The Ellipsoid Body of Drosophila: locomotor activity, cognitive flexibility, sleep and more.
The Ellipsoid Body (EB) of the fly is a neuronal structure within the Central Complex (CX), located around the midline of the Drosophila brain. This structure has been extensively associated with locomotion and a wide range of locomotor parameters. More recently, it has also been related to spatial orientation and navigation, given its processing of visual information. Additionally, clock neurons output their circadian activity onto neurons of the EB in order to modulate sleep/wake cycles. All this, together with the synaptic diversity found in the EB, makes this neuronal center an excellent place to study the computational processes underlying these behaviors and the molecular mechanisms that sustain neuronal computation.
The EB is composed of a conundrum of neurons of different nature; GABAergic, serotoninergic, glutamatergic, dopaminergic and cholinergic neurons are all interconnected within the EB and, together, control a variety of behaviors aforementioned. These various neurons are connected through a rich diversity of synaptic configurations (Martin-Peña et al 2014). Interestingly, we observed a peculiar configuration, coincident synapses, where two independent synapses converge onto a third postsynaptic neuron in a particular geometric configuration, with both presynaptic elements perfectly aligned in front of each other (Martin-Peña et al 2014). The fact that axonal projections of neurons from both sides of the brain overlap within the EB enables the potential for binaural computation in this synaptic structure. We are interested in investigating the neuronal circuit within the EB that supports the formation of several forms of memory, dynamic cognitive flexibility and the cycles of sleep/wake.
