;Sandeman and Markl, 1980 (Rosner et al, 2010). In contrary, during walking and flying (Maimon et al, 2010) the response gain of LPTCs was greatly increased.…”

“…Experiments pointing in these directions were recently published Rosner et al, 2010). LTPCs or descending neurons were recorded while the halteres were either moving actively or passively.…”